Liquefiable biomass-derived porous carbons and their applications in CO2 capture and conversion

Abstract

Biomass-derived porous carbons (BPCs) have been explored as adsorbents for CO₂ capture and catalysts for CO₂ conversion, showing great potential in helping achieve “negative carbon emissions”. Traditionally, BPCs are derived from solid biomass such as forestry and agriculture residuals. They are limited in performance due to poor morphology control, uneven, low-active sites, and weak mechanical strength. Liquid or liquefiable biomass, such as carbohydrate solution, microalgae, and bio-oil, is an emerging class of porous carbon precursors. In recent years, their fluidity, miscibility and formability have been exploited, resulting in high-performance liquefiable biomass-derived porous carbons (LBPCs) with controllable particle size distribution, evenly distributed active sites and adjustable porosity. About 30% of adsorbents and catalysts are currently prepared from liquefiable biomass via tailorable synthesis; the rapid expansion of research calls for a comprehensive review. This review introduces the concept of liquefiable biomass precursors (LBPs) and summarizes LBPs’ specificity. We present a comprehensive account of the multi-scale design and functional synthesis methods, including sol–gel, reverse emulsion, hydrothermal carbonization and spray drying. We illustrate LBPCs’ performance in CO₂ capture and conversion, emphasizing the approaches to improve the CO₂ capture capacity and catalytic conversion efficiency by regulating the properties of LBPCs. The review concludes with a perspective on research and development needs for scaling up LBPC-based negative emission technologies (NET).