Pub Date : 2026-03-25Epub Date: 2026-02-03DOI: 10.1016/j.apcata.2026.120824
Hongping Fang , Wenjun Liang , Liangang Ma , Chenzi Teng , Dandan Tang , Yuling Nie
The poisoning effects of alkali metals (Na, K) and alkaline earth metals (Ca, Mg) on the catalytic performance of 25 % Fe-Al2O3 simulated red mud catalysts were systematically investigated. The impregnation method was used to prepare the catalysts and evaluate them in toluene oxidation reactions. The introduction of these metals resulted in a modest decline in catalytic activity, with the degree of poisoning generally following the order K > Na > Ca > Mg. Catalyst deactivation was attributed to the combined influence of physical and chemical effects. Physical deactivation was associated with metal-induced structural modifications, leading to reductions in surface area and pore volume. In contrast, chemical deactivation arose from changes in surface acidity, inhibition of the Fe2⁺/Fe3⁺ redox cycle, and a decrease in oxygen vacancy concentration. In particular, the presence of Na and Ca caused pronounced suppression of red mud activity. Consequently, for the effective utilisation of red mud as a catalyst, it is essential to minimise the contents of Na and Ca while appropriately adjusting surface acidity to optimise the catalytic performance of the active Fe2O3 component.
系统研究了碱金属（Na、K）和碱土金属（Ca、Mg）对25% % Fe-Al2O3模拟赤泥催化剂催化性能的中毒效应。采用浸渍法制备了催化剂，并对其在甲苯氧化反应中的性能进行了评价。这些金属的引入导致催化活性适度下降，中毒程度一般为K >； Na >； Ca >； Mg。催化剂失活是物理和化学作用共同作用的结果。物理失活与金属诱导的结构改变有关，导致表面积和孔隙体积减少。相比之下，化学失活源于表面酸度的变化、Fe2 + /Fe3 +氧化还原循环的抑制以及氧空位浓度的降低。特别是，Na和Ca的存在引起了赤泥活性的明显抑制。因此，为了有效利用赤泥作为催化剂，必须尽量减少Na和Ca的含量，同时适当调节表面酸度，以优化活性Fe2O3组分的催化性能。
{"title":"Influence mechanism of alkali and alkaline earth metals on red mud catalysts for the catalytic oxidation of toluene","authors":"Hongping Fang , Wenjun Liang , Liangang Ma , Chenzi Teng , Dandan Tang , Yuling Nie","doi":"10.1016/j.apcata.2026.120824","DOIUrl":"10.1016/j.apcata.2026.120824","url":null,"abstract":"<div><div>The poisoning effects of alkali metals (Na, K) and alkaline earth metals (Ca, Mg) on the catalytic performance of 25 % Fe-Al<sub>2</sub>O<sub>3</sub> simulated red mud catalysts were systematically investigated. The impregnation method was used to prepare the catalysts and evaluate them in toluene oxidation reactions. The introduction of these metals resulted in a modest decline in catalytic activity, with the degree of poisoning generally following the order K > Na > Ca > Mg. Catalyst deactivation was attributed to the combined influence of physical and chemical effects. Physical deactivation was associated with metal-induced structural modifications, leading to reductions in surface area and pore volume. In contrast, chemical deactivation arose from changes in surface acidity, inhibition of the Fe<sup>2</sup>⁺/Fe<sup>3</sup>⁺ redox cycle, and a decrease in oxygen vacancy concentration. In particular, the presence of Na and Ca caused pronounced suppression of red mud activity. Consequently, for the effective utilisation of red mud as a catalyst, it is essential to minimise the contents of Na and Ca while appropriately adjusting surface acidity to optimise the catalytic performance of the active Fe<sub>2</sub>O<sub>3</sub> component.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"714 ","pages":"Article 120824"},"PeriodicalIF":4.8,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-01-27DOI: 10.1016/j.apcata.2025.120675
Carl Fritsch , Andreas Serwe , Sven Jovanovic , Hariprasad Ranganathan , Marcus Hans , Andreas Hutzler , Jürgen Dornseiffer , Nikolay Kornienko
Zirconia (ZrO2)-, Ceria (CeO2)-, and Calcium (CaO) -promoted Copper oxide (CuO) Zinc oxide (ZnO) catalysts supported on -alumina spheres are synthesized via incipient wetness impregnation (IWI) and characterized using transmission electron microscopy (TEM), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and CO2/H2-TPD. Catalytic performance is evaluated for carbon oxide hydrogenation to methanol (MeOH) in mixed carbon oxide synthesis gas, examining both CO and CO2-conversion pathways and MeOH space–time yields (STY). Temperature- and pressure-dependent reaction equilibria for MeOH formation from CO and CO2, as well as the reverse water-gas shift reaction (RWGS) are investigated to demonstrate promoter effects on surface reaction mechanisms and conversion efficiency towards MeOH and H2O. Reaction kinetics are optimized using a previously formulated re-parametrized two-site Langmuir–Hinshelwood–Hougen–Watson (LHHW) model for each catalyst system, providing comparative kinetic parameters for the binary, ternary, quaternary, and quinary catalyst formulations. The kinetic models demonstrate good numerical agreement with experimental data for both the promoted catalysts. Although CO-rich streams produce the highest MeOH production rates in all samples, the promotion through ZrO2 and CeO2 significantly improved both CO and CO2 conversion (XC) compared to the binary CuO/ZnO catalyst formulation.
