Cooperation of congenital and acquisitus sulfur vacancy for excellent photocatalytic hydrogen peroxide evolution of CdS nanorods from air

Abstract

Photocatalysis over semiconductors for producing hydrogen peroxide (H2O2) due to its renewable and sufficient sunlight as driving force has attracted more attention. However, the H2O2 evolution performance that is severely dependent on surface structure of photocatalysts is still inferior. Here we design sulfur vacancies (Sv)-rich CdS nanorods (CdS NRs), and disclose that the congenital Sv and acquisitus Sv in-situ created in the reaction process co-contribute to the efficient photocatalytic H2O2 production. The CdS NRs with abundant congenital Sv exhibit higher carrier separation efficiency and remarkably stronger O2 adsorption ability. Importantly, we discover that the Sv concentration in all the CdS serial samples increases after the H2O2 evolution reaction compared with that before photocatalytic reaction, and the increase level of acquisitus Sv concentration inversely correlates with congenital Sv concentration. Theoretical calculations confirm that the O2 adsorption energy on the surface of CdS NRs with Sv (−0.723 eV) is much lower than that of defect-free CdS (1.293 eV). Optimized by the two types of Sv, CdS NRs-24 h delivers a superior photocatalytic H2O2 production rate of 2974.7 μmol g1h−1 under visible light, far exceeding the previously reported sulfide photocatalysts. This work is anticipated to offer new perspectives into designing and understanding of sulfides for photocatalytic H2O2 evolution.