Efficient photocatalytic hydrogen production from formic acid on inexpensive and stable phosphide/Zn3In2S6 composite photocatalysts under mild conditions. (13th August 2019)

• Record Type: Journal Article
• Authors: Duan, Shixiang; Zhang, Sujuan; Chang, Susheng; Meng, Sugang; Fan, You; Zheng, Xiuzhen; Chen, Shifu
• Is Part Of: International journal of hydrogen energy. Volume 44:Number 39(2019)
• Page Start: 21803
• Page End: 21820
• Publication Date: 2019-08-13
• Subjects: Hydrogen production -- Formic acid -- Photocatalysis -- Zn3In2S6 -- Ni2P -- MoP; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.06.179
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Developing an efficient, stable and low-cost photocatalytic hydrogen production from formic acid is a daunting challenge and has attracted the intense interest of many of researchers. In this paper, we report the synthesis of novel composite photocatalysts (Ni2 P/Zn3 In2 S6 (ZIS6) and MoP/ZIS6) and their catalytic performance for H2 production reaction from formic acid under visible light irradiation, in which Ni2 P and MoP were used as cocatalysts to enhance hydrogen generation activity of ZIS6. The photocatalytic hydrogen production rates of the optimized 1.5 wt% Ni2 P/ZIS6 (45.73 μmol·h −1 ) and 0.25 wt% MoP/ZIS6 (92.69 μmol·h −1 ) were 3.5 times and 7.2 times higher than that of the pure ZIS6 (12.88 μmol·h −1 ), respectively. The apparent quantum efficiency at wavelength λ = 400 ± 10 nm for the two photocatalysts was about 1.8% and 6.4%, respectively. Significantly, it was found that the remarkable improvement of hydrogen production performance is attributed to the introduction of the phosphide cocatalysts, which can serve as a charge separation center and an active site for photocatalytic hydrogen production from the decomposition of formic acid. The reaction mechanism of photocatalytic hydrogen production from formic acid was also proposed. Graphical abstract: Therein, the VB electrons are migrated to the CB of the ZIS6 and further transferred to Ni2 P or MoP with lower Fermi energy, leaving the holes in the VB and realizing the efficient separation of photogenerated carriers. Subsequently, two reactions will occur simultaneously on the surface of the composite photocatalysts. The photogenerated holes on the VB of ZIS6 lead to the direct dehydrogenation of COOH − to produce CO2, the H + dissociated from formic acid is reduced to H2 by the photogenerated electron derived from Ni2 P or MoP cocatalyst acting as a charge enrichment and an active center.Image 1 Highlights: The photocatalysts (Ni2 P/Zn3 In2 S6 (ZIS6) and MoP/ZIS6) were synthesized. The photocatalysts exhibit excellent activity for hydrogen production from formic acid. The reaction mechanism of photocatalytic hydrogen production was proposed.