Microwave-synthesized γ-WO3 nanorods exhibiting high current density and diffusion characteristics

IF 1.6 4区化学 Q3 CHEMISTRY, INORGANIC & NUCLEAR

Transition Metal Chemistry Pub Date : 2023-05-26 DOI:10.1007/s11243-023-00533-y

Shreya, Peeyush Phogat, Ranjana Jha, Sukhvir Singh

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引用次数: 2

Abstract

The synthesis of monoclinic (γ) tungsten oxide (WO₃) nanorods via facile Microwave-assisted hydrothermal route is reported in the present work. The structural characterization of the as-synthesized material by using X-ray diffraction and Fourier-transform infrared spectroscopy confirms the formation of crystalline WO₃ phase. The morphology and microstructural study along with elemental composition of the material as obtained by scanning electron microscopy and transmission electron microscopy, respectively, reveals the generation of one-dimensional WO₃ nanorods. The nanorods show substantial absorbance in the ultraviolet (UV) region with the bandgap and refractive index of 2.7 eV and 2.48, respectively. Here, the low value of bandgap without adding any catalyst or co-catalyst is attributed to the microwave treatment. The electrochemical properties of WO₃ are studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The nanorods show high current density at different potentials and diffusion-controlled behavior as exhibited by Warburg impedance. The anodic as well as cathodic peak current values are seen to be increased after the deposition of the thin film of FTO substrate indicating the better diffusion of ions in the electrolyte. The capacitive and diffusive contribution of the thin film is investigated at various scan rates using Dunn’s model which shows that the diffusive contribution of the thin film is 120 times more than the capacitive contribution confirming the diffusive behavior of the thin film. The exchange current density of the deposited film is calculated which is found to have higher value than that of bare FTO. I–V characteristics of WO₃ are compared with that of bare FTO which reveals the smaller resistance offered by WO₃ film. The equivalent circuit as obtained from Nyquist plot is used to estimate the resistance of electrolyte, film and charge transfer resistance along with the double-layer capacitance and Warburg impedance. Further, bode plot is analyzed to study the phase shift and thus the diffusive behavior of the material.

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微波合成的γ-WO3纳米棒具有高电流密度和扩散特性

本文报道了微波辅助水热法制备单斜(γ)氧化钨纳米棒。利用x射线衍射和傅里叶变换红外光谱对合成材料进行了结构表征，证实了WO3结晶相的形成。通过扫描电镜和透射电镜分别对材料的形貌和微观结构以及元素组成进行了研究，揭示了一维WO3纳米棒的生成。纳米棒的带隙和折射率分别为2.7 eV和2.48 eV，在紫外区具有良好的吸光度。在不添加任何催化剂或助催化剂的情况下，低带隙值归因于微波处理。采用循环伏安法(CV)和电化学阻抗谱法(EIS)研究了WO3的电化学性能。纳米棒在不同电势下具有较高的电流密度和Warburg阻抗的扩散控制特性。FTO衬底薄膜沉积后，阳极和阴极峰值电流值均增加，表明离子在电解质中的扩散更好。利用Dunn模型研究了不同扫描速率下薄膜的电容和扩散贡献，结果表明薄膜的扩散贡献是电容贡献的120倍，证实了薄膜的扩散行为。计算了沉积薄膜的交换电流密度，发现其值高于裸FTO。对比了WO3薄膜与裸FTO的I-V特性，发现WO3薄膜的电阻更小。利用Nyquist图得到的等效电路，估计了电解质电阻、薄膜电阻和电荷转移电阻以及双层电容和Warburg阻抗。此外，还分析了波德图来研究相移，从而研究材料的扩散行为。

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来源期刊

Transition Metal Chemistry 化学-无机化学与核化学

CiteScore

3.60

自引率

0.00%

发文量

审稿时长

1.3 months

期刊介绍： Transition Metal Chemistry is an international journal designed to deal with all aspects of the subject embodied in the title: the preparation of transition metal-based molecular compounds of all kinds (including complexes of the Group 12 elements), their structural, physical, kinetic, catalytic and biological properties, their use in chemical synthesis as well as their application in the widest context, their role in naturally occurring systems etc. Manuscripts submitted to the journal should be of broad appeal to the readership and for this reason, papers which are confined to more specialised studies such as the measurement of solution phase equilibria or thermal decomposition studies, or papers which include extensive material on f-block elements, or papers dealing with non-molecular materials, will not normally be considered for publication. Work describing new ligands or coordination geometries must provide sufficient evidence for the confident assignment of structural formulae; this will usually take the form of one or more X-ray crystal structures.