ACS Applied Energy Materials最新文献

A series of machine learning (ML) investigations were performed to validate experimentally obtained thermoelectric (TE) property trends and guide composition-property exploration in the Zintl-phase Ba_1–xSr_xZn_2–yMn_ySb₂ system. As an experimental test case, the three Mn or Sr/Mn-substituted BaCu₂S₂-type compounds, BaZn_1.83(3)Mn_0.17Sb₂, BaZn_1.71(3)Mn_0.29Sb₂, and Ba_0.88(1)Sr_0.12Zn_1.75(3)Mn_0.25Sb₂, were successfully synthesized and structurally characterized by powder and single-crystal X-ray diffraction analyses. Their phase selectivity for the BaCu₂S₂-type phase was consistent with the r₊/r_– radius ratio criterion, and temperature-dependent transport property measurements confirmed the p-type behavior of the title materials. Given that the Mn or Sr/Mn substitutions systematically altered the balance between S and σ, the title system was considered as a useful benchmark for the ML-based trend validation for TE properties. Therefore, a customized TE dataset containing 5923 temperature-dependent entries from 949 materials was then constructed to train the three ML models for σ, S, and κ_tot predictions. First, seven different regression algorithms were comprehensively evaluated based on a coefficient for determination values, and XGBRegressor was selected for the further analysis since it offered the best balance between predictive accuracy and computational efficiency. The selected models were rigorously assessed using 10-fold cross-validation, residual and error analyses, learning curves, bootstrapped uncertainty estimation, Shapley additive explanations, and partial dependence plot/individual conditional expectation curve analyses of temperature-dependent property responses. The ML models reproduced the experimental performance hierarchy, correctly identifying BaZn₂Sb₂ as the highest PF compound among the studied samples. The 2-dimensional composition-property contour maps further predicted that moderate Sr substitution may lower κ_tot and improve projected ZT, indicating the Ba-rich/Sr-substituted BaZn₂Sb₂ derivatives as data-guided targets for future experimental optimization.

The electrocatalytic nitrogen reduction reaction (NRR) is a valuable green route for ammonia synthesis, yet it is still constrained by the lack of efficient catalysts and the impact of the competing hydrogen evolution reaction (HER). Density functional theory (DFT) is applied to explore the NRR and HER behaviors of metal single atoms embedded in pyridinic-N₄-modified divacancy-defected BC3 monolayer structures (M-SACs@BC3) and reveal the underlying modulation mechanisms. DFT results suggest that Mo-SACs@BC3 delivers favorable NRR activity with a low limiting potential (U_L) of –0.46 V while inhibiting the HER. In comparison, Tc-SACs@BC3 shows considerable HER activity, with its hydrogen adsorption free energy (ΔG_H*) approaching –0.10 eV. Electronic structure analysis indicates that the high activity originates from strong orbital coupling between metal d-orbitals and reaction intermediates, as well as efficient charge transfer between the substrate and the metal sites. Random forest (RF) machine learning (ML) models are constructed to predict adsorption free energies for key NRR intermediates and ΔG_H* for HER. The model exhibits good prediction capability on an external DFT- and literature-based dataset for rapid data-driven catalyst screening. This work offers theoretical insights for the rational design of BC3-based single-atom catalysts for NRR and HER.

Thermoelectric generators (TEGs) enable direct conversion of waste heat into electrical energy. Although Bi₂Te₃-based alloys have long been the conventional thermoelectric materials, concerns over their toxicity and limited availability have encouraged the development of sustainable alternatives. This study presents a tellurium-free TEG module based on optimized n-type Mg₃(Sb, Bi)₂, a solid solution of Mg₃Sb₂ and Mg₃Bi₂, and p-type MgAgSb as promising alternatives to conventional Bi₂Te₃-based thermoelectric materials. Both materials were synthesized using scalable vacuum-melting methods and exhibited enhanced thermoelectric performance, which was attributed to improved weighted mobility and reduced lattice thermal conductivity. Low-resistance metallic contacts with a specific contact resistivity of approximately 15–20 μΩ·cm² were successfully fabricated on both materials using a “monobloc” sintering method. An 11 p−n couple TEG module fabricated from these materials achieved a conversion efficiency of approximately 7.1% at a temperature difference of 250 K, in good agreement with simulation predictions. Moreover, at a temperature difference of 300 K and a hot end temperature of approximately 603 K, the TEG module achieved a conversion efficiency of approximately 8.5%, surpassing the performance of state-of-the-art Bi₂Te₃-based modules under comparable operating conditions.

