Identification and Analysis of Multiple Factors Controlling Solar-Driven H 2 O 2 Synthesis Using Engineered Polymeric Carbon Nitride

SummarySolar-driven hydrogen peroxide (H2O2) production presents unique merits of sustainability and environmental friendliness. Herein, highly efficient solar-driven H2O2 production through the reduction of dioxygen coupled with the oxidation of biomass-derived glycerol as a sustainable reductant was achieved by employing an unusual p-type polymeric carbon nitride (PCN) framework with sodium cyanaminate moiety (PCN-NaCA), which exhibited a highly enhanced production rate of 15.0 mmol H2O2 h−1 g−1(catal.) and a notable apparent quantum yield of 27.6% at 380 nm. The overall photocatalytic transformation process was systematically analyzed using various static/time-resolved spectroscopic and computational methods. The presence of sodium cyanaminate moiety in PCN-NaCA induced the following multiple effects: enhancing photon absorption, switching to p-type character with accumulating more electrons in the surface region, retarding radiative charge recombination, enhancing surface adsorption of O2, and favoring highly selective 2e− ORR. In particular, it was found that the adsorption of O2 (an electron acceptor) on PCN-NaCA actually enhances the population and lifetime of trapped electrons in the ps-ns time regime, which should have a notable synergic effect on oxygen reduction process. All of these unique properties of PCN-NaCA positively contribute to the extraordinary photoactivity of H2O2 production.