{"title":"CO2- and CO-Conversion to Methanol over promoted CuO/ZnO-based infiltration composite catalyst spheres — Characterization, experimentals and comparative reaction kinetics","authors":"Carl Fritsch , Andreas Serwe , Sven Jovanovic , Hariprasad Ranganathan , Marcus Hans , Andreas Hutzler , Jürgen Dornseiffer , Nikolay Kornienko","doi":"10.1016/j.apcata.2025.120675","DOIUrl":"10.1016/j.apcata.2025.120675","url":null,"abstract":"<div><div>Zirconia (ZrO<sub>2</sub>)-, Ceria (CeO<sub>2</sub>)-, and Calcium (CaO) -promoted Copper oxide (CuO) Zinc oxide (ZnO) catalysts supported on <span><math><mi>γ</mi></math></span>-alumina spheres are synthesized via incipient wetness impregnation (IWI) and characterized using transmission electron microscopy (TEM), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and CO<sub>2</sub>/H<sub>2</sub>-TPD. Catalytic performance is evaluated for carbon oxide hydrogenation to methanol (MeOH) in mixed carbon oxide synthesis gas, examining both CO and CO<sub>2</sub>-conversion pathways and MeOH space–time yields (STY). Temperature- and pressure-dependent reaction equilibria for MeOH formation from CO and CO<sub>2</sub>, as well as the reverse water-gas shift reaction (RWGS) are investigated to demonstrate promoter effects on surface reaction mechanisms and conversion efficiency towards MeOH and H<sub>2</sub>O. Reaction kinetics are optimized using a previously formulated re-parametrized two-site Langmuir–Hinshelwood–Hougen–Watson (LHHW) model for each catalyst system, providing comparative kinetic parameters for the binary, ternary, quaternary, and quinary catalyst formulations. The kinetic models demonstrate good numerical agreement with experimental data for both the promoted catalysts. Although CO-rich streams produce the highest MeOH production rates in all samples, the promotion through ZrO<sub>2</sub> and CeO<sub>2</sub> significantly improved both CO and CO<sub>2</sub> conversion (X<sub>C</sub>) compared to the binary CuO/ZnO catalyst formulation.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"713 ","pages":"Article 120675"},"PeriodicalIF":4.8,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrocatalytic water splitting is limited by the sluggish oxygen evolution reaction (OER). This study investigates how structural and electronic modifications in UiO-type zirconium metal–organic frameworks (MOFs) influence their catalytic activity toward the oxygen evolution reaction. UiO-67, constructed from biphenyl-4,4′-dicarboxylate linkers, provides enlarged pore channels that enhance electrolyte accessibility and mass transport, whereas UiO-66-NO2, based on nitro-functionalized terephthalate linkers, incorporates strong electron-withdrawing groups that modulate the local Zr–O–C coordination environment. FE-SEM, FTIR, and N2 sorption analyses confirmed the characteristic fcu topology and high surface areas expected for successful linker incorporation. In 0.1 M KOH, UiO-67 exhibited an overpotential (η10) of 290 mV at 10 mA cm−2, and a Tafel slope of 70 mV dec−1. UiO-66-NO2 required 340 mV to reach 10 mA cm−2, while commercial RuO2 showed an overpotential (η10) of 470 mV under identical conditions. Both MOFs sustained stable activity over 27 h of continuous electrolysis. These results demonstrate that integrating enlarged pore architectures with electron-withdrawing linker functionality can effectively reduce OER overpotentials and enhance charge-transfer characteristics in alkaline media.
