Sustainable supercritical-mechanochemical process.

Zhang, Hao; Ren, Wen; Xiang, Qixuan; Liu, Zhiyuan; Zhang, Xianglong; Zhao, Yaping; Tan, Huijun · Nat Commun · 2026

basic_science · Level V

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Abstract

Mechanochemistry offers a route for converting metal oxides directly into metal organic frameworks (MOFs), ensuring maximal atomic utilization. Here, we have advanced reaction scope to the supercritical regime for establishing an integrated quasi-continuous synthesis, separation, and activation process (supercritical-mechanochemical process, SCM). Within SCM, supercritical CO<sub>2</sub> (SC CO<sub>2</sub>) facilitates a spatiotemporally uniform distribution of substoichiometric cosolvent (η < 0.2 μL·mg-<sup>1</sup>) across mechanochemical hot-spots, where its near-zero interfacial tension optimizes mass transfer efficiency and accelerates grinding-induced nucleation. The circulation of SC CO<sub>2</sub>-cosolvent enhanced the ability of metastable phases to form specific topological frameworks, either through monomer-crystalline interactions or intermediate transitions. A pilot-scale facility verified a rapid production rate from an initial input of 3.5 kg to the final product within 8-hour process cycle (space-time yield of 544.29 kg·m<sup>-3</sup>·d<sup>-1</sup>), along with ligand and cosolvent recovery rates reaching 42.66 wt% and 89.48 wt%, respectively. Techno-economic assessment underscored substantial cost advantages over conventional solvent-based methods, positioning SCM as a sustainable and competitive approach for scalable production.