Exploiting the Balance Between Conductivity and Adsorption Capacity/Redox Electrocatalytic Ability In MIL-Based Porous Crystalline Materials for the Electrochemical Response

Abstract

MIL-53(Fe), MIL-101(Cr), and MIL-53(Al) were successfully prepared to modify an electrode surface. With the differences in porous textural parameters and metal nodes, the physical characteristics and electrochemical performance toward chloramphenicol (CAP) detection at each modified electrode were systematically evaluated via CV and DPV measurements. Both MIL-53(Fe)/SPE and MIL-101(Cr)/SPE exhibited excellent electrochemical performances by enhancement of the EASA value, electro-catalysis, adsorption capacity, diffusion, and interaction with the CAP molecules. MIL-101(Cr)/SPE with a huge BET, large pore volume, and good redox electro-catalysis of Cr3+ metal nodes significantly enhanced electrochemical response, despite it was still limited by poor adsorption capacity and diffusion due to the strong water- interaction of the Cr3+ centers and steric effect of the cramped microporous system. MIL-53(Fe) with a much smaller specific surface area and pore volume showed good electrocatalysis of Fe3+, along with high interact ability and large adsorption capacity with CAP through hydrogen bonding and weak interaction with water. In contrast, MIL-53(Al)/SPE possessed poor electrochemical performance due to weak electron conductivity and the lack of electrocatalytic sites. Therefore, a perfect balance in terms of the conductivity, adsorption capacity, and electro-catalysis in MIL materials still needs to be further preferred in electrochemical sensors.

A molybdenum disulfide/nickel ferrite-modified voltammetric sensing platform for ultra-sensitive determination of clenbuterol under the presence of an external magnetic field

“…From that, the electrochemical active surface area (EASA or A ) was calculated using the Randles–Sevcik equation (25 °C) as described by equation: 7,23,42,43 I p = (2.69 × 10 5 ) n 3/2 D 1/2 Aν 1/2 C where n stands for the number of the electron in a redox reaction, D represents the diffusion coefficient of 7.6 × 10 −6 cm 2 s −1 , A refers to the electrochemical active electrode surface area (cm 2 ), C indicates the bulk concentration of [Fe(CN) 6 ] 3−/4− . According to that, the value of EASA was calculated at about 0.153 cm 2 for bare SPE, 0.191 cm 2 for NFO/SPE, 0.229 cm 2 for MoS 2 /NFO, 0.202 cm 2 for MoS 2 –NFO (1 : 1)/SPE, and 0.209 cm 2 for MoS 2 –NFO (2 : 1)/SPE, respectively.…”

“…S2 †). In this case, the current response linearly increased in the increase of square root of the scan rate (n 1/2 ), corresponding to the regression equations: From that, the electrochemical active surface area (EASA or A) was calculated using the Randles-Sevcik equation (25 °C) as described by equation: 7,23,42,43…”

Enhanced sensing performance of carbaryl pesticide by employing a MnO2/GO/e-Ag-based nanoplatform: role of graphene oxide as an adsorbing agent in the SERS analytical performance

“…The EASA value was calculated based on the Randles–Sevick equation: 31–33 I p = 2.69 × 10 5 × n 3/2 D 1/2 ACv 1/2 where I p is the peak current intensity, n is the number of electrons transferred ( n = 1), D is the diffusion coefficient of [Fe(CN) 6 ] 3−/4− ( D = 6.5 × 10 −6 cm s −1 ), A is the EASA value, ν is the scan rate, and C refers to the bulk concentration of the redox probe. The value of EASA was estimated to be about 0.137 cm 2 for Ag/SPE, 0.212 cm 2 for MnO 2 /e-Ag_SPE, and 0.223 cm 2 for MnO 2 /GO/e-Ag_SPE.…”

An Optimized MnO2-Ag Nanocomposite-Based Sensing Platform for Determination of 4-nitrophenol in Tomato Samples: Influences of Morphological Aspect of MnO2 Nanostructures and Synergic Effect on Electrochemical Kinetic Parameters and Analytical Performance

“…This approach has not only been widely mentioned and attracted at bare screen-printed electrodes (SPEs) in particular and other commercial electrodes, in general. A series of materials have been investigated and evaluated such as metal/metal oxides (Au, 1 Ag, 2 ZnO, 3,4 Cu x O, 5 Fe x O y , 6 MoS 2 , 7 MnO 2 , [8] etc); carbonaceous materials (graphene, graphene oxides (GO), 9 carbon nanotubes, and carbon dots); conducting polymers; 10 ); metal-organic frameworks (MOFs); 13 even their composite structures (Au@Graphene, 14 MoS 2 @GO, 15,16 Ag-Fe 3 O 4 , 17 MnO 2 -graphene 18,19 ). Not an exception to that trend, both MnO 2 nanomaterials and Ag nanoparticles (AgNPs) have been used to modify electrode surfaces thanks to their unique features (low cost, high activity, nontoxicity, high electronic conductivity, biocompatibility, easy preparation, and tunable electrochemical redox chemistry).…”