Modulating Electronic Structure Engineering of Atomically Dispersed Cobalt Catalyst in Fenton-like Reaction for Efficient Degradation of Organic Pollutants

Abstract

Currently, the lack of model catalysts limits the understanding of the catalytic essence. Herein, we report the functional group modification of model single atom catalysts (SACs) with an accurately regulated electronic structure for accelerating the sluggish kinetics of the Fenton-like reaction. The amino-modified cobalt phthalocyanine anchored on graphene (CoPc/G-NH2) shows superior catalytic performance in the peroxymonosulfate (PMS) based Fenton-like reaction with Co mass-normalized pseudo-first-order reaction rate constants (k obs, 0.2935 min –1 ), which is increased by 4 and 163 times compared to those of CoPc/G (0.0737 min –1 ) and Co3O4/G (0.0018 min –1 ). Density functional theory (DFT) calculations demonstrate that the modification of the −NH2 group narrows the gap between the d-band center and the Fermi level of a single Co atom, which strengthens the charge transfer rate at the reaction interface and reduces the free energy barrier for the activation of PMS. Moreover, the scale-up experiment realizes 100% phenol removal at 7200-bed volumes during 240 h continuous operation without obvious decline in catalytic performance. This work provides in-depth insight into the catalytic mechanism of Fenton-like reactions and demonstrates the electronic engineering of SACs as an effective strategy for improving the Fenton-like activity to achieve the goal of practical application.

Active Center Size-Dependent Fenton-Like Chemistry for Sustainable Water Decontamination

“…Differences in the size-effect-induced contribution of radical mechanisms are discussed later. Adding tert -butanol (TBA) and methyl alcohol (MeOH) showed negligible inhibitory effects on SIZ degradation in all catalytic systems, and the absence of O 2 •– collectively verified the dominant role of nonradical pathways. , Furfuryl alcohol (FFA), a specific inhibitor of 1 O 2 , was added to the CoSA/PMS system and SIZ degradation declined, demonstrating the critical role of 1 O 2 . 2,2,6,6-Tetramethyl-4-piperidinyloxyl (TEMP) was employed to capture 1 O 2 in electron paramagnetic resonance (EPR) analysis. , The 1 O 2 intensity of the CoSA/PMS system was nearly 11.2 times stronger than that of the NC/PMS system, indicating that introducing Co–N 4 active sites enhanced the generation of 1 O 2 tremendously (Figure g).…”

Hydrogen Peroxide as an Ideal Electron Donor for Long-Lasting Fenton Chemistry: Strong Enhancement of Fe(III) Activity by Heteroatom-Doped Nanocarbons

“…The Fenton reaction (Fe­(II) and H 2 O 2 ) has attracted great attention in water treatment research owing to its high reaction rate, low toxicity, and mild reaction conditions. − Fe­(II) can react with H 2 O 2 to produce the highly active hydroxyl radical ( • OH; eq ) which can powerfully oxidize most organic contaminants in a nonselective manner due to its high oxidation capability ( E 0 ( • OH/OH – ) = 2.73 V), , while Fe­(III) produced in situ can regenerate Fe­(II) by oxidizing H 2 O 2 (eq ). − However, the reaction rate constant of H 2 O 2 -induced Fe­(III) reduction (eq , k = 9.1 × 10 –7 M –1 ·s –1 ) is 8 orders of magnitude smaller than that of H 2 O 2 -induced Fe­(II) oxidation ( k = 40–80 M –1 ·s –1 ).…”

Synergetic Manipulation Mechanism of Single-Atom M–N4 and M–OH (M = Mn, Fe, Co, Ni) Sites for Ozone Activation: Theoretical Prediction and Experimental Verification

“…Carbon-based single-atom catalysts (SACs) have aroused increasing interest in the fields of wastewater treatment and environmental remediation in the past few years due to their merits of exceptional atomic utilization, high selectivity, and structural stability. − In addition, SACs can be used to establish ideal catalytic systems to investigate the interactions between the reactant molecules and the active sites of isolated metal atoms on catalyst surfaces. − It has been widely reported that such catalysts could exhibit excellent removal performance of aqueous pollutants through modulating the catalytic reaction pathways in the Fenton-like systems, e.g., radical and nonradical pathways. − The remarkable catalytic performance of the carbon-based SACs in Fenton-like reactions can also inspire their extended application in other AOP systems.…”