Cobalt Oxide on Boron-Doped Graphitic Carbon Nitride as Bifunctional Photocatalysts for CO<sub>2</sub> Reduction and Hydrogen Evolution
Jean C. Cruz, Gelson T. S. T. da Silva, Eduardo Henrique Dias, Diego S. D. Lima, Juliana A. Torres, Pollyana Ferreira da Silva, Cauê Ribeiro
Abstract
In this work, the prepared cobalt oxide decorated boron-doped g-C 3 N 4 (CoOx/g-C 3 N 4 ) heterojunction exhibits remarkable activity in CO 2 reduction (CO 2 RR), resulting in high yields of CH 3 COOH (∼383 μmol·g catalyst –1 ) and CH 3 OH (∼371 μmol·g catalyst –1 ) with 58% selectivity to C 2+ under visible light. However, the same system leads to high H 2 evolution (HER) by increasing the cobalt oxide content, suggesting that the selectivity and preference for the CO 2 RR or HER depend on oxide decoration. By comparing HER and CO 2 RR evolution in the same system, this work provides critical insights into the catalytic mechanism, indicating that the CoOx/g-C 3 N 4 heterojunction formation is necessary to foster high visible light photoactivity.