Effect of residual ions of hydrothermal precursors on the thickness and capacitive properties of WO3 nanoplates

Publication date: 15 May 2020Source: Journal of Alloys and Compounds, Volume 823Author(s): Jinzhi Jia, Xu Dong Liu, Xiaojia Li, Linhong Cao, Meng Zhang, Botao Wu, Xiuwen ZhouAbstractThe morphology and size of nanostructures have been considered to be directly related to capacitive performance. Additionally, hydrothermal synthesis is a common method to control nanostructures. In practice, researchers paid more attention to the direct effect of “useful ions” on morphology or size of nanostructures, e.g. the combination and decomposition processes of H+ and WO42− to form WO3. Unfortunately, the effects of other incidental residual ions on the nanostructures have been often neglected. Herein, we add an extra procedure (cleaning the precursor) in the as-optimized hydrothermal synthesis routine to remove residual ions in the solution around tungstic acid colloids. A comparative study shows such an extra procedure would result in a further considerable reduction of WO3 nanoplates in the thickness by 50% and in a prominent enhancement of the specific capacitance from 203.5 F g−1 to 334.0 F g−1 at a scan rate of 2 mV s−1. The thin WO3 nanoplates also show outstanding cycle stability for 5000 cycles. Interestingly, when we refilled the precursors solution with the Na+ and Cl− ions again, the thickness of WO3 nanoplates gradually thickens as the increase of NaCl content. In this way, the effect of residual ions on the thickness of nanoplates has been experimentally ...
Source: Journal of Alloys and Compounds - Category: Chemistry Source Type: research