A CuNi bimetallic cathode with nanostructured copper array for enhanced hydrodechlorination of trichloroethylene (TCE)

Highlights: • A CuNi bimetallic cathode was prepared by electrodeposition for TCE dechlorination. • The Ni substrate was coated with regularly distributed fold shape copper array. • TCE removal was up to 99.7 ± 0.1% at 20 mA cm⁻² in 90 min. • The normalized energy consumption decreased with the increasing current density. • The cathode can be used for TCE removal from contaminated water of low conductivity. To address the challenges of low hydrodechlorination efficiency by non-noble metals, a CuNi bimetallic cathode with nanostructured copper array film was fabricated for effective electrochemical dechlorination of trichloroethylene (TCE) in aqueous solution. The CuNi bimetallic cathodes were prepared by a simple one-step electrodeposition of copper onto the Ni foam substrate, with various electrodeposition time of 5/10/15/20 min. The optimum electrodeposition time was 10 min when copper was coated as a uniform nanosheet array on the nickel foam substrate surface. This cathode exhibited the highest TCE removal, which was twice higher compared to that of the nickel foam cathode. At the same passed charge of 1080C, TCE removal increased from 33.9 ± 3.3% to 99.7 ± 0.1% with the increasing operation current from 5 to 20 mA cm⁻², while the normalized energy consumption decreased from 15.1 ± 1.0 to 2.6 ± 0.01 kWh log⁻¹ m⁻³. The decreased normalized energy consumption at a higher current density was due to the much higher removal efficiency at a higher current. These results suggest that CuNi cathodes prepared by simple electrodeposition method represent a promising and cost-effective approach for enhanced electrochemical dechlorination.