Bioinspired spike-like double yolk–shell structured TiO2@ZnIn2S4 for efficient photocatalytic CO2 reduction

Abstract

Photocatalytic carbon dioxide (CO₂) reduction (PCR) into syngas is one of the sustainable approaches for recycling CO₂ into value-added chemical feedstocks. However, the PCR efficiency is often limited by the insufficient light-harvesting and poor charge separation. Herein, we design a spike-like double yolk–shell structured TiO₂@ZnIn₂S₄ (D-Y-TiO₂@ZnIn₂S₄) photocatalyst with superior PCR efficiency. The unique design not only integrates advantages of increasing active sites, surface areas and light-harvesting capacity induced by the hierarchical morphology, but also facilitates photo-induced charge separation based on the heterojunction of TiO₂ and ZnIn₂S₄. Owing to the combination of structural and compositional merits, the optimized D-Y-TiO₂@ZnIn₂S₄ photocatalyst shows superior PCR performance (325.29 μmol CO per g; 227.18 μmol H₂ per g) under visible light. In addition, the ratio of CO/H₂ can be tuned from 0.03 to 1.43 by changing the sacrificial hole capture condition. This work provides a prospective way to obtain efficient PCR photocatalysts.