Electrochemical splitting of methane in melts: Producing and tuning high-value carbon materials with controllable morphology.

[Display omitted] • Electrochemical splitting of CH 4 produces H 2 and allows adjustable carbon quality. • Hydrogen production is physically separated from carbon deposition in melts. • Electrode and kinetics can regulate the composition and structure of carbon products. • The C-Ni-50 mA exhibits CNT structure and good adsorption properties. • The C-Ag-50 mA exhibits open hollow carbon structure and good capacitive properties. Catalytic decomposition of methane offers a viable solution for producing pure hydrogen and nanocarbon without emitting carbon dioxide. However, conventional thermal catalytic processes and catalysts have limitations in terms of poor carbon quality and catalyst deactivation due to carbon deposition. The newly developed electrochemical splitting of methane (ESM) in molten salt has emerged as a promising alternative that allows for the separate production of hydrogen at the anode and carbon deposition at the cathode. In this study, hydrogen produced via ESM while generating nanocarbon with diverse structures through manipulations of the cathode material and kinetics. Carbon nanotubes grown on Ni cathode, possessing high specific surface area and abundant functional groups, displayed excellent adsorptive capacity for dye adsorption. The open hollow nanocarbon grown on the Ag cathode displayed good capacitance performance. ESM technology has immense potential to enhance the utilization value of carbon by-products and the commercial production of green hydrogen. [ABSTRACT FROM AUTHOR]