CO2 hydrogenation to C5+ isoalkanes on ZnZr/HZSM-5 composite catalyst

Data generation procedures, data processing methods and steps, equipment and tools used:The performance evaluation of CO2 hydrogenation was carried out in a fixed bed reactor. First, the 2.4g oxide or 3 g composite catalyst was loaded into the reactor, and the catalyst was reduced for 12 h at 340 °C by diluted hydrogen flow (10% H2+90%N2). After reduction, the reaction gas (H2/CO2/N2= 72/24/4) was passed into the reactor. The reaction pressure is 5MPa, the reaction temperature is 340 °C, and the space speed is 3000mL/g /min. The flow rate remains constant at 150 mL/min. The line from the end of the reactor to the gas chromatograph is heated to 140 °C through the heating belt to prevent condensation of high-carbon hydrocarbon products. All gas products were analyzed by two on-line gas chromatography and one off-line chromatography. The TCD detector and carbon molecular sieve column were used to analyze H2, CO, CH4 and CO2, and the FID detector and GDX-403 column were used to analyze low carbon hydrocarbons and oxygen-containing compounds (methanol and dimethyl ether). FID detector and GS-Alumina capillary column (0.53 mm×50 m) were used for the analysis of all hydrocarbons and aromatics. The conversion of CO2 was calculated with N2 as the internal standardThe molar ratio of ZnZr oxide was determined by Varian ICP-OES 720 inductively coupled Plasma Emission Spectrometer (ICP). The SiO2/Al2O3 ratio of the HZSM-5 zeolite was determined by Panaco Zetium X-ray fluorescence spectrometer (XRF).X-ray diffraction (XRD) patterns of all oxides and HZSM-5 zeolites were measured on the MiniFlex 600 diffractometer under the following conditions: Cu Kα ray source, voltage 40 kV, current 15 mA, scanning in the range of 2θ = 5−80°, step size 0.02°, scanning rate 4°/ min.Scanning electron microscopy (SEM) images and energy dispersive spectroscopy (EDS) analysis were obtained on the JSM-7900F to analyze the oxide morphology and surface composition of ZnZr. JEM-2100F high resolution transmission electron microscopy (HRTEM) was used to measure the fringe spacing of oxides to get a comprehensive understanding of the crystal structure.N2 physical adsorption was carried out on the BELSORP physical adsorption instrument. Before the adsorption experiment, the samples were first degayed under vacuum at 300 °C for 10 h to remove the adsorbed water and impurities on the surface. After the treatment, the sample tube was transferred to the test station, and the dewar bottle was filled with enough liquid nitrogen to keep the sample temperature at 77 K, and the test procedure was started. BET (Brunauer-Emmett-Teller) method was used to calculate the surface area of the sample, and t-plot method was used to calculate the micropore area and volume.The acidic and alkaline sites on the catalyst surface were obtained by automatic temperature-programmed chemisorption (BELCAT). The specific operation of NH3 temperature programmed desorption (NH3-TPD) is as follows: 50 mg ZnZr oxide is taken and pretreated at 400 °C for 2 h under He gas (50 mL/min) purging. After cooling to 100 °C, NH3 was injected until adsorption saturation, and He gas was purged for a certain time to remove the NH3 physically adsorbed on the sample surface. Then, the NH3-TPD curves were obtained at a rate of 10 °C/min in the temperature range of 100−600 °C. The test process of CO2 programmed temperature desorption (CO2-TPD) is as follows: Take 50 mg ZnZr oxide and reduce it at 340 °C under H2/N2 mixture (50 mL/min) for 1 h, then cool it to 50 °C, CO2 adsorption for 0.5 h, introduce He gas to purge the physical adsorption of CO2, The CO2-TPD curve was recorded from 50−700 °C at a heating rate of 10 °C/min.X-ray photoelectron spectroscopy (XPS) was tested using the US ESCALAB 250Xi photoelectron spectrometer, with the C-1s peak of 284.6eV as the reference. Electron paramagnetic resonance spectroscopy (EPR) was tested using the Brooke EMXplus instrument. Prior to XPS and EPR measurements, ZnZr was first pre-reduced in H2 at 340 °C for 2 h, and EPR measurements were performed at 100 K.in situ DRIFT spectroscopy was obtained on the Bruker Tensor 27 FT-IR spectrometer. Before the test, the samples were pretreated with Ar at 340 °C for 0.5 h, and then reduced with H2 for 1 h. The background was swept, and the reaction gas (H2/CO2/N2= 72:24:4) was introduced. The absorption spectra at different times were recorded.Description of data file:Figure 1(a-e)origin curve and original experimental data; Figure 2. (a, b)origin curve, (c-e)SEM and excel data list; Figure 3. (a)origin curve, (b-d)TEM; Figure 4. (a, b) excel data list of origin curve; Figure 5. (a, b) excel data list of origin curve; Figure 6. (a-c) excel data list of origin curve; Figure 7. (a, b) excel data list of origin curve; Figