Almost 100 % Peroxymonosulfate Conversion to Singlet Oxygen on Single‐Atom CoN₂₊₂ Sites

Abstract

Single‐atom CoN4 active sites have demonstrated excellent efficiency in peroxymonosulfate activation. However, the identification of CoN4 active sites and the detailed singlet oxygen generation mechanism in peroxymonosulfate activation remains ambiguous. We demonstrate a strategy to regulate the generation of reactive oxygen species by atomically dispersed cobalt anchored on nitrogen‐doped carbon. As indicated by experiment and DFT calculations, CoN2+2 was the active site and singlet oxygen was the predominant reactive oxygen species with a proportion of 98.89 %. Spontaneous dissociation of adsorbed peroxymonosulfate on the CoN2+2 active sites was energetically unfavorable because of the weakly positive Co atoms and CoN2+2 coordination, which directed PMS oxidation by a non‐radical pathway and with simultaneous singlet oxygen generation. The generated singlet oxygen degraded several organic pollutants with high efficiency across a broad pH range.

Mineral Modulated Single Atom Catalyst for Effective Water Treatment

“…[ 20,54 ] However, which one dominates is still not clear even in the highly similar Co SACs/PMS systems. [ 14,20–22,54 ] Herein, the involved reaction mechanisms were discriminated by in situ EPR and scavenging experiments. A set of characteristic signals for DMPOSO 4 •− , DMPO • OH, and TEMP −1 O 2 adducts observed in Figure 4d,e reveal that the radical and nonradical reaction processes might both occur in p‐CoSi 1 N 3 @D/PMS system.…”

“…In fact, the electron transfer between PMS molecules and Co site was regarded as the rate determining process in the nonradical pathway. [ 14,18 ] To gain deep insights into the relationship between electron transfer, PMS activation properties and spatial coordination configuration of cobalt single atom active sites, DFT calculations were further carried out. Based on the formation energy calculation results, we chose the most energetically favorable structures (CoN 4 ‐PdN‐IE and CoSi 1 N 3 ‐PdN‐IE) to discuss the effect of Si substitution on PMS activation ( Figure a,b; Table S7, Supporting Information).…”

“…[20,54] However, which one dominates is still not clear even in the highly similar Co SACs/PMS systems. [14,[20][21][22]54] Herein, the involved reaction mechanisms were discriminated by in situ EPR and scavenging experiments. A set of characteristic signals for DMPOSO 4…”

“…[ 7–10 ] In recent years, Co single atom catalysts (SACs), as one of the most emerging kinds of heterogeneous catalysts, possess special electronic structure, utmost Co atom utilization efficiency, and uniformly isolated Co active sites. [ 11–17 ] Such unique properties make Co SACs an attractive platform to bridge the gap between homogeneous and heterogeneous PMS activation. [ 1,11,17–20 ]…”

Activity Trends and Mechanisms in Peroxymonosulfate‐Assisted Catalytic Production of Singlet Oxygen over Atomic Metal‐N‐C Catalysts

“…[21,22] In recent years,c arbon-supported atomic metal-N-C catalysts have been used in the fields of energy, [23][24][25][26] biology, [27] and environment. [3,28] Therefore,t he carbon-supported atomic metal-N-C catalysts with definite catalytic sites and high activity are promising candidates to combat organic contaminants in AOPs.I nc ontrast, less attention has been paid to carbon-supported atomic metal-N-C catalysts with different transition metal centers and to the disclosing of the nature of the transition metals on the PMS-assisted catalytic activities and trends toward ROS production. [1,[29][30][31][32] Therefore,i ti s imperative to synthesize metal-N-C catalysts with uniform structures and atomic metal sites to comprehensively analyze structure-performance relationships and uncover their cata-lytic activity trends and reaction mechanisms in PMS-assisted catalytic ROSproduction.…”