Yang Pu, Ma Jing, Yang Kai, Zhang Daotong, Zhu Penghui, Chen Weimin, Bi Xiaotao, Jiang Feng
Sustainable Functional Biomaterials Laboratory, Department of Wood Science, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
Small. 2025 Jun;21(25):e2501162. doi: 10.1002/smll.202501162. Epub 2025 Apr 27.
Pore structure engineering of biocarbon is crucial for enhancing its performance. Herein, a phase diagram-guided molten salt activation method is systematically developed to prepare biocarbon with a tunable pore structure at low temperature (500 °C). This strategy incorporates key activation variables on the phase diagram of binary salts, including salt type, ratio, phase partition, and operating temperature. Among various salts, ZnCl with a low melting point (≈290 °C) is selected as the "pioneering" primary salt to swell biomass precursor and create porous channels conducive to the ion diffusion of secondary salts. Based on the liquid-solid equilibrium curve, specific amounts of secondary salts can be dissolved into molten ZnCl, facilitating the delivery of secondary salt ions to the inner active sites. The carefully selected secondary salts with varied solubility, reactivity, and ionic sizes further enhance pore creation (reaching a specific surface area of 2491 m g) and regulate pore sizes by catalytic reactions and pore filling. The understanding of the underlying ion diffusion and pore evolution mechanism (formation, growth, and stabilization) in binary molten salt systems provides a unique and versatile guide for producing biocarbon with tunable pore structure at low temperatures, supporting applications including energy storage and carbon capture.
生物炭的孔结构工程对于提高其性能至关重要。在此，系统地开发了一种相图引导的熔盐活化方法，以在低温（500°C）下制备具有可调孔结构的生物炭。该策略纳入了二元盐相图上的关键活化变量，包括盐类型、比例、相分配和操作温度。在各种盐中，选择熔点低（≈290°C）的ZnCl作为“先驱”主盐，以使生物质前驱体膨胀并创建有利于二次盐离子扩散的多孔通道。基于液-固平衡曲线，特定量的二次盐可溶解于熔融的ZnCl中，促进二次盐离子向内部活性位点的传递。精心选择的具有不同溶解度、反应性和离子尺寸的二次盐进一步增强了孔的形成（比表面积达到2491 m²/g），并通过催化反应和孔填充来调节孔径。对二元熔盐体系中潜在的离子扩散和孔演化机制（形成、生长和稳定）的理解为在低温下生产具有可调孔结构的生物炭提供了独特且通用的指导，支持包括能量存储和碳捕获在内的应用。
