Effect of Er3+ ions on the phase formation and properties of In2O3nanostructures crystallized upon microwave heating

Abstract

A B S T R A C TRegular sized nanostructures of indium oxide (In 2 O 3 ) were homogeneously grown using a facile route, i.e. a microwave-hydrothermal method combined with rapid thermal treatment in a microwave oven. The presence of Er 3+ doping plays an important role in controlling the formation of cubic (bcc) and rhombohedral (rh) In 2 O 3 phases. The samples presented broad photoluminescent emission bands in the green-orange region, which were attributed to the recombination of electrons at oxygen vacancies. The photocatalytic activities of pure bcc-In 2 O 3 and a bcc-rh-In 2 O 3 mixture towards the UVA degradation of methylene blue (MB) were also evaluated. The results showed that Er +3 doped In 2 O 3 exhibited the highest photocatalytic activity with a photonic efficiency three times higher than the pure oxide. The improved performance was attributed to the higher surface area, the greater concentration of electron traps due the presence of the dopant and the possible formation of heterojunctions between the cubic and rhombohedral phases.

Realizing High Photocatalytic Performance of NaBiS2 Nanopowders via the Introduction of Rare‐Earth Elements

“…The midgap can increase the utilization of photons with a long wavelength and low energy to further improve the degradation ratio. In addition to the above analysis, Sm 3+ has an unfilled 4f shell and the reduction of Sm 3+ is thermodynamically feasible just like Eu 3+ and Er 3+ ions . All of these make it possible for electrons to be trapped on the surface of catalysts by Sm 3+ .…”

“…Furthermore, the introduction of rare‐earth (RE) ions can serve as electron traps to capture the photoexited electrons to increase the transfer efficiency of photoinduced carriers. In addition, it is possible that a new impurity energy level could be induced by RE ions, which will promote the absorption of light, with the extra photocarriers improving the catalytic activity …”

Indium Oxides and Related Indium‐based Photocatalysts for Water Treatment: Materials Studied, Photocatalytic Performance, and Special Highlights

“…Erbium was doped into In 2 O 3 at 4 mol% relative to In by Lemos et al, [ 119 ] which affected the In 2 O 3 phase transformations and the photocatalytic activity. The presence of Er 3+ doping was said to have played an important role in stabilizing the rhombohedral In 2 O 3 phase, resulting in a body‐centred cubic (bcc)–rh–In 2 O 3 mixture.…”

Investigação teórico-experimental do efeito da dopagem nas propriedades estruturais e eletrônicas do óxido de índio

“…A interação eletrônica com elementos constituintes do catalisador é dependente do caráter ácido base da superfície do óxido (YANG; HETTERSCHEID, 2020). A dopagem com íons La 3+ leva a um processo de quebra de simetria (LEMOS et al, 2017;LIMA et al, 2008), induzindo à formação de uma maior quantidade de defeitos, como por exemplo vacâncias de oxigênio, tais defeitos podem levar à criação de excesso de elétrons, gerando mudanças significativas na reatividade de superfície do óxido, afetando assim, a cinética da reação de evolução de oxigênio, uma vez que essa é intrisicamente dominada pela quimissorção das moléculas precursoras (H2O, OH − ) e da energia de ligação da superfície com os intermediários de reação (HUANG et al, 2019;HETTERSCHEID, 2020). A diferença nas energias de ligação a respeito dos intermediários de reação não são independentes, estão relacionados entre si pelos chamados relacionamentos de escala, sendo dependentes das propriedades de adsorção vinculadas às características eletrônicas e estruturais do catalisador (KOPER, 2013).…”