A creative hydrothermal synthesis method followed by calcination for vanadium nitride (VN) is reported. The oxygen reduction reaction (ORR) study of the catalyst shows that VN possesses a comparable catalytic performance to commercial Pt/C catalyst. The ORR catalytic activity study of vanadium nitride, vanadium carbonitride, and vanadium carbide reveals that tuning anions offers a promising rou...

The reaction mechanism of methanol oxidation catalyzed by vanadium oxides on a silica support (V2O5/ SiO2) was investigated in a high-throughput operando reactor coupled with a Fourier transform-infrared (FT-IR) imaging system for rapid product analysis and six parallel, in situ Raman spectroscopy probes for catalyst characterization. Up to six V2O5/SiO2 catalysts with different vanadium loadin...

A new preparative route for vanadium phosphate catalysts is described using supercritical CO2 as an antisolvent. The amorphous microspheroidal VPO produced is shown to be more active than comparable crystalline VPO catalysts for the selective oxidation of n-butane to maleic anhydride and, furthermore, does not require an extensive pre-treatment or activation period to establish full catalytic a...

A series of bulk oxides (Sb2O3, Sb2O4, VSbO4, and V2O5) and alumina-supported oxides (Sb-O, V-O, and Sb-V-O) were synthesized by conventional methods. The resulting catalysts were characterized with XRD, BET, Raman, and CH3OH-temperature programmed surface reaction (TPSR) spectroscopy. XRD and Raman spectroscopy confirmed that the bulk oxides are present as crystalline phases and the alumina-su...

A series of supported V2O5/Al2O3 catalysts were synthesized by incipient wetness impregnation with vanadium isopropoxide in isopropanol solutions and subsequent calcination. The vanadium surface density was varied from 0.3 to 11.4 V atoms/nm2 spanning the sub-monolayer and above-monolayer regions. The resulting supported vanadium oxide catalysts were physically characterized with in situ Raman ...

A novel imido-modified SiO2-supported Ti/Mg Ziegler-Natta catalyst for ethylene and ethylene/1-hexene polymerization is investigated. The catalyst is prepared by modification of (SiO2/MgO/MgCl2)TiClx Ziegler-Natta catalysts via supporting vanadium species followed by reaction with p-tolyl isocyanate as imido agents, to get the merits from both the SiO2-supported imido vanadium catalyst and the ...

A series of V205/TiO 2/SiO 2 catalysts were structurally investigated by in situ Raman spectroscopy and chemically probed by methanol oxidation in order to determine the molecular structure-reactivity relationships of the V205/TiO 2/SiO 2 catalysts. Only surface TiO,. species are present on the 3% TiO 2 /S iO 2 catalysts, and the surface TiO x species as well as bulk TiO 2 (anatase) particles c...

The effect of the point of zero charge (PZC) of the support oxide (Al2O3,Nb2O5, SiO2 and ZrO2) on the molecular structure of hydrated vanadium oxide specieshas been investigated with EXAFS spectroscopy for low-loaded vanadium oxidecatalysts. It was found that the degree of clustering (i.e., the V---V coordinationnumber) and the V---V distance increase with decreasing PZC of ...

The oxidative dehydrogenation (ODH) of propane to propylene by supported vanadia catalysts has received much attention in recent years, but different reactivity trends have been reported for this catalytic reaction system. In the present investigation, the origin of these differing trends are investigated with synthesis of supported V/SiO2, V/TiO2, and V/Al2O3 catalysts prepared with three diff...

Vanadium-niobium oxide catalysts containing variable amounts of vanadium and prepared by coprecipitation were investigated using 51V solid-state NMR. It was found that, in samples containing less than about 8 mol % V2O5, vanadium occurs in three different oxygen environments: in isolated tetrahedra, in comer-sharing tetrahedra (pyrovanadate), and in distorted octahedra. The number of octahedral...