A Kinetically Matched Dual-Channel Catalyst Platform for Efficient Photocatalytic Oxidation: Insights From Combined Quasi in Situ Transient Photovoltage and fs-Transient Absorption Spectra

Abstract

The simultaneous accumulation of photo-holes and the specific activation of substrates present a significant challenge in photo-oxidation. Herein, we propose a dual-channel collaborative catalytic platform based on hollow TiO₂ microspheres, using Cu single-atom (SA) catalysts and a composite polymer chain, to create separating pathways for unidirectional photogenerated electron/hole extraction. Ferrocene-functionalized graphene quantum dots are incorporated within the polymer chain for driving benzylamine (BA) oxidation. Quasi in situ transient photovoltage and femtosecond transient absorption tests reveal that leveraging the ultrafast charge separation capability of Cu SAs (0.44 ps) not only accelerates hole transport kinetics but also induces requisite Lewis acidity for the adsorption and activation of BA. In an air atmosphere, the rate of imine production reaches 4.81 mmol g⁻¹ h⁻¹ (selectivity of 98%). This study demonstrates the rational design of an SA/polymer chain dual-driven catalytic platform for optimizing kinetics and precisely controlling photocatalytic transformations in organic chemistry.

Keywords

graphene quantum dot / hole transfer channel / photocatalytic benzylamine oxidation / single-atom catalyst / substrate activation

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