Mediation of oxidation reactions at noble metal anodes by low levels of in situ generated hydroxy species

Electrochemical flow systems enable renewable energy industrial chain of CO2 reduction

The development of a comprehensive renewable energy industrial chain becomes urgent since renewable energy will soon dominate the power generation. Among the industries, carbon dioxide reduction reaction (CO2RR), which uses energy to convert carbon dioxide into high-value products and reduce CO2 in the atmosphere, is regarded as a promising and potential industrial application. The conventional H-type reactor shows limited catalytic activity toward CO2RR, leading to the incompatible combination with the massive renewable energy. The flow systems – flow-cell reactor and the membrane electrode assemblies – show the promising selectivity and activities of CO2RR products, meeting the criteria for industrial mass production. In this Perspective, I start by comparing the market price and annual global production of major CO2RR products with the necessary costs using technoeconomic analysis for industrial utilization. Subsequently, I systematically summarize the catalytic performances of the same copper catalyst in these reactors for CO2RR and discuss the possibility of industrialization. Owing to the distinctive catalytic behaviors in flow systems, I finally present prospects to investigate the catalytic mechanisms by developing various in-situ techniques in these flow systems to speed up the renewable energy industry.

Hydrazine as a hydrogen carrier in the photocatalytic generation of H2 using CdS quantum dots

The compelling need for safe storage and transportation of H₂ has made liquid-phase materials safer H₂-carriers with a high gravimetric and volumetric hydrogen density.

Physical vapor deposited highly oriented V2O5 thin films for electrocatalytic oxidation of hydrazine

The proposed work is focused on the effect of substrates on the electrocatalytic performance of physical vapor deposited vanadium pentoxide (V₂O₅) films.

Shape-selective synthesis of NiO nanostructures for hydrazine oxidation as a nonenzymatic amperometric sensor

In this work, we demonstrate the shape-dependent electrocatalytic activity of NiO NPs towards hydrazine oxidation.

Superaerophobic electrodes for direct hydrazine fuel cells

Direct liquid-feed fuel cells possess high energy and power densities, but suffer from severe adhesion of gas products. Here, a "superaerophobic" surface that enables a small release size and fast evolution behavior of the gas product is introduced, thereby, maximizing and stabilizing the working area. Consequently, the "superaerophobic" nanostructured Cu electrodes exhibit excellent performance as anodes in a direct hydrazine fuel cell.

Photoelectrochemical generation of hydrogen and electricity from hydrazine hydrate using BiVO4 electrodes

Photoelectrochemical production of energy from hydrazine hydrate containing aqueous solutions using a BiMo_0.02V_0.98O₄ photoanode under neutral pH conditions.

The mechanism of hydrazine electro-oxidation revealed by platinum microelectrodes: role of residual oxides

The electrochemistry of hydrazine at platinum has been re-evaluated by an investigation using microelectrodes. Platinum oxides remaining from preceding oxidative scans results in hydrazine oxidation occurring up to ca. 400 mV more cathodic than at an oxide-free Pt electrode. The observed voltammetry at oxidised or 'activated' platinum electrodes was found to be a function of the immersion time (time since 'activation') and pH. Differences between phosphate, sulphate and acetate-based electrolytes are noted. The anodic hydrazine oxidation features at 'activated' electrodes occurred as a prewave or a prepeak, depending upon the electrolyte and scan rate employed. Although hydrazine is known to react with bulk Pt oxide, the loss of activation with time was found to be independent of hydrazine concentration and was instead a function of pH and supporting electrolyte, therefore the 'activation' corresponds to residual rather than bulk platinum oxide. The condition of platinum was examined by X-ray photoelectron spectroscopy (XPS), which demonstrated an increase in oxygen coverage with cycling and the absence of any strongly adsorbed or poisoning species. The facile oxidation of hydrazine has implications with regards to hydrogen storage, generation and fuel cells. The different effects corresponding to insufficient buffering, which has relevance to the electroanalytical detection of hydrazine, was also investigated.

Novel Method for the Fast Determination of Ultra Trace Amount of Nortriptyline in its Pharmaceutical Formulations by Fast Fourier Transform Continuous Cyclic Voltammetric Technique at Au Microelectrode in Flowing Solutions

In this work a novel method for the determination of nortriptyline in flow-injection systems has been developed. The proposed method was used for the fast determination of nortriptyline in its pharmaceutical formulations. The developed technique is very simple, precise, accurate, time saving, and economical, compared to all of the previously reported methods. The effects of various parameters on the sensitivity of the method were investigated. The best performance obtained at pH value of 2, scan rate value of 30 V/s, accumulation potential of 400 mV, and accumulation time of 0.5 s. The proposed method has some advantages over other reported methods such as, no need for the removal of oxygen from the test solution, a subnanomolar detection limit, and finally the method is sufficiently fast for the determination of any such compound, in a wide variety of chromatographic methods. The potential waveform, consisting of the potential steps for cleaning, accumulation and potential ramp of analyte, was continuously applied on an Au disk microelectrode (12.5 microm in radius). The detection limit of the method was 2.0 x 10(-11) M. The relative standard deviation of the method at 1.2 x 10(-8) M was 2.1% for eight runs.

Development of fast Fourier transformation continuous cyclic voltammetry as a highly sensitive detection system for ultra trace monitoring of penicillin V

Fast continuous cyclic voltammetry was used as a detection method for penicillin V in a flow injection system. Additionally, a special computer-based numerical calculation method (using fast Fourier transformation) providing enhancement of the analyte signal and noise reduction is introduced here. During the measurements, the potential waveform (consisting of the potential steps of cleaning, stripping, and the potential ramp) was continuously applied to an Au disk microelectrode (12.5 microm in radius). In particular, the effects of accumulation potential, sweep rate, and delay time on the sensitivity and selectivity of the method were investigated. Eventually, the stripping time was found to be less than 300 ms, the detection limit of the method was 7.0x10(-12) M, and the associated relative standard deviation at 5.0x10(-6) M penicillin V was 2.3 for eight runs.

Selective and Non-Selective Determination of Heavy Metal Ions in Flowing Solutions by Fast Stripping Cyclic Voltammetry

A simple and fast stripping voltammetric detection method has been designed for selective and non-selective measurements of heavy metal ions in a flow-injection system. A special computer numerical method is introduced for calculating the analyte signal and noise reduction, where the signal is calculated based on the partial and total charge exchange at electrode surface. For a selective determination, the currents are integrated in the range of the oxidation and reduction of the analyte. For non-selective measurements, the integration range is set for the whole potential scan range (including oxidation and reduction of the Au surface). The time for stripping has been shown to be less than 300 ms. The main advantages of the detection method are as follows: first, removal of oxygen from the measured solution is not required; second, it is sufficiently fast for the determination of heavy metal ions in various chromatographic analysis methods. The limit of detection for tested ions was between 3 x 10(-9) and 6 x 10(-10) M, and the relative standard deviation at 50 ppb Pb2+ was 4.7% for 10 runs.