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

• Published in: International journal of hydrogen energy 2019-02, Vol.44 (8), p.4133-4142
• Main Authors: Cheng, Linhao, Xie, Sanmu, Zou, Yajun, Ma, Dandan, Sun, Diankun, Li, Zhihui, Wang, Zeyan, Shi, Jian-Wen
• Format: Article
• Language: English
• Subjects: Co-catalyst; g-C3N4; H2 evolution; Metal phosphide; Photocatalysis; Visible light
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2018.12.159

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 μmol 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. •A novel noble-metal-free FeCoP co-catalyst was developed for the first time.•The resultant FeCoP/g-C3N4 exhibits a hydrogen production rate of 347 μmol h−1 g−1.•The Schottky junction formed between FeCoP and g-C3N4 facilitated electrons' transfer.•The synergistic effects between Fe2P and Co2P can produce stronger driving force.