▎ 摘　　要

Effective biomass waste utilization to alleviate the environmental pollution is significant for the sustainable development of human society and nature. Herein, in this work, waste grapefruit peels with wrinkled hollow structure and abundant reactive groups were used to fabricate a series of multifunctional nickel nanoparticles embedded in nitrogen self-doped graphene-like carbon nanocomposites (Ni-x @NGC, where "x" represents the amount of Ni) via a simple and convenient impregnation-carbonization strategy. The reaction temperature and Ni amount were tuned to investigate their influences on structure and performance. When evaluated as electrocatalysts in alkaline oxygen evolution and hydrogen evolution reactions, the optimal Ni-0.20 @NGC-700 exhibits low overpotentials of 350 and 165 mV and moderate Tafel slopes at current densities of 20 and 10 mA cm(-2), respectively. Also, the as-prepared Ni-0.20 @NGC-750 shows an excellent magnetic ability with a high saturation magnetization strength of 47 emu g(-1) and a low coercivity of 83 Oe. This study may provide a simple and sustainable approach for the development of environmental and cost-effective nanocomposites with excellent electrical and magnetic performance.