Work

Synergistic Elimination of Chlorophenols Using a Single-Atom Nickel with Single-Walled Carbon Nanotubes: The Roles of Adsorption, Hydrodechlorination, and the Electro-Fenton Process

Year: 2024

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Electrocatalytic degradation enables the efficient treatment of chlorinated pollutants (COPs); however, its application has been significantly hindered by the large amounts of unsafe intermediate products. In this study, we present a single-atom nickel with single-walled carbon nanotubes (SWCNTs) as an electrochemical reactor for the complete elimination of chlorophenols. Distinct products and reductive mechanisms were observed for Ni–N–C compared to Cu–N–C. Ni–N–C incorporation has a novel degradation pathway for efficient chlorophenol degradation involving hydrodechlorination and the electro-Fenton process. Most importantly, the weak adsorption between the chlorophenols and the SWCNTs promoted their dechlorination by the attached active atomic hydrogen (H*) formed on the Ni–N–C. Meanwhile, the SWCNTs improved the reduction of O 2 to H 2 O 2, which was subsequently decomposed by Ni–N–C to form hydroxyl radicals (·OH) for phenol oxidation. As a result, the degradation rate of 4-chlorophenol was increased by 5 and 10 times compared with those of the Ni–N–C and SWCNTs alone, respectively. The first-order reaction rate constant was 2.7 h –1, and the metal mass kinetics constant was 1956.5 min –1 g –1 . Aromatic COPs containing benzene rings could be degraded, but chloroacetic acids could not. This study demonstrates a new design for multifunctional electrochemical degradation that functions via dechlorination and the ·OH activation mechanism.

Source: ACS Omega

DOI: 10.1021/acsomega.4c04289