Au/TiO₂ is a promising photocatalyst for CO₂ reduction, yet its performance is often limited by inefficient light utilization and insufficient local CO₂ availability. Here, we present an integrated photocatalytic platform by embedding Au/TiO₂ nanoparticles within imidazolium poly(ionic liquid) (PIL) nanocone arrays. The nanocone architecture provides broadband light harvesting with > 99% absorptivity, while the imidazolium PIL enriches CO₂ near the catalytic sites, enabling synergistic enhancement of CO₂ photoreduction. The intrinsic counter-anion exchangeability of the PIL further enables programmable regulation of the overall catalytic activity and product formation selectivity. By optimizing the counter anion and water supply, the system selectively produces CO (124.89 μmol·g^–1·h^–1, 94.2% selectivity) or CH₄ (137.75 μmol·g^–1·h^–1, 100% selectivity). Metalloporphyrin counter anions additionally enable C2 product formation, while functional catalytic anions allow cascade conversion of CO₂ into polymeric products. This work demonstrates an integrated strategy that couples light management, substrate enrichment, and reaction programmability for efficient and versatile solar-driven CO₂ conversion.

Carbon dioxide (CO₂) fixation is an innovative approach to address the challenges of climate concerns and sustainable energy systems. The utilization of CO₂ as an abundant and renewable carbon source in carboxylation reactions offers an attractive and sustainable strategy to access high-value-added carboxylic acids. In this context, the direct C–H carboxylation of terminal alkynes with CO₂ has gained significant attention for the rapid synthesis of propiolic acids. However, achieving efficient C(sp)–H carboxylation of terminal alkynes under mild conditions remains a significant challenge. Herein, we report the carboxylation of the C(sp)–H bond in aromatic terminal alkynes with CO₂ at room temperature and atmospheric pressure using a highly efficient silver nanoparticles (Ag)-embedded β-ketoenamine-linked covalent organic framework (Tp-APB@Ag) film as a photocatalyst under solar light irradiation. Remarkably, the as-synthesized Tp-APB@Ag film photocatalyst achieved an impressive aromatic propiolic acid formation as high as 99.9% yield and 100% selectivity. Additionally, the photocatalyst demonstrated outstanding recyclability without significant loss in catalytic activity and structural integrity. Moreover, this sustainable and economic carboxylation strategy exhibited mild reaction conditions, good functional group tolerance, and a broad scope across various reactants. This work not only enables the rational molecular-level engineering of advanced photocatalysts but also provides in-depth insights for efficient CO₂ transformation into valuable commodity chemicals at ambient conditions.

Using a developed parallelized solid-dispensing platform, we screened in situ modified TiO₂ photocatalysts for visible-light-driven carbohydrate reforming coupled with hydrogen evolution. Across eleven monometallic and eighteen bimetallic catalyst combinations, Cu-TiO₂ emerged as the most promising earth-abundant system. Expanded screening of Cu-TiO₂ across seven simple carbohydrates, three polysaccharides, three fruit juices, and two forms of cotton revealed strong donor-dependent reactivity, with maltose and cellulose yielding the highest hydrogen evolution among the soluble sugars and complex carbohydrates, respectively. Photon-normalized and mass-normalized activity metrics derived from ferrioxalate actinometry contextualize donor performance under visible-light irradiation. Glycerol was used to probe the oxidation half-reaction, and post-illumination analysis identified several established oxidation products, supporting coupled substrate oxidation during H₂ formation. XPS and Auger spectroscopy revealed that photodeposition yields a mixed-valence copper surface layer (Cu⁰/Cu⁺/Cu²⁺). UV–vis-NIR extinction and Tauc analysis demonstrated that Cu incorporation narrows the indirect band gap to enhance visible-light absorption. These results establish Cu-TiO₂ as a promising earth-abundant photocatalyst for biomass-coupled hydrogen evolution and show how parallelized screening can accelerate catalyst discovery and reveal structure-reactivity relationships in heterogeneous photocatalysis.

