Tailoring well-ordered, highly crystalline carbon nitride nanoarrays via molecular engineering for efficient photosynthesis of H2O2

Small-scale on-site artificial photosynthesis of H2O2 from O2 and H2O is an ideal sustainable route. In particularly, g-C3N4 is a very popular catalyst, nevertheless, its photocatalytic activity is severely inhibited by the random migration and rapid recombination of photogenerated carriers. Herein, a well-ordered highly-crystalline g-C3N4 nanoarray with conjugated electron donor-acceptor structure (denoted as PDI/CNA) is rationally designed for efficient H2O2 production to imitate the photosynthesis of natural plants. Both experimental and DFT investigations demonstrate that the tailored PDI/CNA effectively improve charges utilization via eliminating deep defect trapping sites, and reduce its Gibbs free energy (ΔG) of rate-determining step (*HOOH→H2O2). As a result, the optimized PDI/CNA exhibits a superior H2O2 production rate of 1605.32 μmol g−1 h−1 and a high apparent quantum yield of 27.18% (λ = 400 nm). This work sheds light on promoting H2O2 photosynthesis by regulating the crystalline structure of g-C3N4 and rationally designing spatially separated redox centers. [Display omitted] •Photosynthesis of H2O2on-site production via 2e- oxygen reduction reaction.•Well-ordered highly-crystalline g-C3N4 nanoarray for efficient charges utilization.•Conjugated electron donor-acceptor structure for spatially separated redox centers.•Reduced Gibbs free energy (ΔG) of rate-determining step (*HOOH→H2O2).•Superior H2O2 production rate of 1605.32 μmol g−1 h−1 and AQY of 27.18% (λ = 400 nm).