The role of hydrogen during Pt–Ga nanocatalyst formation

摘要: Hydrogen plays an essential role during the in situ assembly of tailored catalytic materials, and serves as key ingredient multifarious chemical reactions promoted by these catalysts. Despite intensive debate for several decades, existence nature hydrogen-involved mechanisms - such hydrogen-spillover, surface migration have not been unambiguously proven elucidated up to date. Here, Pt-Ga alloy formation is used a probe reaction study behavior atomic transport H Ga, starting from Pt nanoparticles on hydrotalcite-derived Mg(Ga)(Al)Ox supports. In XANES spectroscopy, time-resolved TAP kinetic experiments, HAADF-STEM imaging EDX mapping are combined Pt, Ga series H2 reduction experiments 650 °C. itself dissociates hydrogen, but dissociated hydrogen species do induce significant Ga(3+) cations support. Only presence partial into Ga(δ+) observed, suggesting that different dominate Pt- Mg(Ga)(Al)Ox-dissociated species. This made possible Pt-dissociated which spillover onto non-reducible Mg(Al)Ox or partially reducible undergo long-range over support surface. Moderately mobile Ga(δ+)Ox migrates towards clusters, where only fully reduced Ga(0) condition immediate stabilization inside alloyed nanoparticles.