The enhancement of CdS photocatalytic activity for water splitting via anti-photocorrosion by coating Ni2P shell and removing nascent formed oxygen with artificial gill

- The core-shell structured Ni2P@CdS was synthesized for overall water splitting.
- The Ni2P shell over CdS surface could inhibit CdS photocorrosion in water splitting.
- Artificial gill can remove nascent formed O2 from water and prevent the oxygen leading photocorrosion.
- The activity and stability of 10Ni2P@CdS is superior to that of typical Pt@CdS catalyst.
- The 10Ni2P@CdS catalyst could be a promising candidate to replace precious-metal catalysts of the HER.

CdS photocorrosion seriously impeded its application in photocatalysis, especially for water splitting. Here we report new strategies to improve CdS photocorrosion resistance properties significantly by coating Ni2P shell and assembling an artificial gill to remove newly formed O2 from water. Ni2P@CdS catalyst can achieve the over-all water splitting under visible light irradiation without addition of any sacrifice reagent and noble metal loading. Compared with CdS itself, the 10Ni2P@CdS photocatalyst exhibits excellent photocatalytic activity for hydrogen evolution (251.4 μmol of H2 in 180 min) with a high AQE (3.89% at 430 nm). This catalyst also presents high photocurrent, low overpotential (−0.32 V vs SCE), and long fluorescence lifetime (16.27 ns) of excited charges. Cd2+ ions concentration measured by ICP and long term stability results verified the anti-photocorrosion role of Ni2P shell on CdS during water splitting reaction. The activity and stability of 10Ni2P@CdS is even superior to typical 1Pt@CdS catalyst. Our results confirm CdS can be an active catalyst for photocatalytic hydrogen generation from water under visible irradiation if its stability is enhanced by protection of anti-photocorrosion over-coating shell and removing the nascent formed oxygen from water.

In this paper, we develop core-shell structured Ni2P@CdS photocatalyst by solvothermal method for high efficient HER under visible light irradiation without sacrifice reagent and noble metal loading. With help of artificial gill removing newly formed O2 from water, the oxygen leading photocorrosion was prevent and the hydrogen and oxygen reverse recombination back to water was inhibited. Compared with CdS itself, Ni2P@CdS core-shell photocatalyst exhibits better photocatalytic activity for water splitting. More importantly, Ni2P co-catalyst is a promising substitute for replacement of noble-metals in photocatalytic HER.257