电催化裂解水受到析氧反应缓慢的限制。本文研究了uio型锆金属有机骨架（mof）的结构和电子修饰如何影响其析氧反应的催化活性。由联苯-4,4 ' -二羧酸酯连接物构建的UiO-67提供了扩大的孔隙通道，增强了电解质的可及性和质量传递，而基于硝基化对苯二甲酸酯连接物的UiO-66-NO2则包含了强吸电子基团，可调节局部Zr-O-C配位环境。FE-SEM， FTIR和N2吸附分析证实了fcu的特征拓扑结构和高表面积预期成功连接。在0.1 M KOH条件下，uuo -67在10 mA cm−2时的过电位（η10）为290 mV， Tafel斜率为70 mV dec−1。uuo -66- no2需要340 mV才能达到10 mA cm−2，而在相同条件下，商用RuO2的过电位（η10）为470 mV。两种mof的连续电解活性均在27 h以上。这些结果表明，将扩大的孔隙结构与吸电子连接剂功能相结合，可以有效地降低碱性介质中的OER过电位，增强电荷转移特性。
{"title":"Dual design strategy in Zr–MOFs: Enlarged channels and electron-withdrawing linkers boost oxygen evolution","authors":"Ayyavu Thirunarayanan , Sivalingam Gopi , Arasappan Hemamalini , Monica Soler , Francisco Gracia","doi":"10.1016/j.apcata.2026.120799","DOIUrl":"10.1016/j.apcata.2026.120799","url":null,"abstract":"<div><div>Electrocatalytic water splitting is limited by the sluggish oxygen evolution reaction (OER). This study investigates how structural and electronic modifications in UiO-type zirconium metal–organic frameworks (MOFs) influence their catalytic activity toward the oxygen evolution reaction. UiO-67, constructed from biphenyl-4,4′-dicarboxylate linkers, provides enlarged pore channels that enhance electrolyte accessibility and mass transport, whereas UiO-66-NO<sub>2</sub>, based on nitro-functionalized terephthalate linkers, incorporates strong electron-withdrawing groups that modulate the local Zr–O–C coordination environment. FE-SEM, FTIR, and N<sub>2</sub> sorption analyses confirmed the characteristic <em>fcu</em> topology and high surface areas expected for successful linker incorporation. In 0.1 M KOH, UiO-67 exhibited an overpotential (η<sub>10</sub>) of 290 mV at 10 mA cm<sup>−2</sup>, and a Tafel slope of 70 mV dec<sup>−1</sup>. UiO-66-NO<sub>2</sub> required 340 mV to reach 10 mA cm<sup>−2</sup>, while commercial RuO<sub>2</sub> showed an overpotential (η<sub>10</sub>) of 470 mV under identical conditions. Both MOFs sustained stable activity over 27 h of continuous electrolysis. These results demonstrate that integrating enlarged pore architectures with electron-withdrawing linker functionality can effectively reduce OER overpotentials and enhance charge-transfer characteristics in alkaline media.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"713 ","pages":"Article 120799"},"PeriodicalIF":4.8,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147421442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-02-02DOI: 10.1016/j.apcata.2026.120820
Xin Guo , Weitao Wang , Huan Wang , Jiaqi Zhu , Yang Liu , Zhen-Hong He , Yang Yang , Kuan Wang , Zhao-Tie Liu
Given the widespread application of acetophenone, the development of a green synthetic process for selective oxidation from ethylbenzene to acetophenone has garnered significant attention in recent years. This study synthesized a vanadium-cerium bimetallic catalyst (CeVOx), which achieved an 87.2 % conversion rate and 90.2 % selectivity under reaction conditions of 80 °C for 8 h. Solvent effect studies revealed that solvent influence on catalytic performance primarily stems from substrate adsorption and product desorption. Apparent activation energies for the reaction under different solvents were also investigated. Kinetic studies revealed a two-step sequential first-order reaction mechanism, where both high ethylbenzene conversion and high acetophenone selectivity are kinetically controlled. Comprehensive characterization confirmed a synergistic effect between vanadium and cerium, effectively lowering the activation energy barrier. Radical trapping experiments demonstrated the involvement of peroxy radicals and hydroxyl radicals in the reaction process. In addition, the present catalytic system exhibits excellent expansion for ethylbenzene derivatives.
