Electrochemical assisted single atom copper modified novel nitrogen doped porous carbon mediated catalytic activity based on D-band center modification: Rapid degradation of enoxacin

Persulfate (PMS) is an excellent free radical initiator with selective degradation of organic pollutants . This article presents the preparation of a high-performance Cu-SA@NCA(Single atom copper modified nitrogen doped aerogel carbon) electrocatalyst with adjustable interfacial separation enhancement effect for the first time. Under the optimal process parameters, the removal rates of ENO , COD , and TOC obtained after 5 min of reaction were 100 %, 73.41 % and 55.15 %, respectively. The average energy consumption was saved by 59.63∼123.25 kWh/kg ENO. After 6 cycles of degrading ENO wastewater, the removal rate of ENO only decreased by 8.55 %. It was demonstrated through characterization such as high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), X-ray absorption near edge structure (XANES), and Fourier Transform Extended X-ray Absorption Fine Spectroscopy (FT-EXAFS) that the single atom copper loaded on the Cu-SA@NCA surface is tightly bound to N in NCA through Cu-N 4 bond bridges, promoting the formation of double electron centers on the catalyst surface. The particle electrode catalyst significantly enhances the PMS activation process over a wide pH range and can accelerate the degradation of enoxacin (ENO). As the reaction center for PMS adsorption and activation, Cu-N 4 has a lower charge transfer resistance and can attract PMS to the catalyst surface, resulting in a higher current response in the PMS system. Organic pollutants release electrons through the carbon matrix of carbon based catalysts and transfer them to Cu-SA@NCA-PMS, promoting PMS activation and the formation of high valence copper ions , enhancing the degradation of pollutants. Density functional theory (DFT) further indicate that the regulatory effect of N on the electron distribution of Cu d orbitals is beneficial for the stretching and cleavage of Cu active centers by PMS, accelerating the process of SO 4 − · and ·OH generation rate, which is consistent with the results of XANES. In addition, during the degradation process of salt containing organic pollutants in PMS, Cu-SA@NCA exhibits strong resistance to inorganic ions , natural organic matter , and pH value. This work developed a new catalyst that selectively produces SO 4 − · and ·OH with 97.46 % selectivity, achieving high selectivity and efficiency in degrading pollutants.