1T-phase MoS2 quantum dots as a superior co-catalyst to Pt decorated on carbon nitride nanorods for photocatalytic hydrogen evolution from water

Abstract

Molybdenum disulfide (MoS₂) has been confirmed to be a promising non-precious-metal co-catalyst for photocatalytic hydrogen (H₂) evolution; however, its low-density of active sites and poor electron transfer efficiency have essentially limited its photocatalytic properties. Here we report that 1T-MoS₂ quantum dots (QDs) can exceed the performance of noble metals like Pt as co-catalysts in assisting photocatalytic H₂ evolution upon forming a heterostructure with C₃N₄ nanorods (denoted as 1T-MoS₂@C₃N₄ NRs). The presence of 1T-MoS₂ QDs is found to improve light harvesting, enhance electronic conductivity as well as boost the density of active sites, resulting in an excellent light absorption range up to the near-infrared (NIR) region and a highly efficient spatial charge separation and transfer process. As a result, the optimized 1T-MoS₂@C₃N₄ NR composite (5.0 wt%) exhibits an extraordinary photocatalytic H₂ production rate of 565 μmol h⁻¹ g⁻¹ under simulated solar light irradiation, obviously higher than that of noble metal Pt loaded C₃N₄ NRs (318 μmol h⁻¹ g⁻¹). Moreover, the 1T-MoS₂@C₃N₄ NR composites exhibit good stability in the cyclic runs for photocatalytic H₂ production. This study indicates that the highly active MoS₂ as a co-catalyst is highly promising as a substitute for Pt for photocatalytic H₂ evolution.