{"title":"Synergistic vanadium-cerium bimetallic oxide catalyst and solvent effect for efficient oxidation of ethylbenzene to acetophenone","authors":"Xin Guo , Weitao Wang , Huan Wang , Jiaqi Zhu , Yang Liu , Zhen-Hong He , Yang Yang , Kuan Wang , Zhao-Tie Liu","doi":"10.1016/j.apcata.2026.120820","DOIUrl":"10.1016/j.apcata.2026.120820","url":null,"abstract":"<div><div>Given the widespread application of acetophenone, the development of a green synthetic process for selective oxidation from ethylbenzene to acetophenone has garnered significant attention in recent years. This study synthesized a vanadium-cerium bimetallic catalyst (CeVO<sub><em>x</em></sub>), which achieved an 87.2 % conversion rate and 90.2 % selectivity under reaction conditions of 80 °C for 8 h. Solvent effect studies revealed that solvent influence on catalytic performance primarily stems from substrate adsorption and product desorption. Apparent activation energies for the reaction under different solvents were also investigated. Kinetic studies revealed a two-step sequential first-order reaction mechanism, where both high ethylbenzene conversion and high acetophenone selectivity are kinetically controlled. Comprehensive characterization confirmed a synergistic effect between vanadium and cerium, effectively lowering the activation energy barrier. Radical trapping experiments demonstrated the involvement of peroxy radicals and hydroxyl radicals in the reaction process. In addition, the present catalytic system exhibits excellent expansion for ethylbenzene derivatives.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"713 ","pages":"Article 120820"},"PeriodicalIF":4.8,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147421444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-01-29DOI: 10.1016/j.apcata.2026.120817
Xiaohang Sun , Shuairen Qian , Hongwei Li , Binhang Yan
The catalytic hydrogenation of CO2 to methanol represents a promising approach for carbon recycling and renewable fuel synthesis. Although Cu/ZnO-based catalysts are well-established for this process, the structure-activity relationship in ZnGa2O4 spinel-promoted catalysts remains poorly understood. In particular, the electronic and defect-related roles of ZnGa2O4 and its interaction with ZnO require further clarification. This work aims to address this gap by designing a series of Cu/ZnO-ZnGa2O4 catalysts with varying Zn/Ga ratios to harness the synergistic effects at their interfaces. The results demonstrated that the ZnO and ZnGa2O4 composite support significantly improves Cu dispersion by creating a higher-surface-area, porous support and ZnO-ZnGa2O4 interface, thereby suppressing Cu agglomeration. And the ZnO dispersion has also been improved by spatially segregating ZnO through spinel formation. Meanwhile, optimizing the Zn/Ga molar ratio to 1:1 markedly enhances both CO2 activation capacity, methanol yield and reaction stability. Quasi in-situ XPS, EPR, CO2-N2O titration, CO2-TPSR and CO2-TPD studies revealed the formation of oxygen vacancies and partially reduced Zn species, which are closely associated with enhanced CO2 adsorption and activation. In-situ DRIFTS provided dynamic evidence of the formation and hydrogenation behavior of key intermediates, highlighting the synergistic role of Cu, ZnO and ZnGa2O4 in facilitating CO2 adsorption and hydrogenation. Based on these insights into the spinel-enhanced activation process, this work provides a foundation for designing structurally optimized Cu-based catalysts for efficient CO2-to-methanol conversion.
{"title":"Understanding the synergistic role of ZnO-ZnGa2O4 in Cu-based catalysts for CO2 hydrogenation to methanol","authors":"Xiaohang Sun , Shuairen Qian , Hongwei Li , Binhang Yan","doi":"10.1016/j.apcata.2026.120817","DOIUrl":"10.1016/j.apcata.2026.120817","url":null,"abstract":"<div><div>The catalytic hydrogenation of CO<sub>2</sub> to methanol represents a promising approach for carbon recycling and renewable fuel synthesis. Although Cu/ZnO-based catalysts are well-established for this process, the structure-activity relationship in ZnGa<sub>2</sub>O<sub>4</sub> spinel-promoted catalysts remains poorly understood. In particular, the electronic and defect-related roles of ZnGa<sub>2</sub>O<sub>4</sub> and its interaction with ZnO require further clarification. This work aims to address this gap by designing a series of Cu/ZnO-ZnGa<sub>2</sub>O<sub>4</sub> catalysts with varying Zn/Ga ratios to harness the synergistic effects at their interfaces. The results demonstrated that the ZnO and ZnGa<sub>2</sub>O<sub>4</sub> composite support significantly improves Cu dispersion by creating a higher-surface-area, porous support and ZnO-ZnGa<sub>2</sub>O<sub>4</sub> interface, thereby suppressing Cu agglomeration. And the ZnO dispersion has also been improved by spatially segregating ZnO through spinel formation. Meanwhile, optimizing the Zn/Ga molar ratio to 1:1 markedly enhances both CO<sub>2</sub> activation capacity, methanol yield and reaction stability. Quasi in-situ XPS, EPR, CO<sub>2</sub>-N<sub>2</sub>O titration, CO<sub>2</sub>-TPSR and CO<sub>2</sub>-TPD studies revealed the formation of oxygen vacancies and partially reduced Zn species, which are closely associated with enhanced CO<sub>2</sub> adsorption and activation. In-situ DRIFTS provided dynamic evidence of the formation and hydrogenation behavior of key intermediates, highlighting the synergistic role of Cu, ZnO and ZnGa<sub>2</sub>O<sub>4</sub> in facilitating CO<sub>2</sub> adsorption and hydrogenation. Based on these insights into the spinel-enhanced activation process, this work provides a foundation for designing structurally optimized Cu-based catalysts for efficient CO<sub>2</sub>-to-methanol conversion.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"713 ","pages":"Article 120817"},"PeriodicalIF":4.8,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147421443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-01-26DOI: 10.1016/j.apcata.2026.120802
