Combination of polyoxotantalate and metal sulfide: A new-type noblemetal-free binary photocatalyst Na8Ta6O19/Cd-0.7 Zn0.3S for highly efficient visible-light-driven H-2 evolution

摘要

Polyoxometalates have been emerged in the field of photocatalytic hydrogen evolution reaction (HER) with attempt to get efficient, inexpensive, recyclable, and environmentally-benign photocatalysts. Here, it demonstrated that the combination of polyoxotantalates with metal sulfides can form none-noble-metal binary composite photocatalysts for efficient water splitting with visible-light. With the strategy, the first series of noble-metal-free composite photocatalysts based on the combination of hexatantalate Na8Ta6O19 and metal sulfide CdxZn(1-x)S have been prepared and used as a heterogeneous photocatalyst. The Na8Ta6O19/CdxZn(1-x)S exhibits efficient hydrogen production activity, even without any cocatalysts. The maximum H-2-evolution rate reaches 43.05 mmol h(-1) g(-1) (based on 10 mg catalyst) with the apparent quantum yield of 37% at 420 nm, which is the highest value ever reported so far for polyoxometalate-based photocatalysts to our knowledge. The achievement provides a new strategy to develop highly efficient and new-type photocatalysts for the sustainable utilization of solar energy by merging polyoxotantalate chemistry with photoredox catalysis.