(621bh) Transition Metal Nitrides As Promising Electro-Catalysts for Hydrogen Evolution Reaction

Today’s society is in pursuit of an alternative route for production of energy and chemicals due to scarcity of natural gases and fossil fuels. At the same time, strict environmental regulations push international scientific and industrial community towards more sustainable ways to meet the increasing demands of our energy-intensive society resulted in development of energy conversion technologies. As of now, hydrogen is accepted as an integral ingredient for renewably synthesis of e.g. ammonia and methanol. It is also the cleanest fuel and one of the most promising sources of energy [1]. The electrochemical hydrogen evolution reaction (HER) is a very interesting CO₂-free approach effectively catalyzed by the Pt group metals. But Pt is scarce and therefore expensive. In order to meet the increasing need for hydrogen and energy, new catalysts should be explored that are active for HER as good as or nearing that of Pt fulfills. If that achieves, precious Pt can be replaced by cheaper and more abundant material holding great promise for clean energy technologies.

In this study, we used density functional theory calculations to screen for highly stable and active catalysts amongst 104 transition metal nitride surfaces [2]. The free energy of all intermediates was calculated with density functional theory (DFT). For the candidates promising for HER, activation energies for H₂ formation were calculated at varying applied potentials [3]. The results nominate a few nitrides capable of catalyzing HER at low overpotentials of -0.1 to -0.35 V vs. SHE. We are currently examining these extremely promising HER catalysts experimentally and the preliminary observations and measurements are indicative of the validity of our model as the proposed overpotentials for HER agree with the experimental measurements.

References

1) Crabtree, G. W., Dresselhaus, M. S. and Buchanan, M. V. Phys. Today, 2004, 57, 39−44

2) Y. Abghoui, A. L. Garden, V. F. Hlynsson, S. Björgvinsdóttir, H. Ólafsdóttir, and E. Skúlason, Phys. Chem. Chem. Phys., 2015, 17, 4909–4918.

3) Y. Abghoui and E. Skúlason, in preparation (2015)