Waste biomass-derived biochar in adsorption-photocatalytic conversion of CO2 for sustainable energy and environment: Evaluation, mechanism, and life cycle assessment.

Biochar is an environmentally friendly material with great potential for carbon capture and storage. As the first of its kind, waste biomass-derived biochar was utilized to convert CO 2 into fuel in solar. Herein, among four representatives herbaceous, woody, sludge, and manure wastes, the pine sawdust-derived biochar produced the highest CO assisted by higher CO 2 adsorption, more than 10 times higher than that of graphene and activated carbon. The function groups of carbonyl and carboxyl on biochar controlled the CO 2 capture and solar conversion by decreasing adsorption and activation energies of CO 2 molecules. The biochar performed even better for 15% CO 2 /N 2 atmosphere, a typical CO 2 concentration in the flue gas, demonstrating its promising potential in waste gas resource utilization. The life-cycle assessment indicates that feedstock with more cellulose and lignin provide better environmental and economic benefits. The work highlights a sustainability pathway for waste biomass-derived biochar in CO 2 -to-fuel under ambient conditions. [Display omitted] • Waste biomass-derived biochar show excellent adsorption-photocatalytic CO 2. • Biochar have promising applications in utilization CO 2 in the industrial flue gas. • Carboxyl and carbonyl functional groups of biochar are the key to CO 2 conversion. • Waste biomass with more cellulose and lignin favor higher environmental benefits. [ABSTRACT FROM AUTHOR]