Synthesis of hierarchically porous carbon materials by zinc salts-assisted carbonization of biomass and organic solid wastes

Hierarchically porous carbons (HPCs) with multimodal pores have attracted considerable attention due to their unique physical and chemical properties and various application potentials in heterogeneous catalysis, environmental treatment, and energy storage and conversion. Herein, we report a general and simple zinc salts-assisted method for the synthesis of HPCs with varied porosity and chemical functionalities by the direct carbonization of diverse biomass and wastes. During the carbonization, zinc salts are thermally decomposed into nanoparticles that serve as in-situ templates to introduce nanopores in carbons. The prepared HPCs exhibit high specific surface areas (up to 2432 m2 g−1), large pore volumes (up to 4.30 cm3 g−1), and broad pore size distributions. Moreover, the zinc salts can be recovered and recycled, supporting the sustainable production of HPCs on large scale. The prepared HPCs-supported catalysts with atomically dispersed metal sites exhibit promising electrocatalytic performance for the oxygen reduction reaction.