Mechanism of Hydrogen Spillover on WO₃(001) and Formation of H_xWO₃ (x = 0.125, 0.25, 0.375, and 0.5)

Abstract

Hydrogen spillover onto the WO 3 (001) surface and further into the bulk in the presence of a platinum catalyst was investigated by density functional theory calculations. The diffusion pathways are designed based on the energetic preference of hydrogen adsorption. Atomic H migrates from a platinum catalyst, where it is adsorbed upon H 2 dissociative chemisorption, to terminal oxygen on WO 3 (001) surface, followed by migration to in-plane oxygen and then diffusion across the surface or insertion in the lattice. We first theoretically corroborated the role of water in facilitating the hydrogen spillover process. The otherwise prohibitively high activation barriers were considerably reduced with the participation of water, which agrees well with experimental facts. The high mobility of H inside the WO 3 lattice was also identified with low calculated diffusion barriers for several selected migration pathways. Finally, the effects of hydrogen concentration and electronic structures of H x WO 3 were investigated. This study unravels the formation mechanisms of H x WO 3 via spillover and sheds light on the microscopic surface and bulk processes.

Discoloration Effect and One-Step Synthesis of Hydrogen Tungsten and Molybdenum Bronze (HxMO3) using Liquid Metal at Room Temperature

“…The fact that H + ion insertion into WO 3 and diffusion throughout the lattice has low activation energy is because of the favorable H-bonding interactions available during the entire process, and the increasing intercalated H + ions into WO 3 increase electron density at the Fermi level and charge carriers. 15 Figure 5c–f display the electron DOS of H x WO 3 ( x = 0.125, 0.25, 0.375, and 0.5). Clearly, when the H + ions intercalate into the interstitial site, a local energy level resulting from H + emerges at the Fermi level.…”

Titania supported synergistic palladium single atoms and nanoparticles for room temperature ketone and aldehydes hydrogenation

“…Hydrogen spillover is a well-known phenomenon in catalysis [28][29][30] . The spillover H species are high-active to reduce Ti 4+ for preparing black TiO 2 31,32 , W 6+ for color switch for WO 3 33,34 , and so on. Similarly, they can migrate to the above-mentioned single-atom sites for hydrogenation to replace in-situ H 2 dissociation.…”

Effect of Tungsten Species on Selective Hydrogenolysis of Glycerol to 1,3‐Propanediol

“…Considering the selectivity for 1,3‐PDO on PtNPs‐HSiW/mAl 2 O 3 was better than that on the mixture of PtNPs/mAl 2 O 3 and HSiW, the bimetallic heterogeneous catalyst had superiority for the selective production of 1,3‐PDO during hydrogenolysis of glycerol. The authors also thought that the electronic donor‐acceptor interaction between the Pt 0 and W x + species was the possible reason for the high performance of PtNPs‐HSiW/mAl 2 O 3 catalyst [72,78,79] …”