Lucia Mengel , Pieter van den Berg , Clara Aletsee , Pieter Neethling , Gurthwin Bosman , Benjamin Agyei-Tuffour , Joshua Tuah Asante , Emmanuel Nyankson , David Dodoo-Arhin , Zwonaka Mapholi , Martin Tschurl , Neill Goosen , Ueli Heiz
TiO2 is one of the most studied photocatalysts for hydrogen evolution. As decoration with a metal co-catalyst is essential for catalytic formation of hydrogen, there is an ongoing search for low-cost alternatives to the currently predominant noble metals. In this work, we directly compare Cu and Pt co-catalysts on anatase TiO2 in liquid ethanol photoreforming in the absence of water and oxygen. Under these conditions, high product selectivities are achievable on the carbonaceous side of the reaction. The activity of Cu is in the same order of magnitude as Pt, which makes Cu a prospective candidate. Our results also indicate that low metal loadings might be favorable to achieve high co-catalyst efficiencies. Additional insights into the photocatalyst behavior under reaction conditions complement the photocatalytic investigation. Namely, color changes and absorbance features in the visible indicate a reduction of both TiO2 and the Cu co-catalyst when excluding water and oxygen from the reaction solution. The surface hydroxyls formed during the photooxidation of the alcohol likely take part in these processes, which can be comprehensively explained when considering previous insights from UHV experiments. Consequently, this work not only suggests Cu to be a suitable and cost-efficient replacement for Pt as a co-catalyst for hydrogen evolution but also indicates that surface hydroxyls might play a decisive role in complex photocatalytic reactions on TiO2 in a liquid environment.
{"title":"Cu/TiO2 as a low-cost alternative to Pt/TiO2 for hydrogen production via photocatalytic ethanol reforming: a direct comparison and mechanistic analysis","authors":"Lucia Mengel , Pieter van den Berg , Clara Aletsee , Pieter Neethling , Gurthwin Bosman , Benjamin Agyei-Tuffour , Joshua Tuah Asante , Emmanuel Nyankson , David Dodoo-Arhin , Zwonaka Mapholi , Martin Tschurl , Neill Goosen , Ueli Heiz","doi":"10.1016/j.apcata.2026.120802","DOIUrl":"10.1016/j.apcata.2026.120802","url":null,"abstract":"<div><div>TiO<sub>2</sub> is one of the most studied photocatalysts for hydrogen evolution. As decoration with a metal co-catalyst is essential for catalytic formation of hydrogen, there is an ongoing search for low-cost alternatives to the currently predominant noble metals. In this work, we directly compare Cu and Pt co-catalysts on anatase TiO<sub>2</sub> in liquid ethanol photoreforming in the absence of water and oxygen. Under these conditions, high product selectivities are achievable on the carbonaceous side of the reaction. The activity of Cu is in the same order of magnitude as Pt, which makes Cu a prospective candidate. Our results also indicate that low metal loadings might be favorable to achieve high co-catalyst efficiencies. Additional insights into the photocatalyst behavior under reaction conditions complement the photocatalytic investigation. Namely, color changes and absorbance features in the visible indicate a reduction of both TiO<sub>2</sub> and the Cu co-catalyst when excluding water and oxygen from the reaction solution. The surface hydroxyls formed during the photooxidation of the alcohol likely take part in these processes, which can be comprehensively explained when considering previous insights from UHV experiments. Consequently, this work not only suggests Cu to be a suitable and cost-efficient replacement for Pt as a co-catalyst for hydrogen evolution but also indicates that surface hydroxyls might play a decisive role in complex photocatalytic reactions on TiO<sub>2</sub> in a liquid environment.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"713 ","pages":"Article 120802"},"PeriodicalIF":4.8,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-01-07DOI: 10.1016/j.apcata.2026.120773
Jiangnan Zhang, Zhou Wang, Jiaxin Hu, Jinyan Tan, Na Zhang, Jun Wang
To clarify the role of bridging groups in the catalytic process, a series of chromium-based precursor catalysts without bridging groups and with two monodentate phosphine ligands were designed. The absence of bridging groups enhanced the structural flexibility, enabling the catalyst to better adapt to the polymerization thermodynamics. Three commercially available substituted diphenylphosphine ligands were used to prepare P-Cr-P type chromium complexes without bridging groups. Among them, the triphenylphosphine system exhibited the best performance, achieving a catalytic activity of 1.06 × 106 g/mol Cr·h at 60 °C and 4 MPa ethylene pressure. The catalyst showed a total selectivity of 82.7 wt% for 1-hexene (17.6 wt%) and 1-octene (65.1 wt%). Density functional theory (DFT) calculations indicated that complex Cr3 thermodynamically favored the tetramerization of ethylene over trimerization, which was consistent with the oligomerization results in the experiment. Continuous space embedding rate analysis of the transition state model showed that the coordination and insertion of ethylene into the nine-membered ring imposed spatial pressure on the ligands, expanding their degrees of freedom. The removal of the bridging group made this process easier to occur.
