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Clay Mineral-Derived Silica Nanosheets as a Sustainable Platform for Photochemical Synthesis of Supported Metal Catalysts

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posted on 2024-11-14, 13:04 authored by Zhaoli Yan, Yanmin Chen, Yongsheng Yu, Xi He, Peng Liu, Qiangshan Jing
Clay minerals and their derivatives are valued for their unique, low-dimensional nanostructures. It is imperative to explore the characteristics of nanoclay-based matrix materials for the green synthesis of functional composites. This study reveals the defect-induced semiconductor-like optical properties of kaolinite clay-derived silica nanosheets (SiNSs) and employs SiNSs as a sustainable support and photoinduced reducing agent for the photochemical synthesis of supported metal nanoparticles (NPs). Results show that SiNSs feature defects that show UV absorption ability, a band gap of 2.99 eV, and higher photogenerated carrier separation efficiency than kaolinite and fumed nanosilica. Consequently, the photoexcited electrons of SiNSs under UV irradiation efficiently reduce Ag/Cu-amine precursors to produce SiNS-supported Ag-only and AgCu-alloy NPs. Furthermore, the impact of UV intensity on the Ag/Cu ratio and composition of alloy NPs due to the metal–support interaction and alloying effect is clarified. The optimal AgCu/SiNS-5 composite consisting of Ag0.35Cu0.65 alloy NPs (∼12 nm) exhibits superior catalytic activity for p-nitrophenol reduction within 40 s with a turnover frequency of 4.36 min–1 owing to high adsorption and reactivity of the interfacial and alloying active sites, and multiple electron transport pathways enabled by the alloying effect of Ag0/Cu+/Cu0/(AgCu)0. This work indicates the great potential of clay-derived SiNS’s optical properties in photochemical synthesis of supported metal catalysts, emphasizing the key roles of metal–support interaction and alloying effect in synthesis and catalysis.

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