THE UNIVERSITY OF TEXAS AT AUSTIN • COCKRELL SCHOOL OF ENGINEERING. DEPARTMENT OF CHEMICAL ENGINEERING

Seminar Abstract:

In the current talk we will present our recent results on the development of alternative catalysts for H₂ production.  The main objective of our research is to identify catalysts to substantially reduce or replace Platinum-group metals.  Our research approaches involve parallel efforts in density functional theory (DFT) calculations, surface science experiments on model systems, and synthesis and characterization of supported catalysts under thermochemical or electrochemical conditions.

We will first use water electrolysis to demonstrate the feasibility of using monolayer Pt on tungsten carbide (WC) to achieve the same activity as bulk Pt [1].  We will present DFT calculations of similar electronic and chemical properties between monolayer Pt/WC and Pt, synthesis and characterization of monolayer Pt/WC films, and electrochemical evaluation of the activity and stability of Pt/WC for water electrolysis.  Comparing to the leading Pt electrocatalyst, the monolayer Pt/WC represents a reduction by a factor of ten in Pt loading [2].  We will then use the thermochemical production of H₂ to illustrate the advantages of using bimetallic catalysts.  Bimetallic catalysts often show unique activity and selectivity over their parent metals due to the electronic modification and strain effect.  We will present our results of using Ni/Pt bimetallic surfaces and catalysts for H₂ production from polyols [3,4] and ammonia [5], further highlighting the importance of using the combined approaches of DFT calculations, surface science experiments, and reactor evaluations.

[1]  D.V. Esposito, S.T. Hunt, K.D. Dobson, B.E. McCandless, R.W. Birkmire and J.G. Chen, “Low-Cost Hydrogen Evolution Catalysts Based on Monolayer Platinum on Tungsten Monocarbide (WC) Substrates”, Angewandte Chemie International Edition, 49 (2010) 9859-9862

[2]  D.V. Esposito and J.G. Chen, “Monolayer Platinum Supported on Tungsten Carbides as Low-Cost Electrocatalysts: Opportunities and Limitations”, Energy & Environmental Science, 4 (2011) 3900-3912.

[3]  M. Salciccioli, W. Yu, M.A. Barteau, J.G. Chen, D.G. Vlachos, “Differentiation of O-H and C-H Bond Scission Mechanisms of Ethylene Glycol on Pt and Ni/Pt Using Theory and Isotopic Labeling Experiments”, Journal of the American Chemical Society, 133 (2011) 7996-8004.

[4]  W. Yu, M.A. Barteau and J.G. Chen, “Glycolaldehyde as a Probe Molecule for Biomass-derivatives: Reaction of C-OH and C=O Functional Groups on Monolayer Ni Surfaces”, Journal of the American Chemical Society, 133 (2011) 20528-20535.

[5]  D.A. Hansgen, D.G. Vlachos and J.G. Chen, “Using First Principles to Predict Bimetallic Catalysts for the Ammonia Decomposition Reaction”, Nature Chemistry, 2 (2010) 484-489.