# Remote Modulation of Single‐Atom Catalyst Boosts High‐Valent Cobalt–Oxo Species Generation for Water Purification and Detoxification

## TL;DR

A new phosphorus-doped cobalt catalyst boosts the production of a powerful chemical for water purification, making it more efficient and safer.

## Contribution

A phosphorus-doped cobalt single-atom catalyst is developed to enhance high-valent cobalt–oxo species generation for water purification.

## Key findings

- P-doping increases the turnover frequency of the cobalt center by 3.5 times and the steady-state concentration of Co(IV)═O by 2.7 times.
- A continuous-flow reactor based on the catalyst achieves over 87% contaminant removal after 24 h of operation.
- Treated wastewater shows low cytotoxicity and genotoxicity, enhancing water safety.

## Abstract

With a high redox potential and long half‐life, high‐valent cobalt–oxo species (Co(IV)═O) hold promise for water purification by eliminating persistent contaminants. However, the inefficient and unsustainable generation of Co(IV)═O limits its practical application. In this work, a phosphorus (P)‐doped cobalt single‐atom catalyst (Co─N6/C─P) is developed, where P‐substituted nitrogen (N) atoms are coordinated to the cobalt site at meta‐positions. This remote modulation reduces the charge density of the cobalt site and positively shifts the d‐band center of the cobalt atom, thereby lowering the energy barrier for Co(IV)═O generation. The P‐doping increases the turnover frequency of the cobalt center by 3.5 times and the steady‐state concentration of Co(IV)═O by 2.7 times. The (Co─N6/C─P)/peroxymonosulfate (PMS) system exhibits a pollutant degradation kinetic constant three times higher than that of Co─N6/C, surpassing most reported single‐atom catalytic PMS systems. A continuous‐flow reactor based on Co─N6/C─P achieves over 87% contaminant removal after 24 h of operation. The treated real wastewater exhibits exceptionally low cytotoxicity (2.96 mg‐phenol L−1) and genotoxicity (0.08 µg‐4‐NQO L−1) to mammalian cells, enhancing water safety. This study presents a reliable approach for the removal of persistent contaminants and the reduction of toxicity through efficient Co(IV)═O generation enabled by a remote modulation strategy.

This study develops a phosphorus‐doped cobalt single‐atom catalyst that enhances high‐valent cobalt–oxo species generation for water purification. This atomic‐level tuning boosts the catalyst's activity by 3.5 times, enabling efficient pollutant degradation. A continuous‐flow reactor achieves high, long‐term removal efficiency, producing water with low toxicity, offering a promising approach for environmental purification.