Enlarging the π-conjugation system of carbon nitride for boosting hydrogen peroxide generation

Heterojunction engineering of graphitic carbon nitride (CN) was considered as a facile and efficient approach to boost photocatalytic hydrogen peroxide (H2O2) 2 O 2 ) generation. However, photocatalytic H2O2 2 O 2 generation over CN/ carbon fiber (CF) heterojunction is still challenging due to the rapid transfer and recombination of photo- generated charges. To solve this problem, a novel sulfur/nitrogen-self-doped carbon fibers (CFS,N), S,N ), derived from poly(2-acrylamido-2-methylpropane sulfonic) (AMPS)-grafted cellulose nanofibers as an efficient electron mediate was herein engineered onto CN skeleton (CN/CFS,N) S,N ) for achieving high-performance H2O2 2 O 2 production. The as-synthesized CN/CFS,N S,N nanocomposites exhibit an efficient H2O2 2 O 2 production rate of 1.31 mmol center dot L-1 center dot h- 1,-1 center dot h- 1 , which is 6.0 and 1.3 times higher than that of pure CN (0.22 mmol center dot L-1 center dot h-1)-1 center dot h- 1 ) and CN/CF (0.99 mmol center dot L-1 center dot h-1),-1 center dot h- 1 ), respectively, which also significantly outperforms recently-reported CN-based photocatalysts. Based on the experimental results and density functional theory (DFT) simulation, the CF S,N with S/N-doped carbon can act as an ultrafast electronic mediate for directional electron transport, which facilitates interfacial carrier transfer between CN and CFS,N. S,N . More importantly, beneficially from the interfacial electron redistribution via the pi-conjugation of CFS,N, S,N , the molecular oxygen (O2) 2 ) is highly activated to orderly drive sequential one-electron two-step O2-to-H2O2 2-to-H 2 O 2 conversion. This study presents a promising design of cellulose-derived carbon, which efficiently regulates the charge transfer and separation of CN-based photocatalysts for significantly enhanced H2O2 2 O 2 production.