In recent years’ molybdenum-based materials have been considered as alternative catalysts to noble metals, such as platinum, for the hydrogen evolution reaction (HER) [1, 2]. We have synthesized bulk binary metal borides (Mo₂B, MoB and MoB₂) by arc-melting as well as MoB and MoB₂ at the nanoscale by solid-state reaction and study their electrocatalytic activity towards HER in acid conditions for the first time. Among all the binary molybdenum borides, MoB₂ shows excellent HER activity in both micro- and nanoscale. However, the nanoscale MoB₂ shows a lower onset overpotential of about 150 mV compared to microscale MoB₂ under same conditions. The electrochemical studies clearly indicating that the HER activity was greatly dependent on their crystallographic structures (boron-dependency) as well as particle size [2]. Also, our recent density functional theory (DFT) calculations on MoB₂ suggest that boron is playing a prominent role in the catalytic activity of this compound. Detailed synthetic procedures, electrochemical properties and DFT calculations for these binary molybdenum borides will be discussed.

References:

1. J. Guo, J. Wang, Z. Wu, W. Lei, J. Zhu, K. Xia and D. Wang, J. Mater. Chem. A 5 (2017) 4879-4885.
2. Seh et al., Science 355 (2017) https://doi.org/10.1126/science.aad4998.
3. H. Park, A. Encinas, J. P. Scheifers, Y. Zhang and B. P. T. Fokwa, Angew. Chem. Int. Ed. 56 (2017), https://doi.org/10.1002/anie.201611756.