Cell designs for the electrochemical reduction of CO 2 from gas phase were developed and investigated, and the critical elements for an efficient process were identified. Various types of polymeric membrane were used to build membrane electrode assembly adapted for CO 2 reduction in gas phase: protonic and anion exchange membrane (AEM), bipolar membrane and a modified bipolar like membrane configuration. Configurations using anion exchange ionomer in the cathodic catalytic layer in contact with an AEM allow for a great enhancement of the cathode reaction selectivity toward CO. However, a severe problem was identified when co-electrolysis is performed using only an AEM: this type of membrane acts as a CO 2 "pump" meaning that for each molecule of CO 2 reduced at the cathode, one or two CO 2 molecules are produced at the anode by oxidation of the carbonate/bicarbonate anion transported in the membrane. A bipolar membrane system was shown to soften this problem, but only a newly developed cell design was able to fully prevent the parasitic CO 2 pumping. Using this new cell configuration, the faradaic efficiency of an alkaline environment is maintained, the parasitic CO 2 pumping to the anode side is completely suppressed, and the overall cell voltage efficiency is highly improved.

A multivariate calibration method for mass spectrometry is presented that enables a quantitative analysis of gas mixtures containing interfering gases that contribute to the same mass‐to‐charge ratios at nominal resolution. Multiple calibration gas mixtures with linearly independent compositions are used in order to obtain the calibration constants for the contribution of each gas to each of the mass‐to‐charge ratio peaks. The method was successfully applied to the quantitative detection of CO in a mixture with CO2 and N2, which represents a difficulty commonly encountered in heterogeneous catalysis and electrocatalysis research.

Fuel cell electric vehicles (FCEVs) are a possible sustainable and long-term solution to satisfy the demand for mobility. Cost targets are achieved by lowering platinum (Pt) loadings on the electrodes and using thinner membranes in the fuel cell system (FCS), maximizing the current density. Due to these measures, the FCS becomes more sensitive to contaminants, including those originating from crossover through the membrane. One of these contaminants -carbon dioxide (CO2) -causes effects that can be reversed, however, this process negatively influences the FCS lifetime. For this reason, operating conditions should be chosen so that minimal temporary losses are caused without causing further negative effects, such as degradation, in the FCS. This paper shows the effects of CO2 and O2 permeation occurring during operation of an FCS and proposes the possibility of mitigating the crossover via the right choice of membrane.

Anion exchange membranes (AEM) are well studied in the context of fuel cells and water electrolyzers, as they permit the use of non-noble catalysts. However, such alkaline systems have a notable drawback of carbonation when they are operated using atmospheric air, which is known to reduce the anion conductivity of the membrane. The (bi)-carbonate ions are removed from the membrane through the migration of hydroxide ions, also known as the self-purging mechanism. This carbonation effect of AEMs can be utilized to selectively remove CO2 from a dilute gas mixture (e.g., flue gas or air) and transport it across the membrane, as shown in Figure 1. Effective CO2 transport across the membrane can be enabled using hydrogen evolution and oxidation reactions in the presence of CO2 and alkaline media. This methodology differentiates itself from other membrane-based separation techniques, as it allows for low concentrations (<1%) of CO2 to be removed at a high fraction (>90%) from a gas stream. Significant developments are required to optimize such a system, reduce material costs and cell overpotentials, and allow for long-term operation. We performed preliminary experiments proving the concept of an electrochemical CO2 separation device utilising AEMs. Steady-state galvanostatic experiments with on-line non-dispersive infrared gas analysis have demonstrated the clear relationship between current density, cell potential, and CO2 pumped across the membrane for a wide range of inlet CO2 concentrations. Faradaic efficiencies for CO2 transport are strongly dependent on the inlet CO2 concentration and current density. Considerations for further development are discussed. Figure Caption: Schematic of AEM CO2 separator Figure 1