Sustainable Energy & Fuels最新文献

Barium titanate (BaTiO₃) has long been regarded as inactive for photocatalytic overall water splitting, in stark contrast to its perovskite counterparts SrTiO₃ and CaTiO₃. Here we report that BaTiO₃ codoped with Al³⁺ and Sc³⁺ at Ti⁴⁺ sites under flux synthesis conditions is activated as a robust photocatalyst for overall water splitting. This material achieves apparent quantum yields of 29.8% at 310 nm and 27.5% at 365 nm, representing the first demonstration of efficient overall water splitting on BaTiO₃. Comparative analyses show that BaTiO₃ doped only with Al³⁺ suffers from severe band-edge disorder, whereas BaTiO₃ codoped with Al³⁺ and Mg²⁺ exhibits clear activation with moderate efficiency. In contrast, BaTiO₃ codoped with Al³⁺ and Sc³⁺ achieves the critical defect and structural control required to push the material across the threshold from inactive to highly active. These findings overturn the long-standing perception of BaTiO₃ as unsuitable for water splitting and establish a general design principle for activating previously inactive perovskite oxides, thereby expanding the materials palette for solar-to-hydrogen energy conversion.

Wide band gap semiconductors are essential for next-generation photovoltaics, especially indoor tandem applications, because they align well with both the solar spectrum and artificial light sources. Quaternary chalcogenides, such as Cu₂ZnSnS₄ (CZTS), offer tunable bandgaps, stability, and earth abundance. In this study, Ag-alloyed CZTS (ACZTS) thin films were synthesized via a controlled chemical solution process involving spin coating deposition process and sulfur annealing. Elemental composition and morphology analyses confirmed uniform grain distribution and precise control of the Ag/Cu ratio. Structural characterization via X-ray diffraction and Raman spectroscopy revealed a gradual transformation from the kesterite to the stannite phase as the Ag concentration increased. This transformation was accompanied by lattice expansion and a change in crystallite size. Optical measurements showed a clear widening of the bandgap from approximately 1.5 eV of pure CZTS to about 1.7 eV at high Ag levels, supporting its potential use as a top absorber in tandem solar cells. These findings demonstrate that alloying with Ag effectively tailors the properties of CZTS, making it a promising, non-toxic candidate for stable and efficient use in solar cells for indoor environments or high-efficiency tandem applications.

Lithium nitrate (LiNO₃) exhibits exceptional solid electrolyte interphase-forming capabilities, cost efficiency, high thermal stability, and low environmental impact. However, its limited solubility in ester-based electrolytes means that it is frequently used only as an electrolyte additive. This study presents a low-concentration electrolyte (LCE) formulation comprising 1,2-dimethoxyethane (DME), fluoroethylene carbonate (FEC), and ethoxylated pentafluorocyclotriphosphazene (PFPN), with 0.5 M lithium nitrate (LiNO₃) serving as the sole lithium salt. In LiNO₃, strong Li⁺–NO₃⁻ interactions arise from the high binding affinity between NO₃⁻ and Li⁺, driving preferential incorporation of NO₃⁻ into the Li⁺ solvation shell to form a solvation structure dominated by contact ion pairs (CIPs). Furthermore, FEC and PFPN pull out part of DME from the Li⁺ solvation shell via intermolecular interactions, thereby reducing the proportion of DME solvent participation in the Li⁺ solvation shell and promoting the formation of nitrate-rich aggregates (AGG/AGG+). This design confers high voltage tolerance (4.4 V) and non-flammability characteristics to a 0.5 M low-salt-concentration ether-based electrolyte. It tackles the challenge inherent in LCEs, where solvent-dominated solvation architectures give rise to the formation of an organic-rich solid electrolyte interphase (SEI), culminating in suboptimal cycling stability. The approach markedly improves the cycling performance of NMC811 (9.2 mg cm⁻²)‖Li (50 μm) full cells, achieving 80% capacity retention after 150 cycles, while promoting the formation of a LiF/Li₃N inorganic composite solid electrolyte interphase (SEI). The key strategy of this work is to utilize LiNO₃ as the sole lithium salt, which paves a novel pathway for the rational design of advanced low-concentration electrolytes.

