Potassium/cyano group co-incorporation promotes 2e− ORR selectivity in porous ultrathin carbon nitride for photocatalytic H2O2 production

Abstract

Photocatalysis is a promising strategy for the production of H2O2, but the promotion of 2e− ORR selectivity remains a challenging goal in this field. Herein, Potassium (K+), cyano groups (-C≡N) and porous ultrathin structures were introduced into g-C3N4 simultaneously by the hyphenated technique of gas template method and molten salt-assisted method. The K+ and -C≡N can broaden the light absorption range, improve the reduction ability and promote electron transfer of the catalyst. Additionally, the presence of a permeable ultrathin structure plays a crucial role in improving the specificity of the 2e− oxygen reduction reaction (ORR). Benefiting from the multiple advantages, the H2O2 yield of K+ intercalated cyano-rich porous ultrathin g-C3N4 (KUCN) reached 781.39 μM with an extraordinary 2e− ORR selectivity of 94.5% (0.30 V vs. RHE). Overall, this study presents a practical approach for designing catalysts based on g-C3N4 that exhibit a high selectivity for the 2e− ORR reaction.