Intrinsic strain of defect sites steering chlorination reaction for water purification.

Carbon nanotube (CNT)-based heterogeneous advanced oxidation processes (AOPs) used for water purification have been exploited for several decades. Many strategies for modifying CNTs have been utilized to improve their catalytic performance in remediation processes. However, the strain fields of the intrinsic defect sites on CNT steering AOPs (such as chlorination) have not yet been reported. Here, we explored the strained defect sites for steering the chlorination process for water purification. The strained defect sites with the elongated sp hybridized C-C bonds boost electronic reactivity with the chlorine molecules via the initial Yeager-type adsorption. As a result, the reactive species in chlorination can be regulated on demand, such as the ratio of high-selectivity ClO ranging from 38.8% in conventional defect-based systems to 87.5% in our strain-dominated process, which results in the generation of harmless intermediates and even deep mineralization during 2,4-DCP abatement. This work highlights the role that strain fields have on controlling the extent of chlorination reactions.