Phosphorus-Coordinated Pd@MXene Electrocatalyst for Efficient Electrocatalytic Hydrodechlorination of Diclofenac

In this study, we synthesized a phosphorus-coordinated Pd@MXene catalyst to address the drawbacks associated with high noble metal usage, susceptibility to poisoning, and stability issues in the electrocatalytic hydrodehalogenation (EHDC) of recalcitrant halogenated pollutants. The phosphorus-coordinated Pd@MXene exhibited an EHDC performance comparable to that of the benchmark electrode (Pd@MX/CC) when tested on the model pollutant diclofenac (DCF). Notably, the phosphorus-coordinated Pd electrode demonstrated an 80% reduction in Pd usage and a 3.9-fold increase in Pd utilization efficiency. This improved performance was consistent across a wide range of pH values (pH 3, 7, and 11) and was sustained over 10 reaction cycles for the removal of DCF. Furthermore, the enhanced catalytic activity of the phosphorus-coordinated Pd electrode was achieved in the EHDC of various halogenated compounds. Importantly, the electrode exhibited a favorable tolerance to inorganic ions during the EHDC process. Density functional theory (DFT) calculations provided insights into the electronic configuration regulation of phosphorus-coordinated Pd@MXene, optimizing binding energies for H* and dechlorinated intermediates. The reported promotion effect of halogenated pollutants degradation by the phosphorus-coordination approach offers new insights into efficient EHDC systems toward water purification.