Unveiling the charge transfer dynamics regulated by bonding evolution in single-atom Pt/C3N5 for boosting hydrogen evolution

Abstract

Single-atom catalysts offer a representative platform for heterogeneous catalysis, owing to their maximum atom utilization efficiency and enhanced catalytic performance can be achieved by tuning the local atomic configuration. However, there are rare reports on the charge transfer process and its influence on local atomic configuration during the photocatalytic process. Herein, we for the first time observe the charge migration and bond evolution of a single-atom Pt/C3N5 catalysts during the water splitting process by combining synchronous-illumination X-ray photoelectron spectroscopy (SI-XPS) with synchronous-illumination diffuse reflectance Fourier transform infrared spectroscopy (SI-DRIFTS). The results clearly reveal that the dynamic evolution of N-Ptδ+ (0 <δ < 2) bond not only provides a real transport channel for the rapid transferring of photo-induced electrons but also suppresses the reverse reaction of forming water from H2 and O2. Based on the above unique structure characterizations, single-atom Pt/C3N5 catalysts exhibit significantly enhanced hydrogen evolution activity (18.2 mmol·g-1·h-1) under visible light in comparison with metallic Pt-C3N5 (3.6 mmol·g-1·h-1).