Activating palladium nanoparticles via a Mott-Schottky heterojunction in electrocatalytic hydrodechlorination...

This work exploited one novel power of the Mott-Schottky heterojunction interface in activating the palladium (Pd) in electrocatalytic hydrodechlorination reaction (EHDC, one reaction targeted for the abatement of chlorinated organic pollutants from water). By forming a Mott-Schottky contact with polymer carbon nitride (Pd-PCN), the Pd nanoparticles enable a relatively complete and pseudo-first-order conversion of 2,4-dichlorophenol (2,4-DCP) to phenol and Cl^- with the reaction rate constant (k_obs) triple that of the conventional Pd-C (0.68 vs. 0.26 min^-1 mol_Pd^-1). Further comparison in k_obs of Pd-PCN and the Pd catalysts reported in literatures revealed that our Pd-PCN was among the top active catalysts for EHDC. The robust performance of Pd-PCN was attributed to the strong metal-support interactions at the Mott-Schottky heterojunction interface, which enriched the electron on Pd and improved its anti-poisoning ability against phenol. The strong support-metal interactions also endowed Pd-PCN with high activity/structure stability in EHDC. The presence of some anions in water body including NO₃^-, NO₂^- and Cl^- exerted little effect on EHDC, while the reduced sulfur compounds (S^2- and SO₃^2-), even in a very low concentration (1 mM), could significantly deactivate the catalyst. This work provides a facile and efficient strategy to activate noble metals in catalytic reactions.