The energies of formation and mobilities of Cu surface species on Cu and ZnO in methanol and water gas shift atmospheres studied by DFT

Impact of the synthesis route of supported copper catalysts on the performance in the methanol synthesis reaction

“…In the latter, larger particles grow at the expense of smaller particles due to a net flux of metal-containing species from thermodynamically less stable smaller particles to more stable larger particles. Irrespective of the mechanism, particle growth is generally considered to depend on the reaction conditions [14], the metal-support interaction [15][16][17], the particle size (distribution) [18,19] and the interparticle spacing [20][21][22], and also on the geometry of the support [9,15,16,23,24]. It has for instance been shown that particle migration can be restricted by encagement or entrapment [23][24][25][26][27].…”

Kinetics of deactivation on Cu/ZnO/Al2O3 methanol synthesis catalysts

“…Rasmussen et al[31] provided an atomistic perspective on sintering in Cu/ZnO systems by DFT calculations. Concerning particle migration and coalescence, diffusion of Cu species on surfaces of Cu crystallites shifts the position of the center of mass of the crystallites, thus leading to crystallite migration.…”

Dynamic Imaging of Ostwald Ripening by Environmental Scanning Transmission Electron Microscopy

“…measured activity over a 50 hour period at 523 K and observed accelerated ageing on increasing the H 2 or CO partial pressures. By using Cu/ZnO, Kuechen and Hoffmann observed enhanced sintering of Cu particles with the presence of CO. Rasmussen et al . used DFT calculations to assess the stability and mobility of Cu‐x (where x is Cu, OH, CO, CH 3 O, HCOO) species on Cu particles and a ZnO support.…”

“…Previousw ork on the sintering of Cu in ag aseous environment has focused on the industrially relevant system of Cu/ ZnO/Al 2 O 3 .S un et al [28] measured activity over a5 0hour period at 523 Ka nd observed accelerated ageing on increasing the H 2 or CO partial pressures. By using Cu/ZnO, Kuechen and Hoffmann [29] observed enhanced sintering of Cu particles with the presence of CO. Rasmussen et al [30] used DFT calculations to assess the stability and mobility of Cu-x (where xi sC u, OH, CO, CH 3 O, HCOO) specieso nC up articles and aZ nO support. They investigated the stability of the various species at differ-ent temperatures and pressures, and then assessed the diffusion energy barriers in each case.…”