The conventional Pt/C material is the most important catalyst for the hydrogen evolution reaction. Recent experiments showed that jagged Pt nanowires have higher activities than Pt/C, and that their activity can be further improved by Ni(OH)2 decoration. We built up several models that simulate the surfaces of the two materials and performed density functional theory calculations of the hydrogen chemisorption energies. The superior activities of these materials can be explained by using the classic volcano curve [1] that describes the relations between the rate of hydrogen evolution and the hydrogen chemisorption energy. We have evaluated realistic high coverage situations for these models. Several sites on the model surfaces show a weaker adsorption energy for hydrogen, and are hence more active for HER, leading to the optimum position on the volcano. The activity of Pt for HER can hence be tuned and improved both by reaching sites with higher generalized coordination (not lower) and by electronic modification from doping by Ni in basic conditions.
[1] J. K. Nørskov, T. Bligaard, A. Logadottir, J. R. Kitchin, J. G. Chen, S. Pandelov, and U. Stimmingc "Trends in the Exchange Current for Hydrogen Evolution" J. Electrochem. Soc. (2005) 152, J23.
See more of this Session: Catalytic Hydrogen Generation II: Shift and Splitting Reactions
See more of this Group/Topical: Catalysis and Reaction Engineering Division
See more of this Group/Topical: Catalysis and Reaction Engineering Division