Metallic Co2C: A Promising Co-catalyst To Boost Photocatalytic Hydrogen Evolution of Colloidal Quantum Dots

Transition-metal carbide (TMC), because of its electronic conductivity, chemical stability, and physical properties, has aroused widespread interest in catalysis. Here, we have systematically studied the photocatalytic hydrogen (H2) evolution of metallic cobalt carbide (Co2C) by a combination of theoretical and experimental investigations. In terms of intrinsic proton reduction property of the Co2C (020) facet and facile interficial electron transfer, the assembled architecture of quantum dots (QDs)/Co2C can give a rate of ∼18 000 μmol g–1 h–1 (λ = 450 nm), using TMC as co-catalysts and an apparent quantum yield of ∼2.7% of photocatalytic H2 evolution, an ∼10-fold enhancement, compared with bare QDs under identical conditions. Our results indicate that Co2C with suitable morphology and facet exposure can work as a co-catalyst to achieve photocatalytic H2 evolution.