{"title":"Non-bridged bisphosphine chromium catalysts for ethylene tetramerization: The influence of bridging groups in dynamic catalytic processes","authors":"Jiangnan Zhang, Zhou Wang, Jiaxin Hu, Jinyan Tan, Na Zhang, Jun Wang","doi":"10.1016/j.apcata.2026.120773","DOIUrl":"10.1016/j.apcata.2026.120773","url":null,"abstract":"<div><div>To clarify the role of bridging groups in the catalytic process, a series of chromium-based precursor catalysts without bridging groups and with two monodentate phosphine ligands were designed. The absence of bridging groups enhanced the structural flexibility, enabling the catalyst to better adapt to the polymerization thermodynamics. Three commercially available substituted diphenylphosphine ligands were used to prepare P-Cr-P type chromium complexes without bridging groups. Among them, the triphenylphosphine system exhibited the best performance, achieving a catalytic activity of 1.06 × 10<sup>6</sup> g/mol Cr·h at 60 °C and 4 MPa ethylene pressure. The catalyst showed a total selectivity of 82.7 wt% for 1-hexene (17.6 wt%) and 1-octene (65.1 wt%). Density functional theory (DFT) calculations indicated that complex Cr3 thermodynamically favored the tetramerization of ethylene over trimerization, which was consistent with the oligomerization results in the experiment. Continuous space embedding rate analysis of the transition state model showed that the coordination and insertion of ethylene into the nine-membered ring imposed spatial pressure on the ligands, expanding their degrees of freedom. The removal of the bridging group made this process easier to occur.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"713 ","pages":"Article 120773"},"PeriodicalIF":4.8,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The direct condensation of acetic acid and formaldehyde is an important alternative route to the petroleum-based propylene two-step oxidation process for acrylic acid production. However, the poor activity and stability of traditional vanadium phosphorus oxide catalyst restrict its industrial application. This work precisely regulated the redox reactivity of VPO catalyst via Mo doping, achieving a highly efficient and stable aldol condensation process with a record-high acrylic acid yield (∼30 %) and outstanding productivity (∼50 μmol⋅gcat−1⋅min−1) in 40 h continuous reaction. The introduction of Mo additive induces the phase transformation of (VO)2P2O7 to VOPO4, successfully constituting a dual-phase redox and acid synergistic catalytic center. Meanwhile, the Mo doping increases the concentration of surface adsorbed oxygen species and the catalyst redox reactivity, efficiently participating in reactant activation and promoting acrylic acid production. Ultimately, the rapid surface oxygen redox process stabilizes the dual-phase synergistic sites and effectively eliminates coke deposit precursors, realizing a stable aldol condensation reaction.
