Enhanced visible light-driven hydrogen evolution in non-precious metal Ni2P/CdIn2S4 S-type heterojunction via rapid interfacial charge transfer

Abstract

Strong light absorption capacity and effective separation of photogenerated charge are the keys to photocatalytic water decomposition, which is usually solved by constructing heterojunction methods. In this work, a novel n-n interwoven Ni2P/CdIn2S4 S-type heterojunction photocatalyst was prepared by hydrothermal method for efficient photocatalytic hydrogen evolution. After a series of characterization and performance tests, under simulated sunlight irradiation at 6 °C (λ > 420 nm), the hydrogen production of Ni2P/CdIn2S4 composite with the best performance can reach 6 mmol/g/h, which is not only 48 times that of pure CdIn2S4, but also 17.2 times that of the expensive metal Pt (CIS–1Pt). By changing the temperature, the hydrogen production of Ni2P/CdIn2S4 reached 8.7 mmol/g/h at 27.5 °C, while its AQY reached 7.7 % and 6.6 % at 420 nm and 475 nm, respectively. In addition, the possible photocatalytic mechanism was analyzed by band structure and XPS diagram, and it was confirmed that the internal electric field of the S-type heterojunction accelerated the photogenerated charge transition and enhanced the hydrogen evolution ability. This effectively compensated for the limitations of severe carrier recombination and low active sites in CdIn2S4 photocatalysts. Therefore, this work provides some help for the construction of non-precious metal S-type heterojunctions for photocatalytic hydrogen production.