0D/2D NiS/CdS nanocomposite heterojunction photocatalyst with enhanced photocatalytic H2 evolution activity

Highlights: • 0D/2D NiS/CdS nanocomposite heterojunctions are constructed. • Photocatalytic H₂-production rate is greatly enhanced. • An internal-field-induced charge transfer path like S-scheme mechanism is proposed. • KPFM technique is introduced. Photocatalytic H₂ production under visible light irradiation is of paramount importance in energy transformation and ecotope conservation. Herein, a heterojunction composed of zero-dimension (0D) nickel sulfide (NiS) nanoparticle and cadmium sulfide (CdS) flower is tactfully constructed. Particularly, the obtained nanocomposite, whose molar ratio of NiS is 25%, yields a remarkable photocatalytic performance. Its H₂-production rate reaches 18.1 mmol h⁻¹ g⁻¹, which is approximately 69.6 folds higher than that of pristine CdS. The excellent photocatalytic H₂ evolution reaction (HER) activity can be mainly attributed to the intimate contact and efficient separation of photoinduced carriers across the interface. This work also presents a new direction in understanding the performance improvement in composite photocatalysts.