Construction of NiCo-layered double hydroxide/Mn0.2Cd0.8S S-scheme heterojunction with electrostatic self-assembly for efficient photocatalytic hydrogen evolution.

NiCo-LDH with a layered structure was coupled to Mn 0.2 Cd 0.8 S through electrostatic self-assembly to construct tightly heterojunctioned photocatalysts. The bundles of stacked nanorods and the tightly packed sheets break the agglomeration of each other after electrostatic self-assembly, exposing more redox active sites. The introduction of NiCo-LDH further expands the light absorption of Mn 0.2 Cd 0.8 S towards the visible wavelength range, effectively improving the photoresponse performance. The charge density in NiCo-LDH increases after coupling and the transport direction of photogenerated carriers inside the photocatalyst follows the S-scheme heterojunction migration path. Photogenerated carriers are effectively separated, preserving the more redox-competent conduction band and valence band potentials. The reduction of charge transfer resistance and hydrogen evolution overpotential facilitated the hydrogen evolution reaction. Thus the optimised composite photocatalyst exhibits a significant improvement in hydrogen evolution performance (15.21 mmol·g−1h−1, approximately 28.17 times that of Mn 0.2 Cd 0.8 S) and maintained a good hydrogen evolution stability. [Display omitted] • Tight-contact NiCo-LDH/Mn 0.2 Cd 0.8 S photocatalyst was constructed through electrostatic self-assembly. • Charge transfer path following S-scheme heterojunction of NiCo-LDH/Mn 0.2 Cd 0.8 S is clarified. • Photocatalytic hydrogen evolution activity of NiCo-LDH/Mn 0.2 Cd 0.8 S reached 15.21 mmol·g−1·h−1. • 1D/2D interface enables fast migration of photogenerated carriers. [ABSTRACT FROM AUTHOR]