Establishment of synergetic semiconductor (CdS)-to-heteroatom (C) electron transfer mechanism for alkaline water-to-hydrogen conversion

Solar-to-hydrogen (STH) conversion can synchronously implement the utilization of renewable energy and production of clean value-added fuel. However, the existing challenges for actual application of light-driven hydrogen production are the limited STH conversion efficiency, complex catalyst structure and high cost. Herein, the glucose here served as the precursor of carbon (C)-heteroatom was doped into the cadmium sulfide (CdS) body structure to promote its carriers separation and establish the interaction between C-heteroatoms and CdS via a one-step hydrothermal method. The semiconductor-to-heteroatom electron transfer significantly accelerated the migration of photoinduced electrons to catalyst surface, resulting highly increased light-to-hydrogen conversion efficiency. Up to 5.7 times HER rate of bare CdS was achieved by the optimized C0.2-CdS nanocatalyst in alkaline condition (pH = 14) at the absence of Pt cocatalyst, and about 21.78% of apparent quantum efficiency (AQE) was reached at 500 nm of light irradiation, which remarkably outperformed the performances reported in literatures. More importantly, the C-heteroatom doping significantly enhanced the photocatalytic stability of CdS. The first-principle calculations revealed that C-heteroatom doping dramatically reduced the activation energy (Ea) of H2O-to-H* conversion and barrier of H*-to-H2 conversion on CdS, which provided the theoretical evidence for the improved HER photoactivity. This study proposes a simple and eco-friendly procedure to improve the performance of CdS photocatalyst in an inexpensive mode.