Phase relations in the system V/Nb/O. V. Investigation of mixed crystals V 1-x Nb x O 2

Band Gap Tailored Zn(Nb1−xVx)2O6 Solid Solutions as Visible Light Photocatalysts

“…In addition, a weak pre-edge shoulder was observed in spectra of Nb 2 O 5 and ZnNb 2 O 6 containing Nb(V) atoms. This characteristic pre-edge is due to the dipole-forbidden electronic transition from 1s to 4d orbitals …”

“…This characteristic pre-edge is due to the dipoleforbidden electronic transition from 1s to 4d orbitals. 26 XANES spectra of Zn(Nb 1-x V x ) 2 O 6 solid solutions (x ) 0, 0.02, 0.04, 0.06, 0.08, 0.1) are shown in Figure 6b. All samples showed the characteristic pre-edges, indicating the oxidation state of Nb(V) in solid solutions.…”

Solid-State Synthesis of Niobium Carbide Electrocatalyst in the Presence of Vanadium as Suppressor of Energy Input and Greenhouse Gas Emission

“…When NbO 2 was reacted with VC at 1000 °C for 10 h, which is a sufficient time to completely consume VNbO 4 , NbO 2 remained (Figure S7), indicating that NbO 2 is not a necessary intermediate to yield NbC. Although NbO 2 is formed by the reduction of Nb 2 O 5 , VNbO 4 has V III and Nb V , whose valence states are included in VC , and identical to Nb 2 O 5 . The closer relationship between constituent ions prioritizes the formation of VNbO 4 over NbO 2 .…”

Rutile-type metal (Cr, V) niobates as catalysts for propane ammoxidation to nitriles: In situ characterization and operando reactivity

“…This is associated to their oxidation at the expense of lattice oxygen since the new Raman bands (270, 690, 774, 887, 987 cm À1 ) are characteristic of VNbO 4 [38]. Therefore, the reduction to V 3+ by coke oxidation is necessary for the generation of rutile-type VNbO 4 since VNbO 4 has vanadium only as V 3+ as demonstrated by XANES-measurements [43]. Further in situ Raman studies (not shown) demonstrated that no carbon deposits form if the precursors are treated in air; in this case the rutile-type compound did not form.…”