Molybdenum compound cocatalyzed Ni-based anode electrocatalysts for EOR in alkaline media

Abstract

In this study, Mo2C and MoS2 were used as cocatalyst for a non-noble metal for the first time for ethanol electro-oxidation reaction (EOR) in alkaline media. Anode electrocatalysts containing Nickel, Mo compound, and carbon support were synthesized at different weight ratios of Ni and Mo2C (or MoS2) while keeping the carbon support weight constant in each catalyst combination to investigate the best weight ratio among our range. Physical characterizations of the electrocatalysts were investigated by XRD, XPS, SEM-EDS, EDAX, and TEM techniques. Electrochemical performance of the catalysts was studied via cyclic voltammetry (CV), linear sweep voltammetry (LSV), and chronoamperometry (CA) by using a home-made electrochemical cell test system exhibiting similar alkaline direct ethanol fuel cell (ADEFC) architecture by giving the opportunity of using an anion exchange membrane. All of the Ni-Mo2C/C and Ni-MoS2/C at different weight ratios were shown better performance than pristine Ni and Ni/C. The highest current density was measured with Ni-Mo2C/C-2 (11.4 mA cm(-2)) anode catalyst, which exhibits the highest electrochemical reaction rate. The diffusion coefficient of the catalysts was calculated by using the data from linear LSV. CA experiment results showed that the tolerance for catalytic poisoning and durability of Ni-Mo2C/C-2 was better among all the electrocatalysts. Highlights Literature survey showed that Mo2C and MoS2 are promising co-catalysts for EOR. However, there is a lack of study on the use of Mo2C or MoS2 as co-catalyst with a non-noble metal. Molybdenum compound containing transition metal-based anode electro-catalysts were synthesized for EOR in alkaline media. A home-made electrochemical cell is designed to make the system more similar to an ADEFC system. The results of the electrochemical characterizations are showed that the Mo compound addition increased the catalytic activity and stability.