Hydrogen Generation from Formic Acid
Department of Chemistry,
The University of Hong Kong
Experiments are proposed to develop an efficient catalyst for selective decomposition of formic acid to generate hydrogen at low temperature. Materials optimization at the atomic, nanoscopic and large length scales will be sought by various synthetic attempts and advanced characterizations. Experiments will be performed to detect reaction intermediates, quantify isotope kinetic affects to help elucidate the reaction mechanism which has an undesirable alternative pathway of forming carbon monoxide and water. The project is built on preliminary results which show high activity and selectivity of a platinum-ruthenium based catalyst.
Room temperature generation of hydrogen from a relatively safe liquid fuel
is attractive for small fuel cells powering portable electronic devices. Formic
acid decomposition also plays a central role in low temperature aqueous phase
water-gas shift reaction for the generation of hydrogen from carbon monoxide
and water. The success of a low temperature water-gas shift reaction can help
clean coal gasification, generation of hydrogen as a clean fuel, and better
carbon capturing. These are the latest foci of clean energy research for better
environment.
Fig. 1: (a) GC spectrum of a calibration gas mixture containing hydrogen, air, carbon monoxide, methane, and carbon dioxide. (b) GC spectrum of the product gas from formic acid decomposition showing only hydrogen, carbon dioxide, and air. The air was present initially above the formic acid reactor. The TCD detected H2/CO2 peak area ratio is small than their concentration ratio due to their relative thermal conductivity.
Fig. 2: Set up to determine formic acid decomposition rates and product compositions. (Inert gas can be introduced to assist a steady flow when decomposition rate is low. An additional gas chrommatogram can be used to determine effectiveness of products separation by gravity.)
Fig. 3: Transmission electron microscopy images of high surface area high porosity mesoporous carbon synthesized from three kinds of mesoporous silicas. Scale bar is 50 nm in all figures.
Fig 4: HRTEM image of Pt-Ru nanoparticles supported in mesoporous carbon. The scale bar is 5 nanometers.
Video 1: Dehydrogenation of formic acid to give only hydrogen and carbon dioxide using the catalyst developed.
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Video 2: The hydrogen generated through the use of this catalyst is able to power a small fan when fed to a hydrogen-air fuel cell made also by our group.
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[2] S.W. Ting, S.A. Cheng, K.Y. Tsang, N. van der Laak, and K.Y. Chan, "Low Activation Energy Dehydrogenation of Aqueous Formic Acid on Platinum-Ruthenium-Bismuth Oxide at Near-Ambient Temperature and Pressure", Chem. Comm.,web published 22 October 2009, DOI:10.1039/b916507j.
[1] K. Y. Chan, X. Zhang, C. M. Lam, A.C.C. Tseung, P.K. Shen, and J.K. You, “Methods and Apparatus for the Oxidation of Glucose Molecules”, US Patent 7,419,580 issued September 2008.