{"title":"Precisely regulated redox behavior of Mo-doped VPO catalyst for efficient and stable condensation of acetic acid and formaldehyde to acrylic acid","authors":"Xueting Yu , Caixia Xu , Yijia Wang, Haoyu Wei, Guowei Wang, Chunyi Li, Chaohe Yang, Xiaolin Zhu","doi":"10.1016/j.apcata.2026.120819","DOIUrl":"10.1016/j.apcata.2026.120819","url":null,"abstract":"<div><div>The direct condensation of acetic acid and formaldehyde is an important alternative route to the petroleum-based propylene two-step oxidation process for acrylic acid production. However, the poor activity and stability of traditional vanadium phosphorus oxide catalyst restrict its industrial application. This work precisely regulated the redox reactivity of VPO catalyst via Mo doping, achieving a highly efficient and stable aldol condensation process with a record-high acrylic acid yield (∼30 %) and outstanding productivity (∼50 μmol⋅gcat<sup>−1</sup>⋅min<sup>−1</sup>) in 40 h continuous reaction. The introduction of Mo additive induces the phase transformation of (VO)<sub>2</sub>P<sub>2</sub>O<sub>7</sub> to VOPO<sub>4</sub>, successfully constituting a dual-phase redox and acid synergistic catalytic center. Meanwhile, the Mo doping increases the concentration of surface adsorbed oxygen species and the catalyst redox reactivity, efficiently participating in reactant activation and promoting acrylic acid production. Ultimately, the rapid surface oxygen redox process stabilizes the dual-phase synergistic sites and effectively eliminates coke deposit precursors, realizing a stable aldol condensation reaction.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"713 ","pages":"Article 120819"},"PeriodicalIF":4.8,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-01-22DOI: 10.1016/j.apcata.2026.120800
Zhengxiang Ma , Yanhua Zhang , Qian Zhao , Liya Gao , Dongsheng Zhang , Xinqiang Zhao , Yanji Wang
Adipamide (ADM) is an important intermediate for various polyamides and nitrogen-containing fine chemicals. However, the selective dehydroxylation of α-hydroxyamides remains a significant challenge in catalytic deoxygenation, due to the high bond dissociation energy of aliphatic C–OH bonds and the pronounced electron-withdrawing and intramolecular hydrogen-bonding effects of the amide groups. These structural features greatly stabilize the molecular framework, making C–OH activation difficult under conventional hydrodeoxygenation (HDO) conditions and often leading to undesired C–N or C–C cleavage. In this work, a series of N-modified β-Mo2C catalysts were designed to promote the hydrodehydroxylation (HDH) of 2-hydroxyadipamide (2-HADM) to bio-based ADM. Structural characterizations reveal that nitrogen incorporation forms interstitial Mo–N–Mo environments within the Mo2C lattice, thereby tuning the electronic structure and acid–base properties of Mo sites. The optimized β-Mo2C-N-650 catalyst achieves a 33.2 % conversion and 92.0 % selectivity to ADM at 150 °C and 4 MPa H2. Density functional theory (DFT) calculations further suggest that nitrogen doping may lower the transition-state barrier for C–OH bond scission and stabilize the key intermediates, thus enhancing dehydroxylation selectivity. This study demonstrates that tailoring the local electronic structure of Mo2C provides mechanistic insights and a potential design principle for achieving mild and selective deoxygenation of multifunctional α-hydroxyamide substrates.
己二酰胺（ADM）是各种聚酰胺和含氮精细化学品的重要中间体。然而，α-羟酰胺的选择性去羟基化仍然是催化脱氧中的一个重大挑战，因为脂肪族C-OH键的键解离能很高，并且酰胺基团具有明显的吸电子和分子内氢键作用。这些结构特征极大地稳定了分子框架，使得C-OH在常规氢脱氧（HDO）条件下难以活化，并经常导致不希望的C-N或C-C裂解。在这项工作中，设计了一系列n修饰的β-Mo2C催化剂，以促进2-羟基己二胺（2-HADM）的氢化去羟基化（HDH）为生物基adm。结构表征表明，氮的掺入在Mo2C晶格内形成间隙Mo - n -Mo环境，从而调节Mo位点的电子结构和酸碱性质。优化后的β-Mo2C-N-650催化剂在150℃、4 MPa H2条件下对ADM的转化率为33.2% %，选择性为92.0 %。密度泛函理论（DFT）计算进一步表明，氮掺杂可以降低C-OH键断裂的过渡态势垒，稳定关键中间体，从而提高脱羟基的选择性。该研究表明，定制Mo2C的局部电子结构为实现多功能α-羟酰胺底物的轻度选择性脱氧提供了机制见解和潜在的设计原则。
{"title":"Highly selective hydrodehydroxylation of 2-hydroxyadipamide to bio-based adipamide over N-doped Mo2C catalysts","authors":"Zhengxiang Ma , Yanhua Zhang , Qian Zhao , Liya Gao , Dongsheng Zhang , Xinqiang Zhao , Yanji Wang","doi":"10.1016/j.apcata.2026.120800","DOIUrl":"10.1016/j.apcata.2026.120800","url":null,"abstract":"<div><div>Adipamide (ADM) is an important intermediate for various polyamides and nitrogen-containing fine chemicals. However, the selective dehydroxylation of α-hydroxyamides remains a significant challenge in catalytic deoxygenation, due to the high bond dissociation energy of aliphatic C–OH bonds and the pronounced electron-withdrawing and intramolecular hydrogen-bonding effects of the amide groups. These structural features greatly stabilize the molecular framework, making C–OH activation difficult under conventional hydrodeoxygenation (HDO) conditions and often leading to undesired C–N or C–C cleavage. In this work, a series of N-modified β-Mo<sub>2</sub>C catalysts were designed to promote the hydrodehydroxylation (HDH) of 2-hydroxyadipamide (2-HADM) to bio-based