An insight into the trifunctional roles of Cu2(OH)2CO3 cocatalyst in boosting the photocatalytic H2 evolution activity over Zn0.5Cd0.5S nanoparticles.

The construction of efficient semiconductor/cocatalyst heterojunction is a promising strategy to promote the photocatalytic H 2 -production efficiency from water reduction. Herein, a novel Cu 2 (OH) 2 CO 3 /Zn 0.5 Cd 0.5 S heterojunction composite with superior photocatalytic H 2 -generation activity and stability was prepared via a facile in situ synthetic route, in which Cu 2 (OH) 2 CO 3 served as cocatalyst stimulating the photocatalytic H 2 -evolution performance of Zn 0.5 Cd 0.5 S. The Cu 2 (OH) 2 CO 3 /Zn 0.5 Cd 0.5 S heterojunction photocatalyst containing 5 wt% of Cu 2 (OH) 2 CO 3 exhibited a prominent H 2 -evolution efficiency of 275.7 μmol h−1, which is superior to the noble metal Pt-modified Zn 0.5 Cd 0.5 S photocatalyst (237.3 μmol h−1) and much higher than bare Zn 0.5 Cd 0.5 S (90.8 μmol h−1). The active Cu+/Cu0 species generated during the photoreaction process is responsible for the prominent H 2 -production activity of the heterojunction photocatalyst, which plays triple roles in enhancing the photoactivity of Zn 0.5 Cd 0.5 S via accelerating the charge separation, decreasing the overpotential of H 2 -generation and improving the reduction ability of photoinduced electrons. Moreover, the formed Cu+/Cu0 species during photoreaction can be readily oxidized back to Cu 2 (OH) 2 CO 3 upon exposure to air, thus restores the photoactivity and therefore enables good reusability of the Cu 2 (OH) 2 CO 3 /Zn 0.5 Cd 0.5 S heterojunction photocatalysts. This work provides a new insight into the fabrication of Cu 2 (OH) 2 CO 3 -assisted heterojunction photocatalysts with the highly stable and efficient performances for solar-to-chemical energy conversion. Unlabelled Image • A novel binary Cu 2 (OH) 2 CO 3 /Zn 0.5 Cd 0.5 S composite was successfully synthesized. • The trifunctional roles of Cu 2 (OH) 2 CO 3 cocatalyst were discussed. • Mechanism of the enhanced photocatalytic activity was illuminated. [ABSTRACT FROM AUTHOR]