Ga Alloying-induced Electronic Modulation of Pt Synergized with COFs for Boosting Photocatalytic CO2 Reduction

Abstract

Photocatalytic reduction of CO2 to 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 generatesCO 2 -philic Ga-Pt sites that promote CO 2 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 CO 2 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.