Atomically dispersed Pd electrocatalyst for efficient aqueous phase dechlorination reaction

High atom utilization is important for practical application of Pd catalysts in dechlorination of chlorinated organic pollutants (COPs). Herein, we report atomically dispersed Pd (coordinated with 2 pyridinic N) anchored on N-doped carbon (A-Pd-NC) as an efficient catalyst toward electrochemical dechlorination of COPs in aqueous solution. Constant current electrolysis showed that the A-Pd-NC catalyst possessed a much higher dechlorination activity (DA, 98.9 mmol•g⁻¹•h⁻¹) than commercial Pd/C (2.4 mmol•g⁻¹•h⁻¹). Using A-Pd-NC as an effective electrocatalyst, near 100% product selectivity of 4-chlorophenol to phenol could be achieved at pH = 3. Constant potential electrolysis, cyclic voltammetry (CV), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculation results suggested that the dechlorination stability of A-Pd-NC was dependent on the potential applied on the catalyst and the dechlorination reaction followed the hydrodechlorination mechanism with electrochemically adsorbed H as the reductant. © 2021 Elsevier Ltd.