posted on 2024-11-14, 13:04authored byZhaoli 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.