Near-Infrared Light-Driven Photocatalytic Reforming Lignocellulose into H₂ and Chemicals over Heterogeneous Carbon Nitride

Abstract

Photocatalytic reforming of lignocellulose and water (H2O) into different value-added chemicals and hydrogen (H2) under near-infrared (NIR) light irradiation is still a huge challenge, owing to an insurmountable conflict between the narrow energy breadth of NIR and the high energy barrier for lignocellulose oxidation and H2O reduction. To break through this contradiction, we designed metal-free two-dimensional graphitic carbon nitride (g-C3N4) with carbon ring incorporation (g-C3N4–Cx) and realized NIR-driven simultaneous photocatalytic reforming of lignocellulose and H2 production. We disclosed the existence of an intermediate-band (IB) in g-C3N4–Cx, which is related to the electronic polarization area induced by incorporation of carbon rings according to valence-band spectra, UV–vis–NIR DRS spectra, transient photocurrent response, electron paramagnetic resonance, and electron spin resonance. The intermediate-band in g-C3N4–Cx not only extends the spectral absorption range but also promotes the photogenerated charge carrier separation due to the polarization charge density distribution. Therefore, our work could provide an effective and promising perspective to design NIR spectrum responsive photocatalysts to realize photocatalytic reforming of lignocellulose and H2 generation.