Efficient photoreforming of lignocellulose into H2 and photocatalytic CO2 reduction via in-plane surface dyadic heterostructure of porous polymeric carbon nitride

Photoreforming of lignocellulose for sustainable H2 generation appears to be a good option at the time that biomass wastes are being degraded. Recently, polymeric carbon nitride (PCN) has emerged as a promising alternative for the photorefoming reaction, however, its photocatalytic performance is largely limited by its severe recombination of charge carriers. Here, we developed an approach, for the first time, to construct a curly-like carbon nitride nanosheets with the formation of in-plane surface dyadic heterostructure for steering the charge transfer and optimizing the electronic band structure. This PCN material shows superior photoreforming H2 evolved activity of 122.77 μmolh−1 (i.e. 4092 μmolh−1g−1) from the aqueous lignocellulose solution (using Pt as cocatalyst), 15.6 folds of pristine PCN under visible light irradiation, together with an apparent quantum efficiency (AQE) of 7.87% (λ = 420 nm). It enables the visible-light-driven conversion of several kinds of lignocellulose including the monosaccharides, disaccharides, hemicellulose, and cellulose. Additionally, when used as a photocatalyst for water splitting, it achieves a remarkable H2 production rate of 22043 μmolh−1g−1 (∼56.0 folds’ increases than pristine PCN) with a superior high AQE of 41.2%, as well as a high CO reduction rate of 56.3 μmolh−1 from the photocatalytic CO2 conversion, 24.5 times than pristine PCN. A curly-like carbon nitride nanosheets photocatalyst with the formation of surface dyadic heterostructure shows superior photoreforming of lignocellulose for H2 generation. [Display omitted] •Steering charge transfer via optimizing nucleation process by using a organic base.•Surface dyadic heterostructure enables efficient charge carriers separation.•Rose-leaf porous ultrathin nanosheets via hydrothermal process is fabricated.•Bifunctional HCN-NEA simultaneously reduce proton to H2 and oxidize lignocellulose.•HCN-NEA shows a high CO reduction rate of 56.3 μmolh−1 with enhanced 24.5 times.