Sustainable Energy & Fuels最新文献

The development of sustainable photocatalysts for solar to hydrogen (STH) remains a central challenge in clean energy research. Here, binder-free Cu-doped TiO₂ nanosheets on conductive carbon cloth (Cu-TNS@CC) are fabricated and tested as a photocatalyst for STH. The optimized Cu-TNS@CC delivers a hydrogen evolution rate of 1765 µmol g⁻¹ h⁻¹, nearly seven times higher than that of pristine TiO₂@CC. Spectroscopic and structural analyses reveal the first evidence of a dynamic Cu⁰ ⇌ Cu⁺ ⇌ Cu²⁺ self-healing redox loop on any substrate, which leads to regeneration of active Cu₂O and prevents its deactivation with >98% stability over 20 hours of operation. These findings provide insightful knowledge of a redox self-healing Cu photocatalyst platform for sustainable solar hydrogen production.

Electrochemically oxidizing ethanol to acetate at the anode represents a promising alternative to the oxygen evolution reaction, enabling energy-efficient hydrogen evolution at the cathode. Herein, bimetallic NiMnO_x composites were synthesized via a hydrothermal method using nickel nitrate and potassium permanganate as precursors. Detailed electrochemical tests showed that 5NiMnO_x exhibited optimal ethanol oxidation reaction (EOR) activity (net current density: 8.8 mA cm⁻²) and a maximum acetate faradaic efficiency (FE) of 81.4% at 1.6 V vs. RHE, with stable performance over 12 h. DFT calculations demonstrated Ni doping modulates electronic structures, shifting Mn 3d bands toward the Fermi level and reducing the EOR rate-determining step barrier from 4.95 eV (pristine MnOOH) to 3.10 eV. Together, these insights highlight the potential of nickel–manganese oxides as cost-effective and stable catalysts for integrated hydrogen production and biomass-derived chemical manufacturing.

To realize green, high-value recycling of spent lithium-ion battery electrolytes and avoid isocyanate-based polyurethane toxicity, this study developed a non-isocyanate route for the green synthesis of thermoplastic polyurethane (TPU) via waste utilization. The low-boiling electrolyte-derived substances reacted with aromatic diamines as hard-segment diamino carboxylate precursors, while the high-boiling components condensed with dimethyl succinate (DMSu) to yield four hydroxyl-terminated polyethylene succinate (PES) prepolymers (M_η: 518.26, 1007.98, 1534.77, and 2023.62 g mol⁻¹) by adjusting the reaction time. A green catalyst system consisting of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and sodium methoxide (2 : 2 : 1) produced eight unmodified non-isocyanate TPUs, with the PES-2-based sample showing the best overall performance despite its insufficient tensile strength. Orthogonal experiments using ethylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, and renewable isosorbide (ISB) as chain extenders optimized the modification process, generating high-performance products 1,8-TPU-17 and 1,4-TPU-18. Characterized by FT-IR spectroscopy, ¹H/¹³C NMR, GPC, DSC, TGA, universal testing machine, DMA, and Materials Studio simulations, TPU had the expected structure, including T_g values of −19.36 to −20.56 °C, T_d,5% values of 184.09 to 253.64 °C, tensile strength values of 16.31 to 17.36 MPa, and elongation at break values of 438% to 451%. Isosorbide boosted chain rigidity, cohesive energy, and hydrogen bond density, with “O–H⋯OC” bonds supporting performance improvement. This work combines waste recycling and green polymer synthesis, offering eco-friendly and industrially scalable solutions.

Hydrazine-coupled electrolysis (OHzS) offers an energy-efficient route for hydrogen production by replacing the sluggish oxygen evolution reaction (OER) with the faster hydrazine oxidation reaction (HzOR, E° = −0.33 V vs. Reversible Hdrogen Electrode (RHE)). This approach significantly lowers cell voltage and yields environmentally benign byproducts (N₂ and H₂O), making it promising for green energy applications. However, the multistep proton-coupled electron transfer process in HzOR necessitates the development of highly active, stable, and cost-effective electrocatalysts. Nickel-based materials stand out due to their earth abundance, tunable Ni²⁺/Ni³⁺ redox chemistry, excellent conductivity, and strong hydrazine affinity. This review summarises recent advances in Ni-based catalysts, including alloys, oxides, hydroxides, phosphides, nitrides, chalcogenides, and MOFs, emphasising synthesis strategies, hierarchical architectures, and key activity enhancement mechanisms such as synergistic effects, electronic structure modulation, defect engineering, and interfacial coupling. Insights from experiments and Density Functional Theory (DFT) calculations are discussed to elucidate reaction pathways and guide bifunctional catalyst design for concurrent HzOR and HER. Additionally, the integration of machine learning (ML) is highlighted as a promising approach to accelerate catalyst discovery and optimisation. We conclude with future directions toward scalable, high-performance, and low-voltage hydrogen generation by uniting mechanistic understanding, materials design, and predictive modelling.

