The widespread discharge of halogenated organic pollutants (HOPs) in wastewater brings significant risks to the environment and human health due to potent high toxicity, antibacterial activity, and strong biodegradation resistance. Adsorbed atomic hydrogen (H* ads )-mediated electrocatalytic hydrodehalogenation (EHDH) has been recognized as an efficient strategy for HOPs removal through selectively breaking carbon-halogen bonds. In this work atomic Pd uniformly anchored on molybdenum disulfide (denoted as Pd-MoS 2 ) was synthesized through a facile hydrothermal method and found with state-of-the-art specific activity in florfenicol (FLO) removal via the H* ads -mediated EHDH process. Pd-MoS 2 completely dehalogenated (∼100 %) FLO within 30 min at a rate constant of 0.15 min −1 , which was 6.0, 6.5 and 33.1 times the value of MoS 2 , Pd/C and carbon paper samples, respectively. Notably, the toxicity of the wastewater was reduced to 1/6 of its original value after the treatment. Moreover, Pd-MoS 2 presented superior catalytic stability in five successive cycles. Furthermore, Pd-MoS 2 was also robust in complex water environment with practical applicability for industrial wastewater treatment. A dual-active-center mechanism with enhanced H* ads production capacity and the improved H* ads utilization efficiency was contributed to the increased EHDH activity on Pd-MoS 2 .
Zhiqiao He,Yiwen Tong,Sulin Ni,Xincheng Ye,Chengetai Portia Makwarimba,Xinwen Huang,Shihan Zhang,Shuang Song
Pd was electro-deposited on Ni foam using nitrogen-doped carbon as an inter-layer (EDPd/CNx/Ni). The as-prepared material was employed as the cathode for the electrochemical dechlorination of 3,6-dichloropicolinic acid (3,6-D) in an aqueous solution. When compared to the electrodes that direct the electrodeposition or chemical deposition of Pd on Ni foam, EDPd/CNx/Ni exhibited higher activity and selectivity during the electrocatalytic hydrogenation of 3,6-D to form the intermediates 3-chloropicolinic acid and 6-chloropicolinic acid, as well as the final product, 2-picolinic acid. Furthermore, the modified electrode maintained its high dechlorinating activity after continuous operation for three batches. On the basis of physical-chemical characterization and electrochemical measurements, it is proposed that the superior performance of the EDPd/CNx/Ni electrode benefits sufficiently from the accelerated generation of adsorbed hydrogen ([H] ads ). The electrodeposition method facilitates the generation of Pd with a higher percentage of exposed {111} facets. The CNx functions as an efficient support for the enlargement of the electrochemically active surface area, the reduction of Pd particle size, and improvement of the Pd dispersion. Moreover, CNx may also act as an electrocatalyst for the water-splitting reaction and favors the stabilization of chemisorbed active hydrogen.
Xiongqin Liu,Xuanrui Liu,Jun Zhao,Mingruo Ban,Shutao Wu,Fei Liu
The electrochemical reduction of furfural (FF) offers a sustainable approach for producing value-added furfural alcohol (FA). Nevertheless, the limited adsorbed hydrogen (*H) generation capacity on Cu cathode restricts the reaction performance. Because the competitive adsorption of FF and *H decreases *H coverage and induces severe dimerization, most prior studies employed low FF concentrations (typically 20 mM) under constant potential conditions. In this work, carbon-supported Cu nanoparticles grown on Cu nanowire arrays (defined as Cu@Cu/C) were combined with constant current electrolysis for high-concentration FF reduction. A high Faradaic efficiency (72.9 %) and production rate (0.14 mmol cm −2 h −1 ) of FA were realized at −10 mA cm −2 , with a conversion of 98.1 %. Both the Faradaic efficiency and production rate can be sustained with gradual increases in current density or adjustments of FF concentration within a certain range, showing substantial enhancement relative to Cu-nano. Compared with pure Cu-nano, the favorable interaction between Cu nanoparticles and carbon support was certified to regulate the adsorption configuration and strength of FF, and enhance the *H generation performance, which optimizes the *H coverage at cathodic surface and promotes FF hydrogenation with *H via an electrocatalytic hydrogenation (ECH) mechanism. Overall, this work provides a simple and feasible strategy to promote interfacial *H, thus enhancing higher concentration hydrogenation of FF to FA by constant current electrolysis over Cu-based cathode.
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