Boosting visible-light hydrogen evolution on CdS hollow nanospheres with CoN as cocatalyst

Abstract

The photocatalytic water splitting to produce hydrogen is of great significance to solve the energy crisis, so the development and research of the visible-light-driven energy conversion have the priority in the progress of photocatalytic technology. Herein, we synthesized CdS with hollow sphere (CdS-HS) structure and combined it with CoN to form CoN/CdS-HS photocatalytic system. The particular hollow sphere structure and cocatalyst CoN in the CoN/CdS-HS system increase the utilization of visible light and promote the separation and transfer of photo-generated carriers for photocatalysts, which greatly improves photocatalytic performance of materials. The time‐resolved photoluminescence spectra shows that the carrier lifetime of 15%CoN/CdS-HS is 7.52 ns, which is much larger than that of CdS (4.26 ns). In addition, the hydrogen output of the optimized 15%CoN/CdS-HS is 4.57 times superior to that of pristine CdS-HS under the same conditions. The photocatalytic hydrogen evolution rate of 15%CoN/CdS-HS reaches 58.80 mmol/g.h under visible light with an apparent quantum efficiency (AQE) of 23.53% at 405 nm monochromatic light. After 25 h of photocatalytic reaction, the 15%CoN/CdS-HS can still maintain excellent overall stability. This work provides an idea for the design and development of efficient visible-light-driven photocatalysts in the future.