Interfacial bonding of hydroxyl-modified g-C3N4 and Bi2O2CO3 toward boosted CO2 photoreduction: Insights into the key role of OH groups.

[Display omitted] • Novel interface-bonded OH-CN/BOC heterojunctions were fabricated by a simple mixing route. • The chemical bonding and its role on inducing stable OVs are elucidated by DFT calculation. • OH-CN/BOC exhibits enhanced CO yield that is 91.8 and 18.2 times of BOC and CN, respectively. • OH groups play a key and multiple roles in improving the photoreduction activity of OH-CN/BOC. The development of heterogeneous photocatalysts with superior photogenerated charge separation and CO 2 activation is a key challenge for artificial photosynthesis. Herein, novel hydroxyl-modified g-C 3 N 4 /flower-like Bi 2 O 2 CO 3 composites (OH-CN/BOC) with covalently bonded heterointerfaces were fabricated through a direct mechanical mixing approach. The bonded samples exhibited remarkable CO 2 photoreduction activity under visible light. The CO production rate of the optimized sample was 91.8, 18.2, 8.6, and 6.1 times greater than those of BOC, CN, OH-CN, and CN/BOC, respectively, reaching 26.69 μmol g-1h−1; and it remained stable after four cycles. The experimental and DFT studies reveal that the introduction of OH groups on CN leads to the chemical bonding of CN and BOC, induces stable surface oxygen vacancies (OVs) on BOC, and enhances the interaction between the catalyst with CO 2 and H 2 O molecules, hence greatly improving the CO 2 photoreduction activity of OH-CN/BOC. This work provides new insights and potential strategies for constructing high-quality interfacial heterojunctions with strong chemical bonds to facilitate the photocatalytic performance. [ABSTRACT FROM AUTHOR]