▎ 摘　　要

Graphene has attracted tremendous interest for its applications in numerous fields. However, there remain challenges to the scalable and commercially viable production of graphene for practical applications. In this study we present a universal and solvent-free approach to preparing few-layer graphene flakes from various lowcost biomass precursors via a facile and scalable solvent-free shearing/graphitization method. The introduction of Fe3+ and Cl- into diverse biomass precursors during the shearing process enables the formation of graphene during the subsequent catalytic carbothermal graphitization reaction. The size of the obtained graphene flakes is generally determined by the shearing time and rate. The as-synthesized biomass-derived few-layer graphene flakes benefit from the relatively high Hall mobility (1.17 x 10(5) cm(2)/V center dot s), sheet resistance (0.36 k Omega/sq), and electrical conductivity (1.39 x 10(4) S/m). Its comparable conductivity value and ease of preparation make it a suitable support for many important technological applications, including as a suitable catalyst support for electrocatalytic oxygen reduction reactions. Moreover, there are many readily available sources of biomass for use as the precursor, and even biowaste precursors can be used. Therefore, this concise solvent-free shearing/ graphitization method has potential as a universal approach to the scalable synthesis of biomass-derived highquality graphene materials for a wide variety of applications.