Etude des chaines metal-metal dans la structure type MnP: Les arseniure et phosphure “MoAs” et WP et leurs solutions solides avec les composes MX ()

Advancement of Platinum (Pt)-Free (Non-Pt Precious Metals) and/or Metal-Free (Non-Precious-Metals) Electrocatalysts in Energy Applications: A Review and Perspectives

“…The electron location function (ELF) in bulk WP, crystal structure of WP (with and without P), partial and total density of states for the bulk WP, and site view of possible exposed terminations (I, II) for the (101) surface are shown in Figure 29a, 29b, 29c, and 29d, respectively. The authors found W−W and W−P bond lengths in the range of 2.842−2.906 Å and 2.445−2.485 Å, respectively, which is consistent with experimental values, 463 and the electron location function (ELF) 464 was used to confirm the nature of the correlative bonds in the bulk WP that reflects the electronic "jelium", similar to that in the metallic system (see Figure 30a). The authors presented W atoms in the bulk WP without P in the 3D metallic framework (see Figure 30b).…”

Structural Characterization of Tungsten Phosphide (WP) Hydrotreating Catalysts by X-ray Absorption Spectroscopy and Nuclear Magnetic Resonance Spectroscopy

“…As an ab initio calculation, FEFF uses a list of atomic coordinates in a cluster and physical information about the system, such as type of absorbing atom and excited core-level for its calculation. In our case, the list of atomic coordinates was simplified using ATOMS which generates the required coordinates starting from a crystallographic description of the WP system taken from the work of Guérin et al The data were then analyzed using the FEFFIT program. In FEFFIT, the fitting model was expressed as a sum over all scattering geometries or simple paths j .…”

“…One amplitude factor A is fitted for the four W−P paths, and one is fitted for each W−W for each sample, giving a total of four parameters. The average coordination numbers of each shell N j is determined from this value and from the = 0.89 value obtained from WO 3 , being N j = d j A / , where d j is the theoretical degeneracy of the path obtained from the literature …”

“…Tungsten phosphide has the manganese phosphide (MnP) structure (strukturbericht designation B31, space group Pbnm ). The X-ray analysis was first reported by Schönberg and later refined by Guérin et al The structures of hexagonal WC (Figure a) and NiAs (Figure b) are related to that of WP (Figure c). All these structures are formed from different combinations of trigonal prisms, with the nonmetal atoms occupying interstitial positions within those prisms.…”

First-principles study of catalytic activity of W-doped cobalt phosphide toward the hydrogen evolution reaction

“…The structures of WP and CoP are similar. They were modeled using the data reported by Guerin, Sergent, and Prigent (ICSD #42056) [29], and the results are presented in Fig. 1(c).…”