Ultrathin Two-Dimensional ZnIn 2 S 4 /Ni x -B Heterostructure for High-Performance Photocatalytic Fine Chemical Synthesis and H 2 Generation.

Photocatalytic H 2 evolution coupled with organic transformation provides a new avenue to cooperatively produce clean fuels and fine chemicals, enabling a more efficient conversion of solar energy. Here, a novel two-dimensional (2D) heterostructure of ultrathin ZnIn 2 S 4 nanosheets decorated with amorphous nickel boride (Ni x -B) is prepared for simultaneous photocatalytic anaerobic H 2 generation and aromatic aldehydes production. This ZnIn 2 S 4 /Ni x -B catalyst elaborately combines the ultrathin structure advantage of the ZnIn 2 S 4 semiconductor and the cocatalytic function of Ni x -B. A high H 2 production rate of 8.9 mmol h -1 g -1 is delivered over the optimal ZnIn 2 S 4 /Ni x -B with a stoichiometric production of benzaldehyde, which is about 22 times higher than ZnIn 2 S 4 . Especially, the H 2 evolution rate is much higher than the value (2.8 mmol h -1 g -1 ) of the traditional photocatalytic half reaction of H 2 production with triethanolamine as a sacrificial agent. The apparent quantum yield reaches 24% at 420 nm, representing an advanced photocatalyst system. Moreover, compared with traditional sulfide, hydroxide, and even noble metal modified ZnIn 2 S 4 /M counterparts (M = NiS, Ni(OH) 2 , Pt), the ZnIn 2 S 4 /Ni x -B also maintains markedly higher photocatalytic activity, showing a highly efficient and economical advantage of the Ni x -B cocatalyst. This work sheds light on the exploration of 2D ultrathin semiconductors decorated with novel transition metal boride cocatalyst for efficient photocatalytic organic transformation integrated with solar fuel production.