Quantum confinement-induced rapid electron transfer augmenting strong electron coupling in 0D/2D WP quantum dots/MnCdS-Vs Schottky Junction for robust photocatalytic hydrogen production

Abstract

The effective strategy to improve the hydrogen evolution activity in photocatalytic processes is the inhibition of electron-hole pair recombination in semiconductors through induced electron transfer. In this work, a 0D/2D WP QDs/MnCdS-Vs Schottky junction (WMCS) was constructed by immobilized WP quantum dots (WP QDs) on S-vacancy rich MnCdS (MnCdS-Vs) nanosheets for efficient photocatalytic hydrogen evolution. WP QDs with average size of 4.78 nm can be fully in contact with MnCdS-Vs to shorten the electron transmission distance. The quantum confinement effect of WP QDs makes the transport of electrons more efficient between the interface of the 0D/2D WP QDs/MnCdS-Vs Schottky junction. This efficient electron transport helps to reduce the recombination of photogenerated carriers and augmenting strong electron coupling in 0D/2D WP quantum dots/MnCdS-Vs Schottky junction, thereby improving the efficiency of photocatalytic hydrogen production. DFT calculation and in-situ XPS proved that the photogenerated electrons in MnCdS-Vs transition to metallic WP QDs through the Schott barrier, WP QDs participates in hydrogen evolution as an electron aggregation site. Consequently, WMCS-15 exhibits superior hydrogen evolution performance at 11467.73 μmol g⁻¹ h⁻¹, which is 5.83 times higher than that of MnCdS-Vs. This work provides important insights into rapid electron transfer induced by quantum confinement-induced and enhanced electron coupling to achieve efficient photocatalytic hydrogen production.