Structure-property-function Relationships of Wood-Based Activated Carbon in Energy and Environment Materials

Wood-based activated carbon, with hierarchical porous structure, mechanical stability and durability, and anisotropy, demonstrates unique structure-property-function relationships in energy and environment materials. In view of these achievements in recent years, a critical review and outlook is highly desirable. This paper attempts to fundamentally better understand the evolution of natural wood into activated carbon by discussing the structure of different wood species at various scales, and the effect of physical and chemical modifications on their morphology, microstructure and performance when used for pollutant adsorption, catalytic degradation, gas storage, and supercapacitors. With more cell types and scales, hardwood-based activated carbon demonstrates larger amounts of active sites and interpenetrating channels for mass transfer than that from softwood. Surface modification with polar functional groups improves the performance and stability in energy conversion and environmental remediation. However, the challenges on over-consumption of energy for procedure, uncontrollable mesopore/micropore ratio and surface modification for large scale bulk wood put a pressing need to develop green and controllable carbonization technologies. In addition, in situ corrosion and surface energy driven molecular modification combined with emerging nanotechnologies to tune the microstructure and properties may be viable strategies, which will promote the wood-based activated carbon to a sustainable future.