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A flow cell based, bench-scale electrochemical system for generation of synthesis-gas (syn-gas) is reported. Sensitivity to operating conditions such as CO 2 flow, current density, and elevated temperature are described. By increasing the temperature of the cell the kinetic overpotential for the reduction of CO 2 was lowered with the cathode voltage at 70 mA cm -2 decreased by 0.32 V and the overall cell voltage dropping by 1.57 V. This equates to an 18% increase in cell efficiency. By closely monitoring the products it was found that at room temperature and 70°C the primary products are CO and H 2 . By controlling the current density and the flow of CO 2 it was possible to control the H 2 :CO product ratio between 1:4 and 9:1. The reproducibility of performing experiments at elevated temperature and the ability to generate syn-gas for extended periods of time is also discussed.

A pressurized electrochemical system equipped for continuous reduction of CO 2 is presented. At elevated pressures, using a Ag-based cathode, the quantity of CO which can be generated is 5 times that observed at ambient pressure with faradaic efficiencies as high as 92% observed at 350 mA cm −2 . For operation at 225 mA cm −2 and 60 • C the cell voltage at 18.5 atm was 0.4 V below that observed at ambient pressure. Increasing the temperature further to 90 • C led to a cell voltage below 3 V (18.5 atm and 90 • C), which equates to an electrical efficiency of 50%.

We demonstrate the presence of two types of commensurate, registered water monolayers with different densities at the RuO2(110)/bulk-water (0.1 M NaOH solution) interface with off-specular, oxygen crystal truncation rods. At anodic potentials (close to oxygen evolution), the extraneous water layer and the surface hydroxide layer form a bilayer with O-H-O bond distances similar to that of ice X. At cathodic potentials, the water molecules converted from the bridging OH molecules form a low-density water layer.

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