Polydopamine and Barbituric Acid Co‐Modified Carbon Nitride Nanospheres for Highly Active and Selective Photocatalytic CO2 Reduction

Carbon nitride nanospheres modified with polydopamine and barbituric acid (BA‐CNS‐PDA) were successfully prepared by following a template‐copolymerization and post‐modification strategy. The photocatalytic CO 2 reduction was carried out using BA‐CNS‐PDA as photocatalyst, Co(bpy) 3 2+ as the cocatalyst and TEOA as the sacrificial electron donor. The productivity and selectivity for photocatalytic reduction of CO 2 to CO on BA 20 ‐CNS‐PDA 15 under visible‐light for 4 h were measured to be 158 µmol and 86.0 %, respectively, and are nearly 5 and 1.5 times, respectively, that of unmodified CNS. Optical characterization indicates that the outstanding photocatalytic CO 2 reduction performance is a result of improved charge separation and transfer due to copolymerization with barbituric acid and enhanced visible light absorption due to polydopamine. The adsorption isotherm of CO 2 demonstrates that polydopamine increase CO 2 adsorption capacity and promote CO 2 activation due to the presence of the amino groups.