Well-designed glucose precursor carbon/g-C3N4 nanocomposite for enhanced visible light photocatalytic CO2 reduction activity

Fabrication of glucose precursor carbon-doped g-C3N4 nanocomposite (C/g-C3N4) for enhancing photocatalytic CO2 reduction into syngas (CO, CH4) has been investigated. The samples were successfully synthesized via a two-step thermal treatment and tested in a fixed bed reactor under visible light. The 0.2 % glucose precursor carbon-doped over g-C3N4 photocatalyst has demonstrated excellent activity in converting CO2 to CO and CH4 under visible light. The main product yield, CO of 898.9 μmol g-cat−1 was produced over 0.2 % C/g-C3N4, which is 4.6 folds the amount of CO obtained over the g-C3N4 (196.8 μmol g-cat−1). The XPS results confirmed the formation of a C-O-C bond between carbon and g-C3N4, resulting in a strong interaction between carbon and g-C3N4. Carbon-doped g-C3N4 possesses a narrow energy band and the ability to effectively absorb solar light, which enables efficient transportation of electrons generated by photon excitation. Possible reaction mechanisms for photoreduction of CO2 over carbon-doped g-C3N4 photocatalyst were proposed in order to understand the movement of electrons and holes. This work provides a simple method for designing highly efficient carbon-based photocatalysts for potential application in photocatalytic CO2 reduction using solar energy.