ADM. Structural characterizations reveal that nitrogen incorporation forms interstitial Mo–N–Mo environments within the Mo<sub>2</sub>C lattice, thereby tuning the electronic structure and acid–base properties of Mo sites. The optimized β-Mo<sub>2</sub>C-N-650 catalyst achieves a 33.2 % conversion and 92.0 % selectivity to ADM at 150 °C and 4 MPa H<sub>2</sub>. Density functional theory (DFT) calculations further suggest that nitrogen doping may lower the transition-state barrier for C–OH bond scission and stabilize the key intermediates, thus enhancing dehydroxylation selectivity. This study demonstrates that tailoring the local electronic structure of Mo<sub>2</sub>C provides mechanistic insights and a potential design principle for achieving mild and selective deoxygenation of multifunctional α-hydroxyamide substrates.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"713 ","pages":"Article 120800"},"PeriodicalIF":4.8,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-01-21DOI: 10.1016/j.apcata.2026.120798
Yanke Huang , Pengzhen Yin , Xingtao Zhao , Fengqi Zhang , Huibing Shi , Zhaozhan Wang , Chen Li , Xufeng Lin , Yong Yang
Developing ligand-free heterogeneous catalysts capable of efficient and selective hydroformylation of sterically hindered alkenes remains a challenge. In this work, we report a stable and highly efficient ligand-free heterogeneous catalyst comprising atomically dispersed Rh sites anchored on N-doped SiO2. The N-doped SiO2 support was synthesized through a sol-gel method followed by high-temperature calcination under an inert atmosphere, endowing it with a large surface area, hierarchical pores, and tunable nitrogen content. This support facilitates the atomic dispersion and stabilization of Rh sites via strong Rh-N bond coordination. The morphological structure and local environment of single-Rh sites was comprehensively characterization by means of X-ray diffraction (XRD), N2 sorption isotherm, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), high-angle angular dark field scanning transmission electron microscopy (HAADF-STEM), X-ray photoelectron spectroscopy (XPS), CO in-situ diffuse reflectance infrared Fourier transform spectroscopy (CO-DRIFTS), and X-ray absorption spectroscopy (XAS). The resulting catalyst exhibits outstanding catalytic performance and excellent selectivity in the hydroformylation of diisobutylene and also shows broad applicability to various other alkenes, including α-olefins, internal alkenes, and aromatic alkenes. Furthermore, it exhibits remarkable stability and recyclability, maintaining its catalytic performance without degradation upon successive cycles. Comparative studies further confirm the essential role of N-doping in achieving high activity and stability.
{"title":"An atomically dispersed Rh catalyst on nitrogen-doped silica for hydroformylation of sterically hindered diisobutylene","authors":"Yanke Huang , Pengzhen Yin , Xingtao Zhao , Fengqi Zhang , Huibing Shi , Zhaozhan Wang , Chen Li , Xufeng Lin , Yong Yang","doi":"10.1016/j.apcata.2026.120798","DOIUrl":"10.1016/j.apcata.2026.120798","url":null,"abstract":"<div><div>Developing ligand-free heterogeneous catalysts capable of efficient and selective hydroformylation of sterically hindered alkenes remains a challenge. In this work, we report a stable and highly efficient ligand-free heterogeneous catalyst comprising atomically dispersed Rh sites anchored on N-doped SiO<sub>2</sub>. The N-doped SiO<sub>2</sub> support was synthesized through a sol-gel method followed by high-temperature calcination under an inert atmosphere, endowing it with a large surface area, hierarchical pores, and tunable nitrogen content. This support facilitates the atomic dispersion and stabilization of Rh sites via strong Rh-N bond coordination. The morphological structure and local environment of single-Rh sites was comprehensively characterization by means of X-ray diffraction (XRD), N<sub>2</sub> sorption isotherm, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), high-angle angular dark field scanning transmission electron microscopy (HAADF-STEM), X-ray photoelectron spectroscopy (XPS), CO in-situ diffuse reflectance infrared Fourier transform spectroscopy (CO-DRIFTS), and X-ray absorption spectroscopy (XAS). The resulting catalyst exhibits outstanding catalytic performance and excellent selectivity in the hydroformylation of diisobutylene and also shows broad applicability to various other alkenes, including α-olefins, internal alkenes, and aromatic alkenes. Furthermore, it exhibits remarkable stability and recyclability, maintaining its catalytic performance without degradation upon successive cycles. Comparative studies further confirm the essential role of N-doping in achieving high activity and stability.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"713 ","pages":"Article 120798"},"PeriodicalIF":4.8,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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