ABSTRACT
Electroactive bacteria, including electrigenic bacteria (exoelectrogens) and electroautotrophic bacteria, implement microbial bioelectrocatalysis processes via bi-directional exchange of electrons and energy with environments, enabling a wide array of applications in environmental and energy fields, including microbial fuel cells (MFC), microbial electrolysis cells (MEC), microbial electrosynthesis (MES) to produce electricity and bulk fine chemicals. However, the low efficiency in the extracellular electron transfer (EET) of exoelectrogens and electrotrophic microbes limited their industrial applications. Here, we reviewed synthetic biology approaches to engineer electroactive microorganisms to break the bottleneck of their EET pathways, to achieve higher efficiency of EET of a number of electroactive microorganisms. Such efforts will lead to a breakthrough in the applications of these electroactive microorganisms and microbial electrocatalysis systems.
ABSTRACT
A highly stable multilayer film modified glassy carbon electrode (GCE) containing polydopamine (PDA) and Cu microparticles was fabricated by layer-by-layer self-assembly technique. The fabrication process was based on the self-polymerization of dopamine and electroless deposition of Cu microparticles on PDA coating. The fabrication process of multilayer films was characterized by UV-Vis spectra. The electrochemical performance of GCE / (PDA/ Cu) n modified electrode for glucose detection was investigated by cyclic voltammetry and amperometric current-time curve under alkaline conditions. At detection potential of 0. 35 V, the GCE / ( PDA/ Cu) 4 modified electrode presented a linear range of 0. 5 - 9. 0 mmol/ L with a detection limit of 5. 8 μmol/ L (S / N=3). Moreover, the sensitivity of the modified electrode was tunable by controlling the number of bilayers of the multilayer films. The modified electrode showed highly selective, stable and fast amperometric sensing of glucose. It was applied to determine glucose in human blood serum with satisfactory results.
ABSTRACT
The electro oxidation of methanol has been studied in alkaline medium NaOH 0.1 M and acid medium H2SO4 0.5 M on a platinum electrode and a platinum modified by adatom adsorption (Ni, Cu, Pb, and Cd). The influence of different experimental variables (methanol concentration, and temperature) is reported. Preliminary investigations by cyclic voltammetry showed that the catalytic activity of platinum is still too low to be considered as a practical catalyst. Underpotential deposition of lead, nickel, cadmium, or copper adatoms at platinum allowed increasing significantly the current densities.
ABSTRACT
Highly conjugated linear molecular wires are one of the basic elements for constructing molecular electronic devices. Among these conjugated compounds, ferrocene-terminated compounds as well as their derivatives have been widely studied because of their ideal electrochemical activity. Based on these, a new ferrocene-terminated phenylethynyaniline ( Fc-NH2 ) was synthesized by Sonogashira cross coupling reaction. The structure of the target compound was identified by infrared ( IR) , nuclear magnetic resonance ( NMR) , mass spectra ( MS) and cyclic voltammetry ( CV) . Combined the graphene-chitosan ( GH-CS) and Fc-NH2 , a new composite of GH-CS/Fc-NH2 was prepared and then used for immobilization of Cytc to prepare the GH-CS/Fc-NH2/Cytc/GCE. It was found from the CV result that a pair of peaks near-0. 2 V appeared which can be attributed to Cytc. The GH-CS/Fc-NH2/Cytc modified GCE showed good catalysis towards NaNO2 , and good linear relationship was found in the range of 1 ×10-7-1. 5 ×10-4 mol/L,and the determination limit was bellow 4×10-8 mol/L. Therefore, cytochrome c (Cytc) can be immobilized on the GH-CS/Fc-NH2 and the direct electron transfer can be realized between the electrode and solution and shows good prospect for detection of NaNO2 .
ABSTRACT
Praseodymium hexacyanoferrate film was modified on the graphite electrode by cyclic voltammetry in the solution of PrCl_3 and K_3Fe(CN)_6. Its electrochemical properties, including the influence of different scan rates, ions, and K~+ concentrations on the film, were studied. The membrane was characterized by IR and XPS. In IR spectrum, the vibration of cyano group verified from the formation of the film on the electrode. In XPS spectrum, the splitting of Fe2p_(1/2) )and Fe2p_(3/2)) showed that the valence of iron has been changed in the film formation, and a proper electropolymerization mechanism was put forward. The results showed the PrHCF film have some electrocatalytic activity to the oxidation of cysteine. The detection conditions for cysteine such as the potential and pH were also discussed.
ABSTRACT
Vitamin B1 self-assembled monolayer modified electrode (VB1-Au/SAMs/CME) was prepared and its electrochemical behavior was studied by cyclic voltammetry. The results showed that a self-assembled monolayer (SAM) was formed on the surface of gold electrode. \3-/4-redox couple was used as the electrochemical probe to study the electrochemical characteristics of SAM modified gold electrode and the results indicated that the existence of Vitamin B1 membrane on gold surface hindered the electron transfer. The electrochemical behaviors of dopamine(DA) and uric acid (UA) were investigated at VB1-Au/SAMs/CME. The results showed that the electrochemical oxidation of DA and UA could be electrocatalyzed. There were linear relationships between the anodic peak current and the concentration of DA(8.0×10-6-4.0×10-4 mol/L) and UA (6.0×10-5-2.2×10-4mol/L) respectively in differential pulse voltammograms. This modified electrode was effective to detect DA and UA in simultaneous determination of these species in a mixture.
ABSTRACT
A poly(amino black 10B)/Nafion modified glassy carbon(GC) electrode for the detection of dopamine(DA) has been developed. The modified electrode showed an excellent electrocatalytic effect on the oxidation of DA. In cyclic votammetric measurements, the redox peak current increased linearly with the concentration of DA in the range of 2.0×10~(-7) 3.0×10~(-5) mol/L in PBS of pH 6.0, with a correlation coefficient of 0.9993 and 0.9991, respectively. The detection limit(S/N=3) was 1.0×10~(-7) mol/L. Moreover, the modified electrode exhibited good repeatability and long-time stability, and avoided the interference of ascorbic acid. The modified electrode has been used for the determination of DA in the injections and calf serum with good recovery and reproducibility.