Photocatalytic Dehydrogenation of Formic Acid on CdS Nanorods through Ni and Co Redox Mediation under Mild Conditions

Abstract

Selective release of hydrogen from formic acid (FA) is deemed feasible to solve issues associated with the production and storage of hydrogen. Here, we present a new efficient photocatalytic system consisting of CdS nanorods (NRs), Ni, and Co to liberate hydrogen from FA. The optimized noble-metal-free catalytic system employs Ni/Co as a redox mediator to relay electrons and holes from CdS NRs to the Ni and Co, respectively, which also deters the oxidation of CdS NRs. As a result, a high hydrogen production activity of 32.6 mmol h^-1 g^-1 from the decomposition of FA was noted. Furthermore, the photocatalytic system exhibits sustained H₂ production rate for 12 h with sequential turnover numbers surpassing 4×10³ , 3×10³ , and 2×10³ for Co-Ni/CdS NRs, Ni/CdS NRs, and CoCl₂ /CdS NRs, respectively.

Keywords: CdS nanorods; formic acid dehydrogenation; hydrogen production; photocatalysis; redox mediation.