One-pot, solid-state loading of Zn into g-C3N4 for increasing the population of photoexcited electrons and the rate of photocatalytic hydrogen evolution

Abstract

In this research, we load g-C3N4 with Zn through a simple, one-pot solid-state route that results in appreciably improved photocatalytic activity for H2 evolution under visible light. X-ray photoelectron spectroscopy and synchrotron X-ray absorption near edge structure spectroscopy confirm that the Zn species are present in the +2 oxidation state, coordinated to O atoms in the form of nanoclusters. Following the Zn loading, the host g-C3N4 absorbs more light in the UV and visible regions, while its physical features are almost unaltered. In the absence of any co-catalysts, a H2 evolution rate as high as 26.3 μmol/g·h can be achieved by g-C3N4 loaded with 0.2 atomic% of Zn, more than 8 times higher than that of g-C3N4 (3 μmol/g·h). Our results then provide strong evidences that the photocatalytic activity of Zn-loaded g-C3N4 for H2 evolution is directly controlled by the population of photoexcited electrons.