Atomically Dispersed Cobalt Sites on Graphene as Efficient Periodate Activators for Selective Organic Pollutant Degradation

Abstract

Pollutant degradation via periodate (IO 4 − )-based advanced oxidation processes (AOPs) provides an economical, energy-efficient way for sustainable pollution control. Although single-atomic metal activation (SMA) can be exploited to optimize the pollution degradation process and understand the associated mechanisms governing IO 4 − -based AOPs, studies on this topic are rare. Herein, we demonstrated the first instance of using SMA for IO 4 − analysis by employing atomically dispersed Co active sites supported by N-doped graphene (N-rGO-CoSA) activators. N-rGO-CoSA efficiently activated IO 4 − for organic pollutant degradation over a wide pH range without producing radical species. The IO 4 − species underwent stoichiometric decomposition to generate the iodate (IO 3 − ) species. Whereas Co 2+ and Co 3 O 4 could not drive IO 4− activation; the Co−N coordination sites exhibited high activation efficiency. The conductive graphene matrix reduced the contaminants/electron transport distance/resistance for these oxidation reactions and boosted the activation capacity by working in conjunction with metal centers. The N-rGO-CoSA/IO 4 − system exhibited a substrate-dependent reactivity that was not caused by iodyl (IO 3• ) radicals. Electrochemical experiments demonstrated that the N-rGO-CoSA/IO 4 − system decomposed organic pollutants via electron-transfer-mediated nonradical processes, where N-rGO-CoSA/periodate* metastable complexes were the predominant oxidants, thereby opening a new avenue for designing efficient IO 4 − activators for the selective oxidation of organic pollutants.

Graphene Oxide-Supported Three-Dimensional Cobalt–Nickel Bimetallic Sponge-Mediated Peroxymonosulfate Activation for Phenol Degradation

“…This may partially ascribe to the leached metal ions such as Co and Ni, as they may present some broad signals in the background. Also, nonradicals can also oxidize DMPO, resulting in the formation of 5,5-dimethyl-1-pyrrolidone-2-oxyl (DMPO-X) . Therefore, four active substances were involved in the degradation of phenol, and 1 O 2 played the most important role among them.…”

“…Also, nonradicals can also oxidize DMPO, resulting in the formation of 5,5-dimethyl-1-pyrrolidone-2-oxyl (DMPO-X). 47 Therefore, four active substances were involved in the degradation of phenol, and 1 O 2 played the most important role among them. The involved degradation mechanisms of the SCNGs/PMS system are shown in eqs 1−13.…”

Recent advances in metal-free catalysts for the remediation of antibiotics, antibiotic resistant bacteria (ARB), and antibiotic resistant genes (ARGs)

“…The Co-N coordination site was the active site for the catalytic oxidation reaction and signicant electron transfer was Fig. 6 H 2 O 2 decomposition by rGO nanosheets ((a) with permission from the American Chemical Society), 59 the production of SO 4 c À by rGO activated PMS ((b) with permission from the American Chemical Society), 33 charge density difference of PI adsorbed on CoN 4 and CoN 2 O 2 , top view (c and e) and side view (d and f), with permission from the American Chemical Society, 60 and synthesis routes of 3D rGO and selective removal of phenolic compounds in a 3D rGO/PDS system ((g) with permission from the American Chemical Society). 61 veried between the PI and Co centers by the charge density analysis (Fig.…”

“…For example, the k app of BPA with N-doped rGO/PMS was 0.71 min −1 , which was nearly 700 times that by the rGO/PMS process (0.001 min −1 ). 62 For the first time, Long et al 60 used N-doped rGO with abundant atomically dispersed Co sites for PI activation. The Co–N coordination site was the active site for the catalytic oxidation reaction and significant electron transfer was verified between the PI and Co centers by the charge density analysis (Fig.…”

Atomically Fe doped hollow mesoporous carbon spheres for peroxymonosulfate mediated advanced oxidation processes with a dual activation pathway

“…24,29,30 Furthermore, the rigid framework allows HMCS to act as suitable "cages" to shorten the migration distance between the target pollutant and ROS, improving the catalytic activity. [31][32][33][34] Taken together, it is reasonable to assume that SACs anchored on nitrogen-doped HMCS could be promising candidates to act as robust catalysts for AOPs. To date, the application of SACs anchored on N-doped HMCS in AOPs has rarely been reported.…”