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The Polymerization Effect on Synthesis and Visible-Light Photocatalytic Properties of Low-Temperature β-BiNbO4 Using Nb-Citrate Precursor.

Zhai H, Kong J, Wang A, Li H, Zhang T, Li A, Wu D - Nanoscale Res Lett (2015)

Bottom Line: The polymerization effect is beneficial to lower the phase formation temperature and obtain smaller particle catalysts.The Low-β BiNbO4 powder prepared by citrate method shows better degradation rate of about 1 h to decompose 80 % of MV and also displays good photocatalytic stability.The better photocatalytic performance of BiNbO4 powders prepared by citrate method can be attributed to its smaller band gap and better crystallinity.

View Article: PubMed Central - PubMed

Affiliation: Henan Key Laboratory of Photovoltaic Materials, College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, 453007, People's Republic of China. haifazhai@126.com.

ABSTRACT
Low-temperature β-BiNbO4 powders (denoted as Low-β) were prepared by citrate and Pechini methods using homemade water-soluble niobium precursors. The addition of ethylene glycol and the resultant polymerization effect on the synthesis and visible-light photocatalytic performance of β-BiNbO4 powders were fully investigated. The polymerization effect is beneficial to lower the phase formation temperature and obtain smaller particle catalysts. Both methods can synthesize catalysts with excellent performance of visible-light degradation of methyl violet (MV). The Low-β BiNbO4 powder prepared by citrate method shows better degradation rate of about 1 h to decompose 80 % of MV and also displays good photocatalytic stability. The photodegradation of MV under the visible-light irradiation followed the pseudo-first-order kinetics according to the Langmuir-Hinshelwood model, and the obtained first-order rate constant and half-time are 2.85 × 10(-2) min(-1) and 24.3 min, respectively. The better photocatalytic performance of BiNbO4 powders prepared by citrate method can be attributed to its smaller band gap and better crystallinity.

No MeSH data available.


XRD patterns of BiNbO4 powders prepared by a citrate and b Pechini methods, respectively. The powders are thermally treated at different temperatures for 3 h
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Fig1: XRD patterns of BiNbO4 powders prepared by a citrate and b Pechini methods, respectively. The powders are thermally treated at different temperatures for 3 h

Mentions: Figure 1 gives the XRD patterns of BiNbO4 powders prepared by citrate and Pechini methods. In Fig. 1a, it can easily be seen that there is no apparent β-BiNbO4 peaks at 550 °C, only an intermediate phase of Bi5Nb3O15 is formed. With the temperature increase, Bi5Nb3O15 transformed to β-BiNbO4 gradually and pure Low-β BiNbO4 is obtained at 700 °C. Due to the polymerization effect between CA and EG in the Pechini process, the appearance of Low-β BiNbO4 seems much easier, as shown in Fig. 1b. Even at 500 °C, Low-β BiNbO4 has been formed and coexisted with the Bi5Nb3O15 phases. At 550 °C, quite different from that of the citrate method, Low-β BiNbO4 is the major phase and pure Low-β BiNbO4 is also obtained at 700 °C. Low-β BiNbO4 is thermodynamically unstable and transforms to α phase at 900 °C, the same as in other literatures [15]. The differences of the phase formation process can be attributed to the polymerization effect between CA and EG. In the citrate process, the solution consists of Nb-CA and Bi-citrate (Bi-CA) metal complexes and is weakly interconnected by van der Waals or hydrogen bonding; while for the Pechini process, Nb-CA and Bi-CA were coordinated by the polymerization effect between CA and EG to form a homogeneous multicomponent gel, which is crucial for complex oxide preparation [18].Fig. 1


The Polymerization Effect on Synthesis and Visible-Light Photocatalytic Properties of Low-Temperature β-BiNbO4 Using Nb-Citrate Precursor.

Zhai H, Kong J, Wang A, Li H, Zhang T, Li A, Wu D - Nanoscale Res Lett (2015)

XRD patterns of BiNbO4 powders prepared by a citrate and b Pechini methods, respectively. The powders are thermally treated at different temperatures for 3 h
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4666192&req=5

Fig1: XRD patterns of BiNbO4 powders prepared by a citrate and b Pechini methods, respectively. The powders are thermally treated at different temperatures for 3 h
Mentions: Figure 1 gives the XRD patterns of BiNbO4 powders prepared by citrate and Pechini methods. In Fig. 1a, it can easily be seen that there is no apparent β-BiNbO4 peaks at 550 °C, only an intermediate phase of Bi5Nb3O15 is formed. With the temperature increase, Bi5Nb3O15 transformed to β-BiNbO4 gradually and pure Low-β BiNbO4 is obtained at 700 °C. Due to the polymerization effect between CA and EG in the Pechini process, the appearance of Low-β BiNbO4 seems much easier, as shown in Fig. 1b. Even at 500 °C, Low-β BiNbO4 has been formed and coexisted with the Bi5Nb3O15 phases. At 550 °C, quite different from that of the citrate method, Low-β BiNbO4 is the major phase and pure Low-β BiNbO4 is also obtained at 700 °C. Low-β BiNbO4 is thermodynamically unstable and transforms to α phase at 900 °C, the same as in other literatures [15]. The differences of the phase formation process can be attributed to the polymerization effect between CA and EG. In the citrate process, the solution consists of Nb-CA and Bi-citrate (Bi-CA) metal complexes and is weakly interconnected by van der Waals or hydrogen bonding; while for the Pechini process, Nb-CA and Bi-CA were coordinated by the polymerization effect between CA and EG to form a homogeneous multicomponent gel, which is crucial for complex oxide preparation [18].Fig. 1

Bottom Line: The polymerization effect is beneficial to lower the phase formation temperature and obtain smaller particle catalysts.The Low-β BiNbO4 powder prepared by citrate method shows better degradation rate of about 1 h to decompose 80 % of MV and also displays good photocatalytic stability.The better photocatalytic performance of BiNbO4 powders prepared by citrate method can be attributed to its smaller band gap and better crystallinity.

View Article: PubMed Central - PubMed

Affiliation: Henan Key Laboratory of Photovoltaic Materials, College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, 453007, People's Republic of China. haifazhai@126.com.

ABSTRACT
Low-temperature β-BiNbO4 powders (denoted as Low-β) were prepared by citrate and Pechini methods using homemade water-soluble niobium precursors. The addition of ethylene glycol and the resultant polymerization effect on the synthesis and visible-light photocatalytic performance of β-BiNbO4 powders were fully investigated. The polymerization effect is beneficial to lower the phase formation temperature and obtain smaller particle catalysts. Both methods can synthesize catalysts with excellent performance of visible-light degradation of methyl violet (MV). The Low-β BiNbO4 powder prepared by citrate method shows better degradation rate of about 1 h to decompose 80 % of MV and also displays good photocatalytic stability. The photodegradation of MV under the visible-light irradiation followed the pseudo-first-order kinetics according to the Langmuir-Hinshelwood model, and the obtained first-order rate constant and half-time are 2.85 × 10(-2) min(-1) and 24.3 min, respectively. The better photocatalytic performance of BiNbO4 powders prepared by citrate method can be attributed to its smaller band gap and better crystallinity.

No MeSH data available.