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

Solar-driven hydrogen peroxide (H2O2) production presents unique merits of sustainability and environmental friendliness. Herein, highly efficient solar-driven H2O2 production through dioxygen reduction is achieved by employing polymeric carbon nitride (PCN) framework with sodium cyanaminate moiety (PCN-NaCA), affording a superior H2O2 production rate of 175 μmol/h on 10 mg photocatalyst and a notable apparent quantum yield of 27.6% at 380 nm. The overall photocatalytic transformation process is systematically analyzed using various steady-state/transient spectroscopic and computational methods. The presence of sodium cyanaminate moiety in PCN-NaCA induces the following multiple effects: enhancing photon absorption, creating the coexistence of p-type and n-type domains, strengthening surface adsorption of dioxygen, and favoring highly selective 2e− ORR. In particular, the adsorption of dioxygen on PCN-NaCA 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.