The following content, obtained from https://doi.org/10.1016/j.jcou.2016.04.003, shows the procedure of ICCU-RWGS. The gas analysis was carried out using IR spectrometer.
“The experimental system mainly consists of four sections; (i) gas feed system, (ii) switching valve, (iii) reactor, (iv) gas detection system (IR/MS). In (i) there are two gas lines which allows preparing a gas mixture, one containing CO2, synthetic air, and nitrogen (capture phase gas), and another one containing H2 (reduction phase gas) at desired concentrations and flow rates. In order to investigate the effect of water, the nitrogen flow can be passed through the water saturator maintained at 30 °C. These two lines are connected to the (ii) switching valve and only one of the two gas mixtures enters the (iii) catalytic reactor and the other gas mixture goes to exhaust. There is a by-pass line at the reactor to measure ‘blank’ response of the gas flow under the same conditions for the flow controllers and detectors so that the results can be precisely calibrated and quantified. The effluent gas stream was passed into the transmission gas cell of an IR spectrometer (Bruker ALPHA) for quantitative product analysis. All valve switching and spectrum acquisition were synchronized by means of dedicated LabVIEW program in order to facilitate the data analysis and also precisely average over a number of CCR cycles to increase the S/N of the data.
In each run 1 g of the catalyst was used. Prior to the testing it was pressed, crushed, and sieved to the range of 200–300 μm. The catalyst was heated up to 450 °C under 45 mL min−1 N2 flow and then activated at the temperature under unsteady-state conditions (30 cycles) with alternating flows of 45 mL min−1 of N2 saturated with water and pure H2 for 90 s for each phase. This activation procedure was chosen to aim at avoiding over-reduction of the catalyst and partially reducing the hematite (Fe2O3) to magnetite (Fe3O4) as well as any CrO3 present in the catalyst to Cr2O3 [13]. Moreover, we performed a blank test in each experiment using a fixed bed of an inert material (SiC) with the same particle size (200–300 μm) and passing the same feed gas compositions used in the catalytic tests.”