Alcohols electrooxidation coupled with H2 production at high current densities promoted by a cooperative catalyst

Electrochemical alcohols oxidation offers a promising approach to produce valuable chemicals and facilitate coupled H2 production. However, the corresponding current density is very low at moderate cell potential that substantially limits the overall productivity. Here we report the electrooxidation of benzyl alcohol coupled with H2 production at high current density (540 mA cm−2 at 1.5 V vs. RHE) over a cooperative catalyst of Au nanoparticles supported on cobalt oxyhydroxide nanosheets (Au/CoOOH). The absolute current can further reach 4.8 A at 2.0 V in a more realistic two-electrode membrane-free flow electrolyzer. Experimental combined with theoretical results indicate that the benzyl alcohol can be enriched at Au/CoOOH interface and oxidized by the electrophilic oxygen species (OH*) generated on CoOOH, leading to higher activity than pure Au. Based on the finding that the catalyst can be reversibly oxidized/reduced at anodic potential/open circuit, we design an intermittent potential (IP) strategy for long-term alcohol electrooxidation that achieves high current density (>250 mA cm−2) over 24 h with promoted productivity and decreased energy consumption.

Electroanalysis with a single microbead of phosphate binding resin (FerrIX™) mounted in epoxy film

Commercial resin microbeads are widely applied in ion exchange and extraction. Here, a single anion-selective and phosphate binding resin microbead (FerrIX™) is mounted into an epoxy membrane and investigated by 4-electrode membrane voltammetry and membrane impedance spectroscopy. Anion transport properties are observed to dominate associated with three distinct potential domains: (I) a low bias ohmic potential domain (dominant at high electrolyte concentration), (II) a concentration polarisation potential domain, and (III) an over-limiting potential domain. Voltammetric responses show transient diffusion-migration features at higher scan rates and quasi-steady state features at lower scan rates. Inherent microbead conductivity is shown to be linked to two resistive elements, electrolyte concentration dependent and independent, in series. The effects of phosphate binding are revealed as transient pattern in impedance spectroscopy data. Preliminary data suggest phosphate concentration-dependent peak features in the imaginary impedance versus frequency plot due to phosphate binding into the microbead. Graphical abstract

On the Effect of Anion Exchange Ionomer Binders in Bipolar Electrode Membrane Interface Water Electrolysis

Bipolar membrane|electrode interface water electrolyzers (BPEMWE) were found to outperform a proton exchange membrane (PEM) water electrolyzer reference in a similar membrane electrode assembly (MEA) design based on individual porous...

Development of Potentiometric Phenol Sensors by Nata de Coco Membrane on Screen-Printed Carbon Electrode

Nata de coco, a bacterial cellulose as a result of coconut water fermentation, is a conductive polymer with a electrical conductivity of 553 μS/cm and has high mechanical stability. In this study, nata de coco was used as a supporting membrane for the development of phenol sensors in potentiometry. Nata de coco membrane containing phenol is coated on the surface of the printed carbon electrode (screen-printed carbon electrode). The cross-sectional area of the carbon electrode coated with the membrane is 1.5 × 3 mm2, while the reference electrode is Ag/AgCl. The thickness of the electrode membrane affects the Nernstian factor. The optimum Nernstian factor is produced by 100 μm membrane thickness containing 117.5 μg of phenol. Measurement of phenol solution was carried out at pH 11, in the concentration range of 10−8 to 10−2 mol/L, resulting in a Nernstian factor of 41.8 ± 1.3 mV/decade. The Nernstian factor increased to 55.7 ± 0.4 mV/decade if the membrane of the electrode contained 0.1% Fe3O4 nanoparticles. This sensor has been applied in the real sample of river water, resulting in good accuracy and precision.

The Study of Cylindrical Polymer Fuel Cell's Performance and the Investigation of Gradual Geometry Changes' Effect on Its Performance

To achieve an optimal perception of cardinal processes and prior to prototype fabrication to fuel cell optimization, modeling is extensively used in industrial researches and applications to transfer mass and heat into small-sized channels. In the current study, Computational Fluid Dynamics is presented to cylindrical polymer fuel cell with circular and elliptical cross-section. Concurrently, the design of fractured electrode-membrane assembly is introduced. The simulations explicitly demonstrate comparing to Base case production, the fractured case of the Electrode Membrane Assembly produces more current. Likewise, a new design for cylindrical polymer fuel cell is illustrated. In the cylindrical design, both the effect of gradual geometric changes on the performance including radius changes and the transformation of cross-section from circle to ellipse has been investigated and compared to Base case. The obtained results displays the cylindrical fuel cell’s better performance compared to Base case. Accordingly, establishing wider passage, in same volume for reactive gases toward reaction areas, results in sharp increase in the performance. Finally, validating simulation with valid laboratory results, proper correspondence is achieved.