Synergistic integration of Ni and β-Mo2C in carbonized wood substrates for highly efficient water splitting and dye adsorption applications

Abstract

The present work effectively achieved the production of a self-supporting electrode with high efficiency. The process involves incorporating nickel and molybdenum carbide (Mo2C) phases within the channels of wood through high-temperature calcination at the nanoscale. The obtained carbonized wood (CW) possesses low tortuosity and three-dimensional vertical channels, providing an excellent substrate for the preparation of Ni-Mo2C/N-CW electrodes. Mo2C is well known for its considerable potential as a non-precious metal electrocatalyst with enhanced catalytic activity. The successful doping of nickel and nitrogen into molybdenum carbide not only promotes the formation of β-Mo2C, but also improves the electron transfer rate and mass diffusion pathway. Consequently, the Ni-Mo2C/N-CW electrode exhibits excellent performance in the hydrogen and oxygen evolution reactions (HER and OER, respectively). Only voltages of 89 and 253 mV are required to achieve a current density of 10 mA cm−2, respectively. When the Ni-Mo2C/N-CW catalyst is used as both cathode and anode during hydrolysis, current densities of 10 and 100 mA cm−2 can be achieved with excellent durability and stability at voltages of 1.56 and 1.72 V, respectively. The distinctive porous structure of the wood substrate is of crucial importance for promoting the adsorption and dissociation of water molecules, enhancing the catalytic performance. In addition, the present material exhibits advantageous characteristics, including a high specific surface area and a significant number of adsorption sites, making it a very promising candidate for applications involving the adsorption of dyes, such as rhodamine B (RhB).