Search for: All records

Recently, stable non-oxidative conversion of methane (NOCM) for up to 8 h with a C 2 selectivity greater than 90% has been reported over Pt–Bi/ZSM-5 at moderate temperatures (600–700 °C). In this study, we show that the structure of the bimetallic nanoparticles on Pt–Bi/ZSM-5 catalyst is similar to Pt–Bi/SiO 2 . EXAFS indicates the formation of Pt-rich bimetallic Pt–Bi nanoparticles with Pt–Bi bond distance of 2.80 Å. The XRD spectra (on SiO 2 ) are consistent with cubic, intermetallic surface Pt 3 Bi phase on a Pt core. The Pt 3 Bi structure is not known in the thermodynamic phase diagram. In all catalysts, only a small fraction of Bi alloys with Pt. At high Bi loadings, excess Bi reduces at high temperature, covering the catalytic surface leading to a loss in activity. At lower Bi loadings with little excess Bi, the Pt 3 Bi surface is effective for non-oxidative coupling of CH 4 (on ZSM-5) and propane dehydrogenation (on SiO 2 ).