Noble-metal-free Fe2P-Co2P co-catalyst boosting visible-light-driven photocatalytic hydrogen production over graphitic carbon nitride: The synergistic effects between the metal phosphides

Photocatalytic hydrogen evolution from water splitting driven by visible light is a promising approach to solve energy crisis and environmental problems, and noble-metal-free co-catalysts for boosting the hydrogen evolution reaction are highly desired. Herein, we explore a novel noble-metal-free Fe2P-Co2P co-catalyst for the first time to boost the photocatalytic performance of graphitic carbon nitride (g-C3N4). The resultant Fe2P-Co2P/g-C3N4 with optimum ratio exhibits a hydrogen production rate of 347 mu mol h(-1) g(-1) in the absence of noble-metal co-catalyst, which is 87 times higher than that of pristine g-C3N4 under the same conditions. The significant enhancement in the photocatalytic performance of Fe2P-Co2P/g-C3N4 can be ascribed to the Schottky junction formed between Fe2P-Co2P and g-C3N4, which produces a strong driving force for the transfer of electrons from g-C3N4 to Fe2P-Co2P, promoting the separation and transfer of photogenerated electrons and holes. Furthermore, due to the synergistic effects between the two metal phosphides (Fe2P and Co2P), the Schottky junction in Fe2P-Co2P/g-C3N4 can produce stronger driving force than that in Fe2P/g-C3N4 and Co2P/g-C3N4, resulting in the fact that the hydrogen production rate over Fe2P-Co2P/g-C3N4 is much higher than that over Fe2P/g-C3N4 and Co2P/g-C3N4. This work may shed light on the careful design of co-catalyst by utilizing the synergistic effect of different components. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.