Observing single-site catalysis during reaction
Dr Simon Kondrat
Single-site heterogenous catalysis, where single metal sites are anchored onto a support structure, is a growing research area. Improved characterisation techniques have demonstrated the presence of such species in a range of novel and established catalysts. An area less well studied is the monitoring and evolution of such species during a catalytic reaction using in situ/operando techniques. Here we report a in situ/operando X-ray absorption spectroscopy study of single-site AuClx supported on carbon as a catalyst during the acetylene hydrochlorination reaction. Retention of single site species during reaction, without any observable Au nanoparticles, was observed. An induction period seen during the reaction was correlated with a change in Au oxidation state, indicating the importance of Au(I) in the catalytic cycle. Finally, the deactivation of the catalyst was studied and found to coincide with loss of single site AuClx species and formation of metallic Au. Evidence of strong acetylene-Au interactions were also observed.