CdS@Ni3S2 for efficient and stable photo-assisted electrochemical (P-EC) overall water splitting

CdS@Ni3S2 photoelectrode exhibits both excellent electron-to-hydrogen and photo-to-hydrogen conversion efficiency in an innovative P-EC overall water splitting process. [Display omitted] •CdS@Ni3S2 photoelectrode realized photo-assisted electrochemical overall water splitting.•The photo-assisted electrochemical and pure electrochemical water splitting were contrastively investigated.•The intrinsic functions of photocatalyst and electrocatalyst in CdS@Ni3S2 photoelectrode were revealed.•Both of electrical-to-hydrogen (ηETH) and solar-to-hydrogen (ηSTH) conversion efficiency were investigated. CdS-based photoanodes have attracted tremendous attention for photoelectrochemical (PEC) water splitting. Combining CdS with state-of-the-art transition-metal electrocatalyst is an advantages strategy to increase both the photoactivity and photostability of CdS. It is worth noting that in this study, with considering the original electrocatalytic (EC) water decomposition function of the electrocatalyst, we provide further understanding on how the photocatalyst affect the electrocatalyst. By using an advantageous photo-assisted electrochemical (P-EC) overall water splitting strategy, it is found that CdS@Ni3S2 core–shell nanoarrays is an efficient photoanode for synergistically photo-electrical catalytic hydrogen production. The intrinsic EC, PEC and P-EC properties of CdS photocatalyst and Ni3S2 electrocatalyst in CdS@Ni3S2 photoelectrode are comparably studied. In a six-hour long time period, the average P-EC water splitting H2 production rate of CdS@Ni3S2 is 178.1 μmol∙cm−2∙h−1, which reaches 123.3% times of its neat electrochemical (EC) water splitting (144.4 μmol∙cm−2∙h−1), corresponding to a 2.22% solar-to-hydrogen (STH) efficiency. This work provides an important research foundation for the development of high-efficiency photo-electrical catalytic system.