Fabrication and Characterization of Cobalt Nanostructure-Based Microelectrodes for Phosphate Detection

Abstract

This paper presents the fabrication procedure and characterization of cobalt nanostructure-based microelectrodes for phosphate detection. Cobalt thin films with different plane, nano-scale structures were obtained on gold microelectrodes by adjusting the parameters of electrodepositing method. The result of the fabrication was examined by XRD and SEM, showing the crystal direction and surface morphology of the electrodeposited cobalt layer. Electrochemical characterization of these microelectrodes was performed. The electrodes deposited under different parameters present a linear response in the range from 10-6mol/L to 10-2mol/L with a slope ranging from -19 to -17.6mV/decade. The potential response becomes stable in 200s after the electrode was put into the phosphate solution. It could be assumed that the difference in surface morphology of the electrode caused by changing depositing parameters may have little affection to the response to phosphate.

Assessment of a Solid-State Phosphate Selective Electrode Based on Tungsten

“…This cobalt-based phosphate electrode has been used throughout many studies. [8][9][10][11][12][13][14][15][16][17][18][19] This electrode requires the formation of cobalt oxide during pretreatment before each measurement, and the potential is influenced by dissolved oxygen concentration in the sample and stirring rate. 20 More recently, a phosphate sensor based on molybdenum has been reported.…”

“…Based on this phenomenon, it can be z E-mail: shangbinx@163.com expected that also other transition metals, with similar chemical properties, have a Nernst response to HPO 4 2− . While the reported performance of molybdenum-based sensors was often better than that of cobalt-based sensor, [8][9][10][11][12][13][14][15][16][17][18][19]21 it is potentially valuable to explore metals with similar chemical properties as molybdenum. Tungsten, which is in the same group as molybdenum, is more metallic and therefore is more likely to provide electrons in redox reactions.…”

Phosphate Sensor Using Molybdenum

“…z E-mail: 1284572097@qq.com After the surface-modified, a cobalt-based phosphate-sensitive electrode was introduced for phosphate measurement by Xiao et al 20 The cobalt is extensively used for detecting phosphate. [21][22][23][24][25][26][27][28][29] Before measurement, the electrode needs to be pretreated to form cobalt oxide, and the measurement accuracy is impacted by dissolved oxygen and stirring rate. 4 A monohydrogen phosphate ion-selective polymeric membrane electrode is proposed based on phenyl urea substituted calix [4]arene.…”

Review—Solid State Sensors for Phosphate Detection in Environmental and Medical Diagnostics

“…Another group published two studies on a 400 μm cobalt microelectrode fabricated using a standard microfabrication process. 40,41 Cobalt was electroplated on a metallized glass substrate similar to previous studies. After fabrication, the electrode was chemically pretreated in DI water for 2 min followed by an exposure to 10 −4 M H 2 PO 4 − solution for 400 s. The phosphate concentrations were measured in 25 mM potassium hydrogen phthalate buffer at pH 7.5.…”