This study investigates the suitability of all-inorganic halide perovskites of CsPbI₂Br for space applications with an emphasis on their thermal stability under the simulated Low Earth Orbit (LEO) space conditions. The substrate pre-heating is found to play a critical role in obtaining ambient stable CsPbI₂Br perovskite solar cells. The in situ photovoltaic properties of the CsPbI₂Br solar cells over a broad temperature range (+150 °C to −150 °C) and under combined stressors such as heat, vacuum, and AM0-like illumination were systematically investigated for both glass/ITO and fused silica/ITO substrates. The extent of performance loss and recovery is found to be strongly determined by the choice of substrates, with the fused silica/ITO-based devices showing relatively better performance recovery than the glass/ITO-based devices, after 24 h. Microstructural analysis of partial device heterostructures shows that CsPbI₂Br films on fused silica retain their crystalline phase, preferred orientation, and optical absorption even under extreme temperature fluctuations, indicating better thermal compatibility. Overall, this study highlights the significance of substrate engineering in enhancing the durability of CsPbI₂Br perovskite solar cells for space applications.

Water splitting is a promising way to generate H₂ for a sustainable future. However, developing cost-effective bifunctional electrocatalysts for water electrolysis and seawater electrolysis (interference of corrosive Cl₂ evolution) is still challenging. Based on that, we synthesized interfacially coupled metal oxides (NiFe₂O₄, NiO, and Fe₂O₃) embedded with nitrogen-doped carbon (N@C) by a cost-effective mechanochemical and calcination process, which exhibited highly efficient bifunctional activity and long-term stability towards overall water splitting. The three heterophase metal oxides with electrochemical active sites and nitrogen-doped carbon create a strong interfacial coupling effect that synergistically enhances the rapid electron transfer into the system. Furthermore, the porous carbon layers facilitate charge transport during electrocatalysis, thereby promoting active site exposure during electrolysis. N@C-Ni_1.2-Fe_0.5 shows a low overpotential and Tafel slope of 310 mV & 80 mV dec⁻¹ for the OER and 104 mV & 98 mV dec⁻¹ for the HER in 1 M KOH at 10 mV cm⁻² (without iR correction). N@C-Ni_1.2-Fe_0.5 exhibits 25 h long-term stability for the OER and HER with a low potential loss of about 2.4% and 2.8%. N@C-Ni_1.2-Fe_0.5 shows a low overpotential of 341 mV for the OER and 146 mV for the HER in 1 M KOH + natural seawater. N@C-Ni_1.2-Fe_0.5//N@C-Ni_1.2-Fe_0.5 exhibits an overall water splitting cell voltage of 1.63 V, 1.65 V, and 1.68 V in 1 M KOH, 1 M KOH + 1 M NaCl, and 1 M KOH + seawater. Additionally, a homemade water electrolyzer (N@C-Ni_1.2-Fe_0.5//N@C-Ni_1.2-Fe_0.5) was powered by conventional and renewable solar energy for generating H₂. Furthermore, the generated green H₂ was utilized to power a DC motor.

Polymer electrolyte membranes used in proton exchange membrane water electrolysis (PEMWE) must simultaneously exhibit high proton conductivity, chemical durability, and structural stability under strongly oxidative operating conditions. However, many hydrocarbon-based membranes contain ether linkages that are susceptible to radical-induced degradation, limiting their long-term stability. Herein, an ether-free polybenzimidazole (PBI) framework containing fluorinated hexafluoroisopropylidene units was engineered to improve oxidative robustness while maintaining membrane processability. To enhance proton transport, the polymer backbone was functionalized via side-chain grafting of 1,4-butane sultone, introducing sulfonated hydrophilic domains capable of forming hydrogen bonded water network for proton-conduction. The resulting membranes (FPBI-g-BS-x) were systematically investigated in terms of physicochemical, thermal, and electrochemical properties. Among the fabricated membranes, FPBI-g-BS-43 exhibited the highest ion-exchange capacity (2.28 ± 0.21 meq g⁻¹), water uptake (40.6 ± 2.08), and proton conductivity (5.22 ± 0.54 mS cm⁻¹ at 40 °C). Morphological studies revealed well-developed nanophase separation with interconnected ionic clusters facilitating proton transport. Importantly, the ether-free PBI backbone demonstrated excellent thermal stability (>400 °C) and strong resistance to oxidative degradation, highlighting the structural advantage of this architecture. In a single-cell PEM water electrolyzer operating at 80 °C, FPBI-g-BS-43 delivered a current density of ∼649 mA cm⁻² at 1.8 V, outperforming Nafion® 117 under identical conditions. These results demonstrate that side-chain engineering of ether-free PBI membranes provides an effective strategy to balance proton conductivity and chemical durability, offering an efficient hydrocarbon-based alternative to perfluorinated membranes for PEMWE applications.

