Effect of tungsten doping on catalytic properties of niobium oxide

Abstract

Um novo material à base de nióbia (Nb 2 O 5 ) foi sintetizado e quimicamente modificado para oxidar compostos orgânicos em meio aquoso, na presença de H 2 O 2 . A nióbia foi modificada por dopagem com tungstênio e também tratamento com H 2 O 2 com o intuito de potencializar suas propriedades oxidativas. A investigação dos produtos gerados pela oxidação do azul de metileno, usando a técnica de espectroscopia de massas com ionização por eletrospray (ESI-MS), mostrou que o corante foi sucessivamente oxidado produzindo diferentes compostos intermediários. A sucessiva hidroxilação durante o processo oxidativo indica a alta reatividade dos radicais hidroxilas que são gerados, envolvendo H 2 O 2 sobre a superfície do grão de nióbia dopada com W. Estes resultados sugerem fortemente que o H 2 O 2 pode regenerar in situ o grupo peróxido, permanecendo ativo no sistema.A novel material based on niobia (Nb 2 O 5 ) was synthesized to oxidize an organic compound in aqueous medium in the presence of H 2 O 2 after chemical modifications. Niobia was modified by doping with tungsten and also treating with H 2 O 2 in order to maximize the oxidative properties of this oxide. The analysis of the products from methylene blue dye oxidation with electrospray ionization mass spectrometry (ESI-MS) showed that the dye was successively oxidized to different intermediate compounds. The successive hydroxylation during this oxidation strongly suggests that highly reactive hydroxyl radicals are generated involving H 2 O 2 on the W-doped niobia grain surface. These results strongly suggest that the H 2 O 2 can regenerate in situ the peroxo group remaining active the system.

Graphitic Carbon Nitride Impregnated Niobium oxide (g-C3N4/Nb2O5) Type (II) Heterojunctions and its Synergetic Solar-Driven Hydrogen Generation

“…Figure shows the FTIR spectra of the as-synthesized pristine Nb 2 O 5 NPs and g-C 3 N 4 /Nb 2 O 5 heterostructure. The Nb 2 O 5 NPs spectral peaks (black line) are in good agreement with the available literature. , The bands located at 593, 870, 1376 cm –1 originated due to Nb–O stretching vibrations, respectively, while band at 788 cm –1 is attributed to Nb–O–Nb bending vibration. The band observed at 1629 cm –1 is due to the adsorbed bending vibrations of moisture, while the broadband at 3415 cm –1 are due to the stretching vibration of the hydroxyl groups.…”

CuO Decoration Controls Nb2O5 Photocatalyst Selectivity in CO2 Reduction

“…Our research group recently demonstrated that pristine Nb 2 O 5 has potential for CO 2 photoreduction, but with preferential CO evolution. Despite CH 4 being observed under specific synthesis conditions, its yields remain low, indicating that the interaction of CO 2 with Nb 2 O 5 surfaces is limited by its high acidity. − Decorating the catalyst with other semiconductors may increase the interaction of reduction intermediates, modifying its selectivity. CuO is a viable choice because of its well-known ability to reduce CO 2 to CH 4 .…”

Use of poly(3‐hydroxybutyrate)/niobium oxyhydroxide nanocomposites in photocatalysis: Effect of preparation methods

“…The ability of niobium oxyhydroxide to catalyze the process of removal of methylene blue from aqueous media has been demonstrated in previous works . Niobium‐based PHB/oxyhydroxide nanocomposites (S 2 ) prepared by different methods have been employed in the photocatalytic process to remove methylene blue dye from solution.…”