Synthesis of biomass-based carbon aerogels in energy and sustainability.

Carbon aerogels are 3D hierarchical multiscale porous materials with outstanding physicochemical properties such as high specific surface area, low density, high porosity, excellent electrical conductor, good chemical stability, hydrophobicity, and adjustable surface chemistry among others. Unlike conventional carbon aerogels, biomass-based carbon aerogels are economical, environmentally friendly and have nigh inexhaustible precursors, which have generated extensive interest and exhibited outstanding electrocatalysis and adsorption/absorption performance. In this review, we mainly summarized the four main kinds of biomass (cellulose, chitosan, lignin and tannin) as carbon aerogel precursor, and discussed in detail their resource, constitute and optimized synthesis mechanism. Further advice was also given for better utilization of biomass as carbon aerogel precursors.