Donor-rich conjugated polymers are attractive photocatalysts owing to their strong light-harvesting capability, synthetic accessibility, and excellent processability. However, their photocatalytic performance is often limited by rapid excited-state relaxation and charge recombination. Here, we demonstrate a sparse acceptor strategy for regulating excited-state dynamics in donor-rich linear conjugated polymer nanoparticles. An alkoxy-poly(p-phenylene)-based polymer (PP) is modified with approximately 2 mol % benzothiadiazole (BT), thiophene-linked benzothiadiazole (DTBT), or thiophene-linked benzoselenadiazole (DTBSe) units and subsequently processed into aqueous nanoparticles through nanoprecipitation. Although all polymers retained donor-rich optical characteristics, sparse acceptor incorporation significantly influenced excited-state behavior. In particular, PP-DTBT exhibited spectroscopic signatures consistent with acceptor-mediated excited-state relaxation, prolonged photoluminescence lifetimes, and enhanced populations of long-lived photoexcited species. Transient spectroscopic analyses further revealed acceptor-mediated excited-state stabilization and Pt-mediated charge extraction under photocatalytic conditions. These characteristics were reflected in the photocatalytic performance, with PP-DTBT showing the highest hydrogen evolution activity of 1.2 mmol g^–1 h^–1, substantially outperforming the BT- and DTBSe-containing analogues. The results demonstrate that sparse acceptor incorporation can effectively regulate excited-state relaxation, generate long-lived excited states, and promote more favorable charge extraction and utilization pathways without disrupting the donor-rich nature of the polymer backbone. This work establishes sparse acceptor-site engineering as an effective strategy for controlling excited-state dynamics and enhancing photocatalytic hydrogen evolution in donor-rich polymer nanoparticles.

Unsaturated silicon oxide (SiO_x) as one of the anode materials for lithium-ion batteries (LIBs) shows relatively high specific capacity, but its overall electrochemical performances remain to be improved. Herein, a facile synthetic approach is developed to deposit SiO_x and amorphous carbon on spherical graphite particles getting core–shell structured graphite@SiO_x/C (SG@SiO_x/C) composites via tetraethyl orthosilicate and ascorbic acid as precursors. The homogeneous and dense SiO_x/C layer can improve the structural integrity of the SG@SiO_x/C anodes and afford the composites with manifest specific capacity for Li⁺ storage. To improve the initial Coulombic efficiency (ICE), the SG@SiO_x/C composites are further chemically prelithiated. The prelithiated SG@SiO_x/C exhibits an initial lithiation/delithiation capacity of 632.6/629.4 mAh g^–1 with a remarkable ICE of 99.5%. The reversible specific capacity can remain at 390.5 mAh g^–1 after 1000 cycles at a current density of 1C. This work offers technical guidance on how to synthesize high-performance graphite@SiO_x composites, providing a pathway to high-energy-density LIBs.

Sodium carboxymethyl cellulose (CMC) is a promising aqueous binder for graphite anodes, but its limited adhesion, poor Li⁺ transport, and interfacial instability hinder long-term performance. Herein, CMC was functionalized with lithium sulfate ester groups to obtain a multifunctional aqueous binder (CMCSL). The introduced –OSO₃Li groups strengthen interfacial interactions, improve electrolyte wettability, and facilitate Li⁺ transport, thereby preserving electrode integrity and promoting a thin, stable solid electrolyte interphase. Compared to 2.05 N for CMC and 1.33 N for PVDF, CMCSL reaches a peel force of 3.40 N, an ionic conductivity of 3.1 × 10^–3 mS cm^–1, and a Li⁺ diffusion coefficient of 7.14 × 10^–9 cm² s^–1. Consequently, the CMCSL-based electrode retains 265.43 mAh g^–1 after 1000 cycles at 1 C with 88.79% capacity retention and delivers 121.1 mAh g^–1 at 5 C. This work demonstrates an effective molecular-engineering strategy for developing durable aqueous binders with high adhesion, ion transport, and interfacial stability.

A solid solvent in salt concept is applied to all-solid-state batteries (ASSBs) using a soft solid electrolyte (SE) composed of lithium bis(trifluoromethanesulfonyl)imide, succinonitrile, and ethylene carbonate with a weight ratio of 85/11/4. The developed SE exhibits an ionic conductivity of ∼10⁻⁴ S/cm at room temperature and an electrochemical stability window of approximately 5 V. Electrochemical performance was evaluated using lithium, graphite, and SiO_X anodes paired with a LiFePO₄ (LFP) cathode. The ASSBs, including LFP/SE/SiO_X and LFP/SE/graphite configurations, demonstrates reversible cycling at room temperature without the application of external pressure, highlighting the potential of the soft SE for practical ASSB applications.