Composite plasmonic gold/layered double hydroxides and derived mixed oxides as novel photocatalysts for hydrogen generation under solar irradiation

Abstract

We report here the self-assembly of Au nanoparticles/mesoporous matrices of layered double hydroxides (Au/ZnAlLDH and Au/ZnCeAlLDH) and the derived mixed oxides as novel plasmonic photocatalysts for H₂ production from water–methanol mixtures (80 : 20) by using solar irradiation, at room temperature. The fabrication of the Au/LDH composite is based on the formation of Au nanoparticles on the surface of the anionic clay during the manifestation of the clay structural “memory effect” in the aqueous solution of AuCl₃. All the catalysts exhibit strong light absorption at around 550 nm due to surface plasmon resonance (SPR) of nanosized gold. We found that not only the size-dependent characteristics of Au nanoparticles (e.g. D_Au, S_Au) but also the composition of the anionic clays are important parameters for establishing the effectiveness of catalysts for H₂ production by using solar light. The presence of cerium in the LDH layers leads to a larger population of positive Au (⁺ or ³⁺) on the catalyst surface and enhances the photocatalytic performances. These results open new opportunities for progress in the development of plasmonic nanoarchitectonics for solar-light driven photocatalysts for clean H₂ production.