This study explores a metabolically versatile and thermotolerant Aspergillus terreus BD isolate, which exhibited selective itaconic acid (IA) and L-malic acid (L-MA) production under distinct fermentation conditions at 45 °C. An acidic fermentation medium (pH 3.4) with an inorganic nitrogen source favoured predominant IA synthesis. Contrastingly, organic nitrogen supplementation in a near-neutral medium (pH 6.0) diverted the metabolic flux towards L-MA. Relative gene expression analysis supported the differential IA and L-MA production under selective media conditions, showing upregulation of key genes in their respective biosynthetic pathways. Furthermore, the isolate was employed for the valorization of waste potato biomass (WPB), which is a major food waste worldwide. Fermentation of the enzymatic WPB hydrolysate at 45 °C generated a substantial L-MA titer (37 g L⁻¹) without requiring CaCO₃ supplementation. Operating at elevated temperatures reduces cooling demands, minimizes contamination risks, and improves compatibility with saccharification conditions. Eliminating CaCO₃ minimizes chemical inputs and neutralization sludge outputs, thereby lowering the environmental burden and downstream complications. Harnessing these significant attributes, the isolate was integrated into a one-pot bioprocess employing simultaneous and semi-simultaneous saccharification and fermentation approaches. Process optimization, including solid loading, pH, inoculum size, pre-hydrolysis time, and enzyme dosage, yielded 60 g L-MA per kg WPB. Finally, extraction using n-butanol led to the recovery of 58% L-MA. Overall, these findings present A. terreus BD, integrated into an efficient one-pot bioprocess, as a promising platform for the sustainable and economically viable production and recovery of L-MA from starch-rich agro-industrial waste.

Nickel–iron layered double hydroxide (NiFe LDH) is considered as a promising catalyst for the oxygen evolution reaction (OER) during water splitting. However, its application in large-scale seawater electrolysis is limited by poor electrical conductivity, insufficient exposure of active sites, and the competing chlorine evolution reaction in seawater. The multiple limitations are addressed through effective Ce doping in quasi-parallel NiFe LDH (NiFeCe LDH) nanosheet arrays on a Ni foam substrate. The introduction of Ce induces the formation of nanoarrays with open spacing, and the frustrated Lewis pairs (FLPs) induced by the Ce 4f-O 2p interaction lead to the enrichment of high-valence Ni active phases and stabilization of Fe sites, which significantly enhances OER performance. The NiFeCe LDH electrode can achieve a high current density of 500 mA cm⁻² with overpotentials of 262 and 288 mV in 1.0 M KOH and alkaline simulated seawater (1.0 M KOH + 0.5 M NaCl), respectively, and remain stable for 600 h at 500 mA cm⁻² in alkaline seawater without potential decay. This work provides new insights into electronic modulation and activity optimization of nickel-iron-based electrocatalysts.

This study presents a comprehensive techno-economic and environmental assessment of an integrated solar-powered green hydrogen system designed to decarbonize energy use at a large private university campus in Bangladesh. The research addresses the growing need for sustainable institutional energy solutions in developing South Asian regions, where rising electricity demand and diesel dependency contribute significantly to greenhouse gas emissions. To bridge this gap, the study proposes a 6.25 MWp photovoltaic array coupled with a 5 MW proton exchange membrane electrolyzer, targeting simultaneous fulfillment of on-site electricity demand (1015 MWh per year) and transport fuel substitution (504 000 L diesel per year). A novel unified dual-vector institutional architecture is introduced, integrating electricity and hydrogen systems using a seasonal demand superposition approach to optimize system design within a 1–10 MW capacity range. Methodologically, the study advances system sizing accuracy through the introduction of a solar window capacity factor (95.3%), which corrects a 4.80× underestimation inherent in the conventional annual capacity factor (19.9%). A tropical grid-specific energy management system model, developed using 13 months of institutional operational data, demonstrates 98.5% autonomous reliability and achieves 42% energy cost savings during off-peak periods. Economic feasibility is evaluated using a co-product revenue-based levelized cost of hydrogen framework, incorporating dual weighted average cost of capital scenarios and Monte Carlo simulations (10 000 iterations across 12 variables). The results highlight concessional financing as a key enabler: the levelized cost decreases from $5.50 ± 0.70/kg at 8% WACC (with a net present value of −$7.23 million) to $3.09 ± 0.52/kg at 4% WACC (NPV −$0.23 million), significantly improving viability. An ISO-compliant lifecycle assessment reveals total emissions of 12 089 tCO₂e, with a carbon payback period of 8.17 years within a 20-year project lifespan and a net lifecycle reduction of 17 520 tCO₂e, corresponding to 59.2% emission reduction efficiency. The proposed methodologies offer a flexible and scalable framework for institutional adoption of green hydrogen systems, contributing both to decarbonization goals and to the broader transition toward sustainable energy systems in developing economies.