Ga alloying-induced electronic modulation of Pt synergized with COFs for boosting photocatalytic CO2 reduction

Abstract

Photocatalytic reduction of CO₂ to valuable chemicals offers a sustainable strategy to address energy and environmental challenges. However, achieving efficient CO₂ activation on metal cocatalysts remains hindered by the uncontrollable competing H₂ evolution. Here, we demonstrate a synergistic approach that combines d-band engineering of the metal cocatalyst and covalent organic framework (COF)-mediated microenvironment regulation to enhance photocatalytic CO₂ reduction. The construction of a Ga–Pt alloy on a COF scaffold (Ga–Pt@COF) downshifts the Pt d-band center through Ga incorporation. This electronic modulation weakens hydrogen adsorption and generates CO₂-philic Ga–Pt sites that promote CO₂ binding. Meanwhile, the COF acts as a functional matrix that not only channels photogenerated electrons to the Ga–Pt active sites but also enriches the local CO₂ concentration around them. The optimized Ga–Pt@COF system exhibits a remarkable syngas production rate of 5.3 mmol g⁻¹ h⁻¹ with a consistent 1 : 1 ratio, a performance that outperforms most reported Pt-based analogues. This work provides a high-performance photocatalyst for CO₂ conversion and a promising design strategy for enhancing CO₂ reduction through synergistic electronic and microenvironmental modulation.