Improved H-adsorption ability and conductivity of a Co-doped Mo2N cocatalyst for efficient photocatalytic H2 generation of g-C3N4. (9th December 2022)

• Record Type: Journal Article
• Authors: Lu, Zhongxi; He, Xudong; Jin, Cheng; Jiang, Haopeng; Yu, Xiaohui; Sun, Lijuan; Wang, Weikang; Wang, Lele; Liu, Qinqin
• Is Part Of: New journal of chemistry. Volume 47:Number 2(2023)
• Page Start: 772
• Page End: 782
• Publication Date: 2022-12-09
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d2nj05003j
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Cocatalysts are usually applied in the photocatalytic water splitting process to accelerate the kinetics of the hydrogen evolution reaction (HER). Abstract : Cocatalysts are usually applied in the photocatalytic water splitting process to accelerate the kinetics of the hydrogen evolution reaction (HER). Specifically, the transition metal nitride (Mo2 N) featuring a unique local surface plasmon resonance (LSPR) effect has exhibited great potential to function as a HER cocatalyst. However, the low metallicity of Mo2 N hampers its ability to improve charge separation. To address this issue, transition metal atom doping (Co and Cu) engineering was used to modulate the electronic structure of Mo2 N nanosheets to achieve a higher electrical conductivity and a lower hydrogen adsorption free energy (|Δ G H* |), thereby favoring the HER kinetics. Density functional theory (DFT) calculations and experimental results showed that Co-doping and Cu-doping mainly take place at Mo sites in the crystal structure of Mo2 N to form stable structures of Co doped Mo2 N (Co–Mo2 N) and Cu doped Mo2 N (Cu–Mo2 N). Compared with pristine Mo2 N, both Cu–Mo2 N and Co–Mo2 N demonstrated a much improved cocatalytic effect over g-C3 N4 in promoting charge separation, accelerating HER kinetics and enhancing light absorption. The Co–Mo2 N with the highest conductivity and lowest |Δ G H* | illustrated the best cocatalytic effect, and the H2 production performance (367.8 μmol g −1 h −1 ) of Co–Mo2 N/g-C3 N4 achieved was 10 and 5 times higher than those of Mo2 N/g-C3 N4 and Cu–Mo2 N/g-C3 N4 . This paper provides significant guidance in the design and development of efficient cocatalysts for the HER application.