▎ 摘　　要

Defect engineering is an effective path to prune the performance of photocatalysts but are rarely reported in graphene-semiconductor composites. Here, the few-layered graphene materials with different defect contents are obtained through facile alkali-assisted "cutting-thin" technique. Meanwhile, the monolayer graphene with low defect content is also synthesized on a variety of biomasses via the same uncomplicated process. Importantly, the defects in few-layered graphene have been established as an important platform to research the relationship between catalytic activity and defect. Therefore, a series of graphene-GCN photocatalysts with different defect contents were prepared by the wet-chemistry synthesis process. Compared to more defects and less content of defects, the optimal defect content displays greatly improved H-2 production rate. Therefore, a suitable defect content in graphene can not only increase the photogenerated electron transport, but also hinder the photoinduced electron recombination. This successful application of defect engineering is awaited to furnish guidance for intelligent contexture of graphene-based photocatalyst for extensive uptake in other directions, including photoelectrochemical sensors, dye-sensitized solar cells, and photocatalytic CO2 reduction. (C) 2021 Elsevier B.V. All rights reserved.