Controlling gas emissions: Versatile control of the selectivity of an oxide electrocatalyst in the oxygen‐ and chlorine‐evolution reactions was demonstrated by Zn substitution in RuO2 (see picture: O red, Cl green, Zn blue, Ru white). The incorporation of Zn into the rutile structure alters the cation sequence along the [001] direction and modifies the structure of the active sites for both gas‐evolution processes.

As a part of an ongoing investigation of the use of isoelectric focusing (IEF) in microfluidic devices, pH gradients were electrochemically formed and optically quantified in microfluidic channels using acid-base indicators. The microchannels consisted of two parallel 40-mm-long electrodes with an interelectrode gap of 2.54 mm; top and bottom transparent windows were separated by 0.2 mm. Gradients in pH were formed as a result of the electrochemical decomposition of water at an applied potential not higher than 2.5 V to avoid generation of gas bubbles. Solutions contained low concentrations of a single buffer. The stability of the pH gradients and their sensitivity to changes in initial conditions were investigated under static (nonflow) conditions. Isoelectric focusing of sample biological analytes, bovine hemoglobin and bovine serum albumin, was performed to illustrate the potential of "microfluidic transverse IEF" for use in continuous concentration and separation systems.

No abstract

Density Functional Theory (DFT) has proven to be an invaluable and effective tool for identifying highly active electrocatalysts for the oxygen evolution reaction (OER). Herein we take a computational approach in order to first identify a series of rare-earth pyrochlore oxides based on Ir and Ru as potential OER catalysts. The DFT-based phase diagrams, Pourbaix diagrams (E vs. pH), projected density of states (PDOS), and band energy diagrams were used to identify prospective OER catalysts based on rare earth Ir and Ru pyrochlores. The predicted materials were synthesized using the sprayfreeze freeze-drying approach to afford nanoparticulate oxides conforming to the pyrochlore structural type A 2 B 2 O 7 where A = Nd, Gd, or Yb and B = Ir or Ru. In agreement with the computed Pourbaix diagrams, the materials were found to be moderately stable under OER conditions. All prepared materials show higher stability as compared to the benchmark IrO 2 catalyst and the OER mass activity of Yb 2 Ir 2 O 7 and the ruthenate pyrochlores (Nd 2 Ru 2 O 7 , Gd 2 Ru 2 O 7 , and Yb 2 Ru 2 O 7) were also found to exceed that of the benchmark IrO 2 catalyst. We find that the OER activity of each pyrochlore series Page 1 of 40 ACS Paragon Plus Environment ACS Applied Materials & Interfaces 2 (i.e. iridate or ruthenate) generally improves as the size of the A-site cation decreases, indicating that maintaining control over the local structure can be used to influence the electrocatalytic properties.

The use of microfluidic channels formed by two electrodes made of gold or palladium to perform transverse isoelectric focusing (IEF) is presented as a means for continuous concentration and fractionation of proteins. The microchannels were 40 mm long with an electrode gap of 1.27 mm and a depth of 0.354 mm. The properties of pH gradients formed as a result of the electrolysis of water were influenced by variation of parameters such as the initial pH, ionic strength, and flow rate. Transverse IEF in pressure-driven flow is demonstrated using bovine serum albumin in a single ampholyte buffer as well as in multiple-component buffers. Experimental results of protein focusing compare well to predictions of a mathematical model. Optimal conditions for efficient continuous fractionation of a protein mixture are summarized and discussed.