(676g) Trends in Methanol Decomposition over Supported Metal Catalysts

Methanol decomposition stands as an attractive chemistry given the possibility of using methanol as a source of hydrogen. Methanol at temperatures over 200 ºC and partial pressures over 10 kPa (in the presence of a metal catalyst) decomposes to carbon monoxide and hydrogen. We also see the hydrogenation of CO to CH₄ as well as the water-gas shift reaction (Figure 1) at these conditions. Through experimental and computational techniques, decomposition kinetics have been widely studied across different catalytic systems. However, the trend in this chemistry over the different supported catalysts is not documented from an experimental point of view. Our study aims to comprehensively investigate methanol decomposition over silica-supported metal catalysts. Some of the catalysts we investigate include Platinum, Palladium, Ruthenium, Copper, and Iridium supported on silica. We fabricate the Silica supported catalysts by using incipient wetness impregnation methods by using salts of metals. We use Transmission Electron Microscopy (TEM) to characterize the nanoparticle size of these formulated catalysts. This gives us the dispersion of the synthesized catalysts which helps us quantify the catalytically active sites. To quantitatively judge the trends for methanol decomposition, we plot the initial rates for the formation of carbon monoxide against the binding energies of carbon and oxygen over different catalysts to get a volcano plot. We compare these values to those reported in computational literature. The investigation serves as an experimental benchmark for further explorations of methanol decompositions over different catalytic systems.