Surface reconstruction of natural wood-derived, monolithic chainmail catalyst enables robust water purification.

Chainmail catalysts, characterized by carbon layer-encapsulated active sites embedded within hierarchically porous carbon matrices, represent an optimal strategy for enhancing catalytic stability in the activation of peroxymonosulfate (PMS) for the degradation of organic pollutants. However, these powder catalysts face challenges such as agglomeration, sluggish diffusion kinetics, and difficulties in separation. In this study, we transformed low-cost natural wood into a monolithic, self-supported chainmail catalyst, Co@CW, by embedding Co nanoparticles within hierarchically porous carbonized wood. The Co@CW-800 chainmail catalyst effectively activated PMS through a dominant free radical pathway, achieving a high tetracycline (TC) removal efficiency of 94.5 % within 30 min. Furthermore, Co@CW-800 exhibited good adaptability under various conditions and maintained its high degradation efficiency over multiple cycles due to the surface reconstruction effect. The chainmail catalyst Co@CW-800 activated PMS to degrade TC via three primary pathways and generated twelve intermediate products. Moreover, toxicity evaluations indicated a reduction in toxicity after TC degradation by the Co@CW-800/PMS system. This study presents an efficient, stable, and recyclable self-supported chainmail catalyst system, establishing a foundation for water pollution control and advancing environmentally friendly advanced oxidation technologies.