Facile Pretreatment of Three-Dimensional Graphene through Electrochemical Polarization for Improved Electrocatalytic Performance and Simultaneous Electrochemical Detection of Catechol and Hydroquinone

Abstract

Three-dimensional graphene (3DG) with macroporous structure has great potential in the field of electroanalysis owing to a large active area, excellent electron mobility and good mass transfer. However, simple and low-cost preparation of 3DG electrodes with high electrocatalytic ability is still a challenge. Here, a fast and convenient electrochemical polarization method is established to pretreat free-standing 3DG (p-3DG) to offer high electrocatalytic ability. 3DG with monolithic and macroporous structure prepared by chemical vapor deposition (CVD) is applied as the starting electrode. Electrochemical polarization is performed using electrochemical oxidation (anodization) at high potential (+6 V) followed with electrochemical reduction (cathodization) at low potential (−1 V), leading to exposure of edge of graphene and introduction of oxygen-containing groups. The as-prepared p-3DG displays increased hydrophilicity and improved electrocatalytic ability. As a proof of concept, p-3DG was used to selective electrochemical detection of two isomers of benzenediol, hydroquinone (p-BD) and catechol (o-BD). In comparison with initial 3DG, p-3DG exhibits increased reversibility of redox reaction, improved peak current and good potential resolution with high potential separation between p-BD and o-BD. Individual or selective determination of p-BD or o-BD in single substance solution or binary mixed solution is realized. Real analysis of pond water is also achieved.

Nanochannel array modified three-dimensional graphene electrode for sensitive electrochemical detection of 2,4,6-trichlorophenol and prochloraz

“…On the other hand, the cathodic reduction is then carried out in an aqueous phase. This electrochemical pre-activation can introduce ionic liquid and oxygen-containing groups on p-3DG, thereby improving its hydrophilicity and electrocatalytic performance ( Zhou et al, 2022b ). In addition, stable binding of VMSF on the surface of p-3DG is expected through the reaction between oxygen-containing groups (e.g., -OH group) and silanol groups.…”

“…Electrochemical polarization of 3DG electrodes was performed using an anodic oxidation in an organic phase followed by a cathodic reduction in an aqueous phase ( Zhou et al, 2022c ). The electrolyte for anodization was an acetonitrile solution containing the ionic liquid BMIMPF 6 (10%, V/V).…”

Highly Sensitive Electrochemical Detection of Paraquat in Environmental Water Samples Using a Vertically Ordered Mesoporous Silica Film and a Nanocarbon Composite

“…Porous materials have been used as important functional building blocks for the development of various high-performance sensors and nanofluidic osmotic power generators [ 14 , 15 , 16 ], taking advantage of the high porosity and surface area [ 17 , 18 ], efficient enrichment ability [ 19 , 20 ] and rapid mass transfer [ 21 ], as well as their ease of hybridization [ 22 , 23 , 24 ]. In particular, vertically ordered mesoporous silica films (VMSF) consisting of ultrasmall and uniform pores (2~3 nm), perpendicular silica nanochannels and high porosity exhibit unique characteristics in terms of their good molecular accessibility, high permselectivity (e.g., size [ 25 ], charge [ 26 ] and lipophilicity [ 27 ]) and excellent anti-fouling capacity [ 28 ].…”

Vertically-Ordered Mesoporous Silica Films for Electrochemical Detection of Hg(II) Ion in Pharmaceuticals and Soil Samples

“…Recently, porous materials as functional building blocks have been widely used for the construction of high-performance sensors, taking advantage of their ease of hybridization ( Cui et al, 2020 ; Cui et al, 2021 ; Duan et al, 2021 ; Liu et al, 2022 ), efficient enrichment ( Liang et al, 2021 ; Yan et al, 2021 ), and rapid mass transfer ( Zhou et al, 2022a ; Gong et al, 2022 ). Especially, vertically-ordered mesoporous silica films (VMSF) have been proven to be powerful preconcentration materials for electrochemical detection of metal ions, such as Cu 2+ ( Cheng et al, 2018 ; Lu et al, 2018 ), Hg 2+ ( Lu et al, 2018 ), Ag + ( Herzog et al, 2013 ), Pb 2+ ( Fernández et al, 2014 ; Cheng et al, 2018 ; Li et al, 2021 ), and Cd 2+ ( Cheng et al, 2018 ; Lu et al, 2018 ; Li et al, 2021 ).…”