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Light irradiation enhanced CO2 reduction with methane: A case study in size-dependent optical property of Ni nanoparticles
摘要： Ni/Al2O3 catalysts and bulk Ni nanoparticles, with the average sizes of Ni particles varying from 2.7 nm to 238.0 nm, were synthesized and evaluated in CO2 photoreduction with methane (CRM). It was found that the catalytic activities of the Ni-based catalysts were all increased almost linearly with light intensity in the range of 0–1.07 W cm?2, with the optical properties of Ni particles being regarded to account for the activity enhancement. Wavelength dependent performance study suggested that Ni LSPR dominated for the optical property of smaller Ni nanoparticles whereas interband transition played gradually increased role in improving the activities over larger Ni particles. To the best of our knowledge, it is the first time to study the size-dependent optical properties of Ni nanoparticles, meanwhile, this study offers a foundation to further improve the efficiency of Ni-based catalysts in CO2 utilizations.
关键词： Ni nanoparticles,Interband transition,CO2 photoreduction,Localized Surface plasmon resonance,Photocatalysis
更新于2025-09-10 09:29:36
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Influence of defects in porous ZnO nanoplates on CO2 photoreduction
摘要： Photocatalytic conversion of CO2 into hydrocarbons by utilization of the solar energy is considered a promising approach to mitigate energy crisis and the environmental issues. Since the defects in a catalyst play an important role in CO2 reduction, herein, the porous ZnO nanoplates with vacancy defects are synthesized by annealing ZnS(en)0.5 precursor in air at different temperature. The defect amount in ZnO changes with the annealing temperature, resulting in different photocatalytic activity for CO2 reduction. The related mechanism has been studied both experimentally and theoretically. Raman spectra and chemical composition of the obtained catalysts are used to determine the defects. Transient techniques are used to investigate the separation of photogenerated charge carriers. CO2 adsorption capacity for different catalysts is also measured. First-principles calculation is used to study the adsorption and activation of CO2 on the ZnO surface. We envision that this work may afford an efficient approach to develop the semiconductor photocatalysts with superior activity via defects engineering.
关键词： Photoreduction,CO2,ZnO,Vacancy
更新于2025-09-10 09:29:36
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Photocatalytic Reduction of Bicarbonate to Formic Acid using Hierarchical ZnO Nanostructures
摘要： Zinc oxide (ZnO) is an earth abundant, non-toxic, and low-cost material that has been used widely for photocatalytic water splitting, gas sensing, and dye degradation. In this study, several ZnO structures were tested for the photochemical reduction of bicarbonate to formic acid, an intermediate to methanol, a high-octane-number fuel with higher energy density than compressed hydrogen. The different ZnO morphologies studied included micron- and nano-particulate ZnO, rods, wires, belts, and flowers. ZnO was also synthesized from the direct calcination of zinc acetate, which provided a cheap and large-scale synthesis method to produce ZnO. The photocatalytic efficiency of the synthesized ZnO was compared to commercial micron- and nano-particulate ZnO, and was proven to be just as efficient. ZnO flowers, possessing the largest surface area of 12.9 m2/g, were found to be the most efficient reaching an apparent quantum efficiency (AQE) of 10.04±0.09%, with a superior performance over commercial TiO2 (P25), a benchmark photocatalyst. This is the first study to compare different shapes and sizes of ZnO for bicarbonate reduction in an aqueous system with excellent photocatalytic performance.
关键词： solar fuels,ZnO nanostructures,zincite,bicarbonate photoreduction
更新于2025-09-10 09:29:36
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Highly efficient photocatalytic reduction of CO2 on surface-modified Ti-MCM-41 zeolite
摘要： Three dimensional microporous zeolites have attracted much attention in catalysis because of their large BET surface area and abundant pores. Herein, Ti-MCM-41 zeolites with different molar ratio of Si/Ti were synthesized, and the surface acidity and active sites were adjusted by the modification of basic-earth metal oxides, and noble metal nanoparticles. The photocatalytic activity and selectivity were evaluated by the reduction of CO2 to CH4 and CO. The results indicated that the efficiency and selectivity of CO2 photoreduction to CH4 of Ti-MCM-41 zeolites were 93 ppm·g-1·h-1 and 29% in the ratio Si/Ti=10 under keeping the zeolite structure, and which is much higher than that of P25 with the value of 24 ppm·g-1·h-1 and 23%. When the surface of Ti-MCM-41 zeolites was modified by different basic-earth metal oxides, the photo-reduction activity of CO2 to CH4 increased about 1.5 times with MgO modification, and the selectivity of CO2 to CH4 improved to 42%. Moreover, the photoactivity and selectivity enhanced to 8835 ppm·g-1·h-1 and 93% when the surface was further decorated by Pt nanoparticles, while the selectivity of CO2 to CO reached 94% when Pd was loaded. Our work reveal reasonably that adjusting the acidity and active site of the microporous zeolites is a highly efficient way to improve the photocatalytic efficiency of CO2 reduction.
关键词： Ti-MCM-41 zeolite,active sites,surface acidity,CO2 photoreduction
更新于2025-09-09 09:28:46
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Photoreduction of CO2 with a formate dehydrogenase driven by photosystem II using a semi-artificial Z-scheme architecture
摘要： Solar-driven coupling of water oxidation with CO2 reduction sustains life on our planet and is of high priority to contemporary research. Here, we report a photoelectrochemical tandem device, which performs photocatalytic CO2 reduction to formate. We employ a semi-artificial design, which wires a W-dependent formate dehydrogenase (FDH) cathode to a photoanode containing the photosynthetic water oxidation enzyme, photosystem II, via a synthetic dye with complementary light absorption. From a biological perspective, the system achieves a metabolically-inaccessible pathway of light-driven CO2 fixation to formate. From a synthetic point of view, it represents a proof-of-principle system utilizing precious-metal-free catalysts for selective CO2 to formate conversion using water as an electron donor. This hybrid platform demonstrates the translatability and versatility of coupling abiotic and biotic components to create challenging models for solar fuel and chemical synthesis.
关键词： Photoreduction,formate dehydrogenase,photosystem II,semi-artificial Z-scheme architecture,CO2
更新于2025-09-09 09:28:46
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Ferroelectric Polarization Promoted Bulk Charge Separation for Highly Efficient CO2 Photoreduction of SrBi4Ti4O15
摘要： Fast recombination of photogenerated charge carriers in bulk remains the major obstacle for photocatalysis nowadays. Developing ferroelectrics directly as photoactive semiconducting catalysts may be promising in view of the strong ferroelectric polarization that induces the anisotropic charge separation. Here, we report a ferroelectric layered perovskite SrBi4Ti4O15 as a robust photocatalyst for efficient CO2 reduction. In the absence of co-catalysts and sacrificial agents, the annealed SrBi4Ti4O15 nanosheets with the strongest ferroelectricity cast a prominent photocatalytic CO2 reduction activity for CH4 evolution with a rate of 19.8 μmol·h-1·g-1 in the gas-solid reaction system, achieving an apparent quantum yield (AQY) of 1.33% at 365 nm, outperforming most of the reported photocatalysts. The ferroelectric hysteresis loop, piezoresponse force microscopy (PFM) and ns-level time-resolved fluorescence spectra uncover that the outstanding CO2 photoreduction activity of SrBi4Ti4O15 mainly stems from the strong ferroelectric spontaneous polarization along [100] direction, which allows efficient bulk charge separation along opposite direction. DFT calculations also disclose that both electrons and holes show the smallest effective masses along a axis, verifying the high mobility of charge carriers facilitated by ferroelectric polarization. This study suggests that the traditionally semiconducting ferroelectric materials that have long been studied as ferro/piezoelectric ceramics now may be powerfully applied in the photocatalytic field to deal with the growing energy crisis.
关键词： CO2 photoreduction,ferroelectric perovskite,spontaneous polarization,SrBi4Ti4O15 nanosheets,piezoelectric-catalysis
更新于2025-09-09 09:28:46