Methyl crotonate hydrogenation over Pt: Effects of support and metal dispersion

• Methyl crotonate hydrogenation over Pt displays self-inhibition effects.
• Higher Pt dispersion has greater resistance to inhibition by methyl crotonate.
• Kinetic behavior of H2 dissociation can be tuned by Pt dispersion.
• Al2O3 support improves resistance to inhibition on Pt surface.
• TiO2 support intensifies inhibition effects.

Gas-phase hydrogenation of methyl crotonate (MC) has been studied over Pt supported on Al2O3, C, SiO2, and TiO2. The physicochemical properties of the catalysts were characterized by use of N2 physisorption, transmission electron microscopy and CO chemisorption. The effects of Pt dispersion and nature of the support on the catalytic properties of the catalysts were determined by measurements of the kinetic parameters for MC hydrogenation. The results clearly display MC inhibition effects on the hydrogenation over the catalysts. However, the degree of MC-inhibition is found to depend on both the Pt dispersion and the support used. For alumina a high Pt dispersion can promote the resistance of the catalyst against MC-inhibition, and even allow hydrogen adsorption to become equilibrated on the Pt surface. Compared to SiO2 and C supports, Al2O3 improves the resistance of the Pt surface against MC inhibition, whereas TiO2 reduces the resistance. Possible reasons are suggested to understand the positive effect of Al2O3 on Pt against MC inhibition.

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