Mesoporous Tantalum Oxide Photocatalyst: Structure and Activity Evaluation

Abstract

International audienceMesoporous nanostructured pure tantalum pentoxide and Eu-doped Ta2O5 were produced by facile and reproducible one-pot procedure not involving structure directing agents. The as-produced material is poorly crystalline and catalytically inactive. Photoluminescence behavior of the doped oxide indicates that it is formed by quick nucleation of pure Ta2O5, leaving the Eu-dopant only on the surface of the formed material. Further thermal treatment leads to crystallization and structural transformation as revealed by in situ X-Ray Diffraction (XRD) and Rietveld refinement used to identify and quantify the emerging phases as well as Diffuse Reflectance UV-vis Spectroscopy (DR-UV-Vis) and Raman Spectroscopy studies. The thermally induced transformation results in generation of surface oxygen vacancies that provide the material with pronounced photocatalytic activity in selective oxidation of aromatic amine compounds. The processes of generation and curing of the vacancies have been followed and quantified by temperature programmed oxidation and reduction and photoluminescence studies, offering in depth insight into the reaction mechanism

Effect of Adsorbed Water Molecules on the Surface Acidity of Niobium and Tantalum Oxides Studied by MAS NMR

“…28-0317). − Figure b shows that Ta 2 O 5 · n H 2 O, Ta 2 O 5 -350 and Ta 2 O 5 -450 exhibit no diffraction peak, which belong to amorphous phase. The previous studies find that Ta 2 O 5 remains amorphous until around 600 °C and low-temperature β-Ta 2 O 5 is formed when amorphous Ta 2 O 5 is calcined at 700 °C. − …”

Stokes and Anti-Stokes Luminescent Rare-Earth-Doped Tantalum Oxide Nanoparticles

“…Meanwhile, the preparation of REE-doped particles of Ta 2 O 5 is presented in a small number of publications. 27−31 The obtained materials are promising for photocatalytic 26,29 and electrocatalytic 30 applications, rib waveguide lasers, 32 and X-ray-excited optical luminescent agents. 31 The applicability of luminescent−transparent tantalum oxide nanoparticles (NPs) to decorate upconversion nanophosphors NaYF 4 :Yb 3+ /Er 3+ /Tm 3+ @NaGdF 4 for in vivo multimodal imaging was shown by Xiao et al 33 Among the variety of REEs doped in Ta 2 O 5 (La, Ce, Eu, Tb, Er, Tm, and Yb), we chose Eu, Er, and Yb for several reasons.…”

“…On a Ta 2 O 5 base, luminescent thin films, − bulk gels, and mixed oxides were prepared. Meanwhile, the preparation of REE-doped particles of Ta 2 O 5 is presented in a small number of publications. − The obtained materials are promising for photocatalytic , and electrocatalytic applications, rib waveguide lasers, and X-ray-excited optical luminescent agents . The applicability of luminescent–transparent tantalum oxide nanoparticles (NPs) to decorate upconversion nanophosphors NaYF 4 :Yb 3+ /Er 3+ /Tm 3+ @NaGdF 4 for in vivo multimodal imaging was shown by Xiao et al…”

Expounded Photoelectric and Electrochemical Profiling of LRE3+:β‐Ta2O5 (Ln3+ = Ce3+, Pr3+, Nd3+) for High Performance in Energy Systems

“…Being a semiconductor material with the larger bandgap energy, i.e., E g = 3.8-5.3 eV, Ta 2 O 5 has often been tested for its photocatalysis. [4] However, its practical employment is limited in the commercial sense due to its potential of absorbing only UV light (Table 1). Nevertheless, it has excellent electrical and electrochemical performance.…”