Synthesis, characterization, and photocatalytic properties of Au nanoparticle-anchored TiO2 and CaCO3 core–shell composite particles

IF 2 4区 材料科学 Q3 MATERIALS SCIENCE, COATINGS & FILMS
Akihiro Kohno , Sana Ito , Kenta Kato , Hironobu Minowa , Atsushi Aratake , Yasuko Yamada Maruo
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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.
金纳米粒子锚定TiO2和CaCO3核壳复合粒子的合成、表征及其光催化性能
二氧化钛基光催化剂已经引起了相当大的关注,但对其光还原机制的深入了解对于改进材料的设计和应用至关重要。本研究以四异丙醇钛为原料,采用溶胶-凝胶法在CaCO3表面涂覆TiO2,合成了核壳复合材料。金纳米颗粒(AuNPs)随后被固定在复合材料表面。该CaCO3@TiO2复合材料采用碳化法在TiO2上沉淀CaCO3,其中CO2通过含有TiO2的饱和Ca(OH)2水溶液。以HAuCl4·4H2O为前驱体,通过沉淀将AuNPs固定在核壳粒子表面。对合成的光催化剂进行了各种物理化学表征。测定了光催化产生的CH4和CO的量。与AuNP/TiO2@CaCO3相比,AuNP/CaCO3@TiO2通过减少CO2产生的CH4多17倍,CO多1.4倍。所得结果表明,AuNP/CaCO3@TiO2中产生CH4的多电子还原发生在CaCO3附近,CaCO3是具有CO2吸附能力的绝缘体。此外,使用AuNP/CaCO3@TiO2制备的CH4的产生量比使用与AuNP/CaCO3@TiO2相同比例的物理混合TiO2和CaCO3制备的催化剂的产生量高1.1倍;物理混合光催化剂和沉淀光催化剂的化学结构的不同是其光催化效率差异的原因。本研究对现有的二氧化钛基材料光催化还原反应机理进行了进一步的研究。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Thin Solid Films
Thin Solid Films 工程技术-材料科学:膜
CiteScore
4.00
自引率
4.80%
发文量
381
审稿时长
7.5 months
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.
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