Zero-dimensional N-doped carbon quantum dots and palladium co-modified titanium electrodes enhance the electrocatalytic degradation of oxytetracycline hydrochloride

Abstract

Reducing the amount of precious metals and improving their catalytic activities are difficult problems in the field of electrocatalysis. In this study, Pd/N-CQDs/Ti electrodes were prepared by introducing the N element into zero-dimensional carbon quantum dots and then compounded with Pd metal, and the electron transfer mechanism was explored. The results showed that the composite electrode degraded OTC up to 90.41% (60 min) at natural pH with an energy consumption of only 0.288 kWh/m3. The Pd/N-CQDs/Ti electrode formed a Pd-N-CQDs interface due to the electronic metal-carbon interaction (EMCI). In this, electrons are transferred from Pd to N, and the Pd-N interface plays a major role in hydrogen precipitation and the generation of atomic hydrogen. The generated H* ,·OH, and HClO all contribute to the degradation of OTC. According to the cycling experiments, the Pd/N-CQDs/Ti electrode showed good stability. When applied to OTC degradation in real water bodies, good reactivity was still maintained. Toxicity assessment of the degradation intermediates by ECOSAR and TEST showed that the electrode could effectively reduce the biotoxicity of OTC. In this study, the interface of the catalytic electrode was tuned to enhance its intrinsic activity, which provides an efficient strategy for electrocatalytic remediation of antibiotic contamination.