CO2 mass transfer optimization for enhanced photocatalytic CO2 reduction via a surface CO32− layer reconstruction

The conversion of CO 2 into value-added chemicals using solar energy represents an ideal pathway to address the energy and environmental crises. However, the application of photocatalytic CO 2 reduction is still being hindered by the low CO 2 mass transfer and rapid charge carriers’ recombination. In this study, a Ga 2 O 3 /La 2 O 2 CO 3 composite heterojunction (GaO/LaOCO) with a surface rich in La(OH) 3 was constructed, successfully achieving both enhanced CO 2 adsorption and charge-separation efficiency. The composite undergoes a surface reconstruction of La(OH) 3 to La 2 (CO 3 ) 3 , resulting in a surface CO 3 2− layer that is conducive to CO 2 chemical adsorption and activation. In addition, band structure analysis confirms the formation of an energy-level alignment favorable for directional charge transfer. Under simulated sunlight, the prepared composite exhibits optimal photocatalytic CO 2 reduction activity without sacrificial agents and photosensitizers, achieving a CO production rate of 15.33 μmol g −1 over 5 h, along with good cycling stability. This enhanced activity originates from the synergy between surface La(OH) 3 for CO 2 enrichment/activation and Ga 2 O 3 for efficient electron transport. This work provides a strategy for enhancing photocatalytic CO 2 reduction performance by tailoring catalyst surface properties and interfacial structures.