Metal halide perovskites are highly attractive for optoelectronic applications due to their exceptional optoelectronic properties. However, defect-induced non-radiative recombination and poor long-term stability continue to limit device performance. In this work, we present a Lewis base doping strategy using (4-(2,7-dibromo-9,9-dimethylacridin-10(9H)-yl)butyl)phosphonic acid (DMAcPA) to effectively passivate electron trap states in perovskite films. The phosphonic acid group in DMAcPA coordinates with undercoordinated Pb²⁺ ions, thereby suppressing trap-assisted recombination. This doping approach results in a 77% reduction in electron trap density, a fourfold enhancement in carrier lifetime, enlarged grain size, and improved film crystallinity. As a result, inverted (p–i–n) perovskite solar cells incorporating DMAcPA achieve a power conversion efficiency of 24.22% and exhibit excellent ambient stability, retaining 81% of their initial efficiency after 60 days. These findings demonstrate the potential of molecular-level doping with phosphonic acid-functionalized compounds as a general strategy for defect mitigation and performance enhancement in perovskite photovoltaics.

The alkaline hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) are gaining considerable interest for boosting the overall water splitting in the context of green hydrogen production with simultaneous urea removal from wastewater. In this work, we successfully synthesized a novel cobalt-based two-dimensional (2D) metal–organic framework (MOF), named Co-IDBA-MOF, by a solvothermal method using a mixed ligand system consisting of 2,2′-iminodibenzoic acid (IDBA) and 4,4′-bipyridine (Bpy). Single-crystal X-ray analysis of the Co-IDBA-MOF confirmed its layered 2D structure. The bulk specimen of the MOF was further characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric (TG) analysis, and UV-visible spectroscopic analysis. Field emission-scanning electron microscopic (FE-SEM), field emission gun-transmission electron microscopic (FEG-TEM) and atomic force microscopic (AFM) analyses uncovered the ultrathin 2D nanosheet-type morphology of the MOF, which facilitates the fabrication of 2D materials for the potential fabrication of real devices. This Co-IDBA-MOF exhibited good electrocatalytic performance in the alkaline HER at −0.241 V w. r. t. RHE at a current density of 10 mA cm⁻² (η₁₀) and a modest oxygen evolution reaction (OER) activity (1.66 V for 10 mA cm⁻² w. r. t. RHE) in an alkaline water medium. However, the anodic potential got drastically reduced to 1.55 V after the addition of 0.33 M urea due to the urea oxidation reaction (UOR). The lowering of the Tafel slope and the concomitant increase in double-layer capacitance for the alkaline hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) suggested improved kinetics for overall water splitting after urea addition. Further variations in the urea concentration and the concentration of electrode materials can tune the UOR activity. This work aims to design a novel Co-MOF-based electrode material for bifunctional activity and large-scale green hydrogen production via the UOR.

We investigate the use of hydrolysate from preconditioned pine wood chips using dilute sulfuric acid for biofuel production. High-performance liquid chromatography analysis of the hydrolysate indicated the presence of pentoses, hexoses, and various degradation products, including levulinic acid, furfural, and hydroxymethylfurfural. Both detoxified and non-detoxified lignocellulosic hydrolysates were examined for lipid production (biofuel intermediates) using the oleaginous strain Cutaneotrichosporon curvatus. After five days of growth, C. curvatus achieved a maximum dry cell weight of 0.93 g per g of mixed sugars and a lipid yield of 0.23 g per g of mixed sugars. The lipid content represented 25% of the dry cell weight, suggesting that C. curvatus is a promising alternative for utilizing both C5 and C6 sugars derived from pretreated lignocellulosic biomass. Hydrothermal liquefaction of the C. curvatus broth was conducted under subcritical and supercritical water conditions. The bio-oil was extracted using dichloromethane, and the calculated higher heating values of the bio-oil were found to be 26.4, 34.4, and 37.2 MJ kg⁻¹ at 300 °C, 350 °C, and 375 °C reaction temperatures, respectively. The composition of biocrude was analyzed using GC-MS and identified oleic, palmitic, stearic, pentadecanoic, palmitic, and heptadecanoic acids. The results of this study demonstrate an integrated pathway with the potential to upgrade a mixed sugar stream into fuel intermediates.

