Kinetic study and simulation of molybdenum borides for hydrogen evolution reaction

Harunal Rejan, Ramji and Muhammad Qhaliff, Zainal Ibidin and Nicolas, Glandut and Joseph, Absi and Lim, Soh Fong (2024) Kinetic study and simulation of molybdenum borides for hydrogen evolution reaction. International Journal of Advances in Applied Sciences (IJAAS), 13 (3). pp. 698-706. ISSN 2252-8814

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Abstract

This paper presented the kinetic study of molybdenum borides via the Volmer-Heyrovsky-Tafel (V-H-T) mechanistic steps for hydrogen evolution reaction (HER). A theoretical approach was carried out to investigate the kinetic properties of several molybdenum boride materials for HER in 0.5 M H2SO4. Our findings offer definitive proof that the simulated results show that B, Mo, Mo2B, and α-MoB, proceed through V-H mechanistic steps (slower kinetics) while β-MoB and MoB2 exhibit V-H-T mechanistic steps with higher kinetics. The kinetic parameters were determined in terms of the standard rate constant parameters for the Volmer step (kV, k-V), Heyrovsky step (kH, k-H), and rate constant for the Tafel step (kT, k-T). The simulation was able to predict the overpotential at 10 mA/cm2, η10 recorded at approximately 780, 585, 480, 350, 310, and 300 mV for B, Mo, Mo2B, αMoB, β-MoB, and MoB2 respectively. Based on these findings, the adopted mathematical model shows good coherency to the experimental findings. The simulation work provides a good numerical estimation of the characteristics of the electrocatalyst for HER. This paper successfully elucidated the reaction mechanisms (V-H-T steps) and understood the ratelimiting steps involved in the HER process on Mo-B materials.

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