Modulated Schottky barrier of CdS-molybdenum carbide by NiCo-LDH for promoting photocatalytic H2 production

For the photocatalytic system modified with transitional metals, an appropriate Schottky junction height is of crucial significance for efficiently promoting the transfer of photogenerated electrons and thus inhibiting the recombination of charge carriers. Hereinto, a nickel-cobalt bimetallic layered hydroxide (NiCo-LDH) lamina as transition layer was inserted between CdS and nitrogen-doped carbon-supported molybdenum carbide (MoC/NC) via a continuous two-step hydrothermal method, constructing a sandwich-structured MoC@LDH@CdS ternary composite photocatalyst. Thanks to such a meticulously designed nanoarchitecture of the as-obtained catalyst, the dual heterogeneous interface phases, CdS/NiCo-LDH and NiCo-LDH/MoC, are constructed on account of the crucial bridging role by NiCo-LDH. Therefore, not only a cascaded electron transfer channel is opened up following the path “CdS→NiCo-LDH→MoC”, but also the Schottky barrier of CdS/MoC is optimized, thus boosting the photo-electron transfer and suppressing the recombination of carriers. As a result, MoC@NiCo-LDH@CdS exhibits importantly promoted photocatalytic H 2 evolution performance, with a high rate of 44.77 mmol g −1 h −1 , which is a 13.3-fold and 1.39-fold over pure CdS and MoC@CdS, respectively. Moreover, the apparent quantum yield (AQY) reaches 3.01% at 420 nm. In addition, the photocatalytic durability of MoC@LDH@CdS is also greatly improved compared with the pristine CdS.