Solar photothermal chemical fuels collect and store solar energy through molecular structure changes and release the stored energy in the form of heat. Molecular software was used to construct molecular models of azobenzene and azobenzene–graphite-like phase carbon nitride (AZO–g-C₃N₄), and structure optimization and energy calculations were carried out on the models based on density functional theory. The isomerization recovery time of azobenzene is prolonged by grafting g-C₃N₄, and its energy is increased by 0.87–1.50 eV compared with that of the pre-grafting model. Four azobenzene monomers with different structures were experimentally designed to be grafted onto g-C₃N₄ templates to form AZO–g-C₃N₄ hybrid materials. Compared with that of the original azobenzene, the half-life of the grafted g-C₃N₄ increased from 4 h, 6 h, 12 h, and 15 h to 57 h, 82 h, 164 h, and 223 h, respectively; the thermal stability of the grafted AZO–g-C₃N₄ material was improved by 77–171%, and the energy density reached 32.15 Wh kg⁻¹, 39.6 Wh kg⁻¹, 60.3 Wh kg⁻¹, and 75.79 Wh kg⁻¹, respectively, with high thermal storage and release capability. Results show that the use of azobenzene-grafted g-C₃N₄ templates is an effective method to improve the half-life, thermal stability, and energy storage density of solar fuel recovery systems.

Hydrogen production via water electrolysis using renewable energy sources has attracted significant attention as a promising pathway toward a sustainable society. The development of cost-effective and highly active oxygen evolution reaction (OER) catalysts will be an essential aspect of improving the efficiency of such systems. The present study demonstrates an OER electrocatalyst obtained from the ball milling of naturally occurring manganese nodules. This material was found to exhibit catalytic activity during the OER. X-ray diffraction data suggested that the crystal structure of the manganese nodules was similar to that of todorokite-type δ-MnO₂. Mn K-edge X-ray absorption fine structure (XAFS) analyses indicated that the Mn valence state in the nodules changed from Mn⁴⁺ to Mn³⁺ during the ball-milling process, accompanied by disordering of the fine crystal structure. Operando XAFS experiments also established that Mn³⁺ in this material was partially oxidized during the OER. On this basis, a disordered δ-MnO₂ phase containing Mn³⁺ is thought to have provided active sites for water oxidation.

Mesoporous nanomaterials and nanohybrids have grabbed the attention of researchers for supercapacitor applications with their unique structural attributes and enhanced electrochemical properties. Recent developments have focused on optimizing the synthesis process and functionalization to achieve higher specific surface areas, tailored pore structures, and improved conductivity. These advancements are important for regular improvements in power density, cycling stability, and energy density of supercapacitors. Regardless of this, the challenges remain, particularly in the scalability of synthesis processes; the integration of nanohybrids with diverse materials enhances the long-term cycling stability under practical operating conditions. Prospects are promising, with ongoing research directed towards novel material combinations, advanced fabrication techniques, and the development of environmentally sustainable processes. Emerging trends suggest that the integration of technology could further accelerate the design and optimization of mesoporous nanomaterials and nanohybrids for developing future supercapacitors. This review article focuses on the theoretical and fundamental aspects of charge storage mechanisms for supercapacitor applications with respect to mesoporous nanomaterials and nanohybrids.

Improving the catalytic performance in the hydrodeoxygenation (HDO) of lignin oils to produce liquid fuels, while meeting industrial requirements, is important for addressing current environmental challenges. In the present study, the promoting effects of noble metals (Pd, Pt, and Ir) on the performance of the Ni–Mo/CeLa/Al₂O₃ catalyst were investigated in the HDO of a lignin-derived pyrolysis oil. Catalysts were prepared using incipient wetness impregnation, where 0.5 wt% of the noble metals were impregnated on the catalyst in a final, subsequent step. The HDO experiments were conducted either without or with dimethyl disulfide (DMDS) in a batch reactor at 320 °C and 50 bar (initial H₂ pressure at room temperature) for three hours. Interestingly, the highest deoxygenation degree was achieved over the reference catalyst when DMDS was added, in which the resulting oil contained approximately 60% aliphatic and phenolic compounds. Pt showed the most promising promoting effect, which is inferred from its improved hydrogenation capability.