Evaluation of the optical gap of TiO<sub>2</sub> Obtained by Pechini method:influence of the variation of the anatase-rutile phases

Araújo, Dagoberto dos Santos; Diniz, Verônica Cristina de Souza; Torquato, Ramon Alves; Costa, Ana Cristina Figueiredo de Melo

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Artigo • Matéria (Rio J.) 23 (1) • 2018 • https://doi.org/10.1590/S1517-707620170001.0285 copy

Evaluation of the optical gap of TiO₂ Obtained by Pechini method:influence of the variation of the anatase-rutile phases

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

In this work, TiO₂ was synthesized by the Pechini method in different proportions of citric acid/metal cations to evaluate the influence of the anatase and rutile phases on the structure, morphology and optical energy gap. Thus, the samples were characterized by XRD, FTIR, distribution and size of clusters, density by helium picnometry, TGA and determination of gap band from the diffuse reflectance. The results show the formation of the anatase and rutile phases in all proportions of citric acid/metal cations evaluated. Morphologically the samples had agglomerate size between 15,89 and 19,34 μm with density around 3.7 g/cm³. Regarding the optical properties evaluated, it was observed that the increase in the ratio of the rutile phase to the anatase phase did not significantly alter its band gap, obtaining values between 2,97 and 3,00 eV.

Key words:
nanoparticles; TiO₂; Pechini method; band gap

Amostras	Fases	Tamanho do Cristalito da fase principal (nm)	Cristalinidade (%)	Parâmetro de rede (Å)	GOF
1:1	Anatásio: 94,70%	22,7	82,6	a = 3,78, c = 9,50	1,16
1:1	Rutilo: 5,30%	22,7	82,6	a = 3,78, c = 9,50	1,16
2:1	Anatásio: 87,76%	21,3	82,0	a = 3,78, c = 9,50	1,32
2:1	Rutilo: 12,24%	21,3	82,0	a = 3,78, c = 9,50	1,32
3:1	Anatásio: 78,99%	22,7	82,6	a = 3,78, c = 9,50	1,14
3:1	Rutilo: 21,01%	22,7	82,6	a = 3,78, c = 9,50	1,14
4:1	Anatásio: 83,58%	22,8	83,9	a = 3,78, c = 9,50	1,27
4:1	Rutilo: 16,42%	22,8	83,9	a = 3,78, c = 9,50	1,27
5:1	Anatásio: 88,43	23,3	83,8	a = 3,78, c = 9,50	1,24
5:1	Rutilo: 11,57%	23,3	83,8	a = 3,78, c = 9,50	1,24

Amostras de TiO₂	D (10 %) (µm)	D (50 %) (µm)	D (90 %) (µm)
1:1	3,01	17,75 ± 0,598	39,60
2:1	3,71	18,16 ± 1,421	39,98
3:1	4,06	19,34 ± 0,606	40,42
4:1	3,14	15,89 ± 1,189	35,62
5:1	4,16	18,12 ± 0,875	38,36

TiO₂	1:1	2:1	3:1	4:1	5:1
Perdas de massas (%) – 1° Evento	6,52	22,60	7,07	2,24	3,49
Perdas de massas (%) – 2° Evento	–	–	–	4,49	1,81

Laboratório de Hidrogênio, Coppe - Universidade Federal do Rio de Janeiro, em cooperação com a Associação Brasileira do Hidrogênio, ABH2 Av. Moniz Aragão, 207, 21941-594, Rio de Janeiro, RJ, Brasil, Tel: +55 (21) 3938-8791 - Rio de Janeiro - RJ - Brazil
E-mail: revmateria@gmail.com

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[1] Autor Responsável: Dagoberto dos Santos Araújo

Relação molar	1:1	2:1	3:1	4:1	5:1
Densidade média (g/cm ³ )	3.7591	3.8210	3.7595	3.7465	3.7653

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Evaluation of the optical gap of TiO2 Obtained by Pechini method:influence of the variation of the anatase-rutile phases

ABSTRACT

Evaluation of the optical gap of TiO₂ Obtained by Pechini method:influence of the variation of the anatase-rutile phases