Cu/TiO2 octahedral-shell photocatalysts derived from metal–organic framework@semiconductor hybrid structures

Abstract

The insertion of metal cocatalysts into semiconductor photocatalysts, which can promote electron–hole separation and provide additional reaction sites, is a popularly used approach to improve photocatalytic efficiency. In this article, we demonstrate a facile synthetic method for Cu/TiO₂ photocatalysts with hollow structures by templating on metal–organic frameworks (MOFs). The Cu₃(BTC)₂ MOF octahedral microcrystals enwrapped by TiO₂ shells serve as a Cu precursor for the in situ generation of Cu nanoparticles on the TiO₂ photocatalyst. This method offers the versatility to tailor the photocatalyst configurations (including compositions, crystal phases, cocatalyst sizes, etc.) by simply altering the treatment conditions on MOF cores (e.g., room-temperature etching, simultaneous etching and reduction, and high-temperature calcination reduction). Enabled by the varied configurations, the synthesized octahedral-shell photocatalysts exhibit remarkably different performances in charge separation and photocatalytic hydrogen production, allowing the identification of an optimal design for photocatalysis.