Rational design of H2 production sites for achieving photoconversion of CO2 with H2O into widely adjustable syngas and highly effective H2 evolution

Abstract

The photoconversion of CO₂ with H₂O into widely tunable syngas (CO and H₂) or pure H₂ production is regarded as a promising strategy to mitigate escalating energy shortages and climate change. Herein, anchoring the H₂ production sites onto the surface of CdIn₂S₄ (CIS) with a nanoscale hollow sphere allows for the photoconversion of CO₂ into syngas and water splitting to H₂. The CO/H₂ ratio can be realized in a remarkably wide range from 1:0.38 to 1:3.76. The optimized CIS/Co-PBA/NaY-5 hybrid exhibits superior photocatalytic syngas evolution up to 1458.48 μmol·g⁻¹·h⁻¹ (H₂/CO, 1152.29/306.19 μmol·g⁻¹·h⁻¹), and the H₂ evolution rate increases by 431.70% compared with CIS. The CIS/Co-PBA/NaY-5 hybrid exhibited not only superior H₂ evolution but also recyclability. The experimental, energy-dispersive X-ray spectroscopy, and electron spin resonance results indicate that the Co sites serve as H₂ production sites and promote the H₂ evolution reaction. In addition, the construction of a p-n heterojunction with a special micromorphology is beneficial for the separation/transfer of carriers.