GdOCl-modified polymeric carbon nitride heterojunction for one-photon excitation efficiently driven photocatalytic hydrogen production

Abstract

Visible light driven photocatalytic hydrogen evolution using sacrificial agents is a promising route for solar to chemical energy conversion. However, achieving efficient charge separation and migration in heterogeneous semiconductor photocatalysts through a one-photon excitation process remains challenging. In this work, we report a one-photon excitation approach by integrating polymeric carbon nitride (PCN) with gadolinium oxychloride (GdOCl) by a molten salt method for photocatalytic hydrogen evolution over PCN/GdOCl photocatalysts. Notably, the optimized PCN/GdOCl-1.5 exhibits an impressive H₂ performance with a yield of 86.38 μmol h⁻¹, surpassing bare PCN by a factor of 4.7. Additionally, PCN/GdOCl-1.5 showcases enhanced photocatalytic H₂ production with an apparent quantum efficiency (AQE) of 6.17% under monochromatic light at 420 nm. The improved separation of photogenerated charge carriers and reduced recombination rates in PCN/GdOCl-1.5 were evidenced by photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). In addition, the photocatalyst displays outstanding stability and retains its photocatalytic performance over five successive reaction cycles, thereby emphasizing the potential of PCN/GdOCl-1.5 for efficient and sustainable hydrogen evolution. The enhanced H₂ evolution performance is attributed to visible light excitation of PCN, followed by GdOCl assisted interfacial charge regulation and built-in electric field (BIEF) driven charge carrier migration. This work provides insight into the design of PCN based heterojunction photocatalysts for sacrificial agent assisted photocatalytic hydrogen evolution.