Rejoint of Carbon Nitride Fragments into Multi-Interfacial Order-Disorder Homojunction for Robust Photo-Driven Generation of H2O2

Abstract

Photocatalytic technology based on carbon nitride (C3N4) offers a sustainable and clean approach for hydrogen peroxide (H2O2) production, but the yield is severely limited by the sluggish hot carriers due to the weak internal electric field. In this study, a novel approach is devised by fragmenting bulk C3N4 into smaller pieces (CN-NH4) and then subjecting it to a directed healing process to create multiple order-disorder interfaces (CN-NH4-NaK). The resulting junctions in CN-NH4-NaK significantly boost charge dynamics and facilitate more spatially and orderly separated redox centers. As a result, CN-NH4-NaK demonstrates outstanding photosynthesis of H2O2 via both two-step single-electron and one-step double-electron oxygen reduction pathways, achieving a remarkable yield of 16675 µmol h–1 g–1, excellent selectivity (> 91%), and a prominent solar-to-chemical conversion efficiency exceeding 2.3%. These remarkable results surpass pristine C3N4 by 158 times and outperform previously reported C3N4-based photocatalysts. This work represents a significant advancement in catalyst design and modification technology, inspiring the development of more efficient metal-free photocatalysts for the synthesis of highly valued fuels.