Akihiro Kohno , Sana Ito , Kenta Kato , Hironobu Minowa , Atsushi Aratake , Yasuko Yamada Maruo
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引用次数: 0
Abstract
TiO2-based photocatalysts have garnered considerable attention, yet a deeper understanding of their photoreduction mechanism is essential for improved material design and application. In this study, core–shell composites were synthesised by coating CaCO3, with TiO2 via a sol-gel method using titanium tetraisopropoxide. Gold nanoparticles (AuNPs) were subsequently anchored onto the composite surface. The CaCO3@TiO2 composite was prepared by precipitating CaCO3 on TiO2 using a carbonation method in which CO2 was passed through a saturated aqueous solution of Ca(OH)2 containing TiO2. The AuNPs were anchored to the surfaces of the core–shell particles via precipitation using HAuCl4 · 4H2O as the precursor. Various physicochemical characterizations were performed on the synthesised photocatalysts. The photocatalytically produced amounts of CH4 and CO were evaluated. As compared to AuNP/TiO2@CaCO3, AuNP/CaCO3@TiO2 produced 17 times more CH4 and 1.4 times more CO via CO2 reduction. The obtained results suggest that multi-electron reduction in AuNP/CaCO3@TiO2 to produce CH4 occurs near CaCO3, which is an insulator with CO2 adsorption ability. Furthermore, the amount of CH4 produced using AuNP/CaCO3@TiO2 was 1.1 times higher than that produced by a reported catalyst, which was prepared by physically mixing TiO2 and CaCO3 in the same ratio as that in AuNP/CaCO3@TiO2; the dissimilarity in the chemical structures of the physically mixed and precipitated photocatalysts was held responsible for the observed differences in their photocatalytic efficiencies. This study advances the existing knowledge about the mechanism of photocatalytic reduction reactions using TiO2-based materials.
期刊介绍:
Thin Solid Films is an international journal which serves scientists and engineers working in the fields of thin-film synthesis, characterization, and applications. The field of thin films, which can be defined as the confluence of materials science, surface science, and applied physics, has become an identifiable unified discipline of scientific endeavor.