Ultrahigh Photocatalytic Oxygen Reduction to Hydrogen Peroxide by a True Oxygen-Bridged Heptazine Polymer
Venugopala Rao Battula, Bhawna Rawat, Kamalakannan Kailasam
Abstract
Solar-H 2 O 2 production presents an eco-friendly and sustainable strategy over the existing anthraquinone process. The present photocatalytic systems suffer from low two-electron oxygen reduction reaction (ORR) selectivity. The current study reports an easy approach to produce a true oxygen-bridged heptazine polymer with periodic arrangement of oxygen atoms (CNO) by introducing C–O–C bridging species through the right precursor selection. The C–O–C species in CNO dramatically promotes ORR compared to the benchmark carbon nitride synthesized from melamine (CNM), which has been proved by electrochemical analysis. To our surprise, the CNO has produced 1.5 mmol/g of H 2 O 2 after 4 h in natural sunlight, which is the highest among the existing carbon-nitride-based photocatalysts. In addition, the challenging biomass-derived chemicals, glycerol, glucose, and 1,2-propanediol were also utilized as sacrificial electron donors in H 2 O 2 production to synthesize fine chemicals. Overall, this work provides an easy approach to tune the two-electron ORR to boost H 2 O 2 production and paves the way for practical solar-H 2 O 2 production from biomass using polymeric O-bridged heptazines (CNO).