Effects of various alcohol sacrificial agents on hydrogen evolution based on CoS2@SCN nanomaterials and its mechanism

Visible light induced photocatalysis converted solar energy to chemical energy in the form of hydrogen. g-C 3 N 4 modified by thermal oxidation etching, doped S, and nonprecious metal cocatalyst CoS 2 (CoS 2 @SCN) were used for photocatalytic hydrogen production. And then the charge transfer behavior and mechanism of various alcohol sacrificial agents on hydrogen evolution was analyzed by optical characterization, impedance analysis, Mott-Schottky, and photocurrent tests. The relationship between the structure and catalytic performance was also explored using characterization methods. The results showed that CoS 2 significantly improved the light absorption of g-C 3 N 4 , and carrier migration and separation. And when the sacrificial agent was triethanolamine, the nanocomposite CoS 2 @SCN exhibited best catalytic performance with the highest hydrogen activity of 223.6 μmol g −1 h −1 , the minimum volume in-phase charge transfer resistance with 55.19 Ω and the maximum photocurrent and photocurrent density with 5.5 μA cm −2 and 0.63 mA cm −2 . The more negatively charged surface of organic alcohols were, the easier they were to react with holes, thus enhanced charge transfer and hydrogen production efficiency. This report provides guidance for the selection of hydrogen producing sacrificial agents and preparation of highly charge-efficient catalysts. And it also provides a theoretical basis for hydrogen production from wastewater and environmental remediation. • CoS 2 @SCN exhibits high charge utilization and good catalytic performance. • The charge transfer mechanism in hydrogen evolution process of CN, SCN and CoS 2 @SCN were identified. • The effective charge in the presence of sacrificial agent increases and diffuses into the solution.