Synthesis of hierarchical tandem double Z-scheme heterojunctions for robust photocatalytic H2 generation

Abstract

The design of advanced structures for semiconductor photocatalysts is one of the most tremendous approaches to stimulate their conversion performance from solar energy to chemical energy. Nonetheless, it is challenging to harvest the full solar spectrum in semiconductor photocatalysts for excessive activity. Herein, a hierarchical CuCo2O4/graphdiyne/CuO nanocages (CCOGC NCs) tandem heterojunction was once effectively synthesized by means of liquid–liquid interface method for the first time and a facile calcination method. The graphdiyne nanosheets (GDY NSs) not only function as a cost-effective cocatalyst but also act as a bridge to connect two light-harvesting semiconductors into a tandem heterojunction where the CuCo2O4 (CCO) NCs and CuO Quantum dots (QDs) absorb visible light on both sides efficiently, coupling with the GDY NSs into a double Z-scheme photocatalyst system. Benefiting from the novel hierarchical tandem nanocages structure, the optimized CCOGC NCs photocatalyst manifests high activity under visible light irradiation with the hydrogen (H2) generation rate of 9617 µmol h−1 g−1, which is much enhanced compared with those of the CCO NCs and CCO/GDY NCs (CCOG NCs), as well CCO/CuO (CCOC NCs).