Autochem 2 2920

Commercial reagents were purchased from Sigma-Aldrich (ACS grade) and used as received unless otherwise noted. Powder XRD patterns were recorded with a Bruker AXS D8 Advance diffractometer by using nickel-filtered Cu-Kα radiation (λ=1.5406 Å). Scanning electron microscope images were taken by a JEOL JSM-7600 field-emission scanning electron microscope with an accelerating voltage of 5 kV. TEM images were taken by a JEOL JEM 2100 TEM at an accelerating voltage of 200 kV. ICP spectroscopy was conducted on a Dual-view Optima 5300 DV ICP-OEM system. The pH value of the reaction system was monitored by Mettler Toledo FE-20. The numbers of active sites on the surface of Pt were determined from CO chemisorption using an automated catalyst characterization system (Autochem II 2920) from Micromeritics Instrument Corporation equipped with a thermal conductivity detector. The samples were treated at 423 K for 60 min and then cooled to room temperature in a He flow of 50 ml min⁻¹. The CO chemisorption was measured at 293 K by introducing pulses of 5% CO–He flow (50 ml min⁻¹) until adsorption saturation. Stoichiometric factor (Pt:CO molar ratio in the chemisorption) is taken as 1.

SEM images were recorded on JSM-6510 microscopy and JEOL FE-SEM 6700 F microscopy. TEM images were obtained on JEOL JEM-2100F. CAs were measured on the Data-Physics OCA20 machine at ambient temperature and each value was obtained by measuring five different positions. Nitrogen adsorption-desorption measurements were carried out at 77.35 K on ASAP2020 after the samples being degassed at 350 °C under vacuum for 10 h. Fourier transform infrared spectrum was recorded from 400 to 4000 cm^-1 on a Nicolet Impact 410 FTIR spectrometer. The TPD experiments were performed by using a Micromeritics AutoChem II 2920 automated chemisorption analysis unit with a thermal conductivity detector under helium flow. The separation efficiency was measured by OIL480 infrared spectrometer oil content analyzer. Optical microscopy images were taken on a CMM-55E (Leica, Germany). The mechanical properties of the membranes were measured using a testing device 410R250 (TestResources, Shakopee, MN) and five samples were tested for each stack.

The effect of each preparation step on the catalyst morphology was investigated by field emission scanning electron microscopy (Hitachi, Tokyo, Japan, SU8020) at an accelerating voltage of 15.0 kV. The surface properties were determined by measuring the water contact angle using the static sessile drop method with a Contact angle analyzer (Phoenix 300, SEO, Suwon, Korea). The contact angle of the prepared catalysts (thickness = about 0.2 cm) was measured within 10 s after dropping water
The crystallinity of and impurities in the catalysts were analyzed using X-ray diffraction (XRD, Rigaku, Tokyo, Japan, Ultima IV) with Cu Kα (λ = 0.15406 nm) radiation in the 2θ range of 10° to 80° at a scan rate of 1°/min. The Si and N elements in the catalysts were measured by X-ray photoelectron spectroscopy (XPS; Thermo VG Scientific, Waltham, MA, USA, K Alpha+) with Al Kα radiation; the binding energy of C1s was normalized to 284.8 eV. Fourier transform infrared spectroscopy (FT-IR, Varian Medical Systems, Palo Alto, CA, USA, 670 FTIR) was carried out over a wavelength range of 400–4000 cm⁻¹.
H₂-temperature-programmed reduction was carried out using an AutoChem II 2920 (Micromeritics Instrument Corp., Norcross, GA, USA). The samples were exposed to a current of 10% H₂/Ar and measured in the 200–900 °C temperature range.

CO₂ adsorption–desorption profiles were collected by a TGA-MS setup (Supplementary Fig. 5). Before the measurements, PEI/SiO₂ and nEB-PEI/SiO₂ were degassed at 100 °C for 1 h under N₂ flow (50 cm³ min⁻¹). CO₂ adsorption was carried out using a simulated wet flue gas containing 15% CO₂, 3% H₂O, 2% Ar (the internal standard for MS calibration) and N₂ balance at 40 °C. After 30 min adsorption, the gas was switched to 100% CO₂ flow (50 cm³ min⁻¹) and the temperature was increased to 120 °C (ramp: 20 °C min⁻¹). Then the temperature was maintained for 30 min for the desorption process. The adsorption–desorption cycle was repeated 50 times. The adsorbed amount of CO₂ was calculated by subtraction of the adsorbed H₂O amount (determined with MS) from the total mass increase determined from TGA. To confirm the reliability of the TGA-MS results, CO₂ uptake was also cross-checked with an automated chemisorption analyser (Micromeritics, Autochem II 2920) specially equipped with a cold trap for H₂O removal in front of a thermal conductivity detector (Supplementary Fig. 6). In all measurements, samples were diluted 10 times by using sand (quartz) as a diluent for avoiding heat-transfer limitation.