Symmetry-breaking synthesis of Janus Au/CeO2 nanostructures for visible-light nitrogen photofixation

Abstract

Precise manipulation of the reactive site spatial distribution in plasmonic metal/semiconductor photocatalysts is crucial to their photocatalytic performance, but the construction of Janus nanostructures through symmetry-breaking synthesis remains a significant challenge. Here we demonstrate a synthetic strategy for the selective growth of a CeO₂ semi-shell on Au nanospheres (NSs) to fabricate Janus Au NS/CeO₂ nanostructures with the assistance of a SiO₂ hard template and autoredox reaction between Ag⁺ ions and a ceria precursor. The obtained Janus nanostructures possess a spatially separated architecture and exhibit excellent photocatalytic performance toward N₂ photofixation under visible-light illumination. In this scenario, N₂ molecules are reduced by hot electrons on the CeO₂ semi-shell, while hole scavengers are consumed by hot holes on the exposed Au NS surface, greatly promoting the charge carrier separation. Moreover, the exposed Au NS surface in the Janus structures offers an additional opportunity for the fabrication of ternary Janus noble metal/Au NS/CeO₂ nanostructures. This work highlights the genuine superiority of the spatially separated nanoarchitectures in the photocatalytic reaction, offering instructive guidance for the design and construction of novel plasmonic photocatalysts.