In situ muSR and NMR investigation of methanol dissociation on carbon-supported nanoscaled Pt-Ru catalyst

In situ muSR and nuclear magnetic resonance (NMR) experiments on the investigation of methanol decomposition on Pt-Ru nanoscaled catalyst supported on Vulcan XC-72 carbon black (Pt-Ru/Vulcan XC-72) are presented. Avoided-level-crossing muon spin resonance measurements reveal the resonance line at magnetic field 2.018 T, we assign to transient CH₂?OMu? formaldehyde muonated radical. Results obtained allow us to estimate the contribution of chemical decomposition reaction process for the formaldehyde—carbon oxide—hydrogen conversion on Pt-Ru/Vulcan XC-72 catalytic material. NMR spectrum of the methanol covered Pt-Ru/Vulcan XC-72 consists of three broad resonance lines. Two of them are assigned to OH and CH₃ groups of methanol bound to the carbon black surface. Following the existing literature, which indicates that polymerization of formaldehyde readily takes place when the monomer is adsorbed on some active surface, the third one is assigned to the resonance signal of oligomeric species of formaldehyde. Taking into account the results of our experiments on electrochemical hydrogenation of carbon nanotubes, we do not exclude that the hydrogen arising as a result of methanol decomposition would also contribute to this signal. The high surface area of amorphous carbon nanoparticles of Vulcan XC-72 is favourable to adsorb the hydrogen on their surface.