Ni–CdS composited with ZnO for improved surface reaction and charge efficiency for photocatalytic hydrogen production from formic acid

Formic acid (FA) is an ideal liquid organic hydrogen carrier (LOHC). It is of great significance in the construction and design of efficient and stable photocatalytic systems for H₂ generation from FA decomposition. Herein, enhanced photocatalytic H₂ production performance was achieved by compositing surface nickel modified cadmium sulfide (Ni-CdS) with zinc oxide. The research results indicate that the introduction of zinc oxide can not only promote the migration of photo-generated charge carriers, but also facilitate the adsorption of water molecules on the photocatalyst surface, thereby enhancing the production of hydroxyl radicals, which is a key species in the photocatalytic FA decomposition process for H₂ production. Without changing the photocatalytic FA decomposition reaction pathway, Ni-CdS@ZnO-<i>X</i> composite material exhibits excellent photocatalytic H₂ production activity and recycling stability. The H₂ production activity can reach 17 mmol g^-1 h^-1, which is about 2.3 times that of single Ni-CdS material and there is no significant decline in photocatalytic performance over five cycles. This study provides a new modification route for efficient and stable photocatalytic H₂ production from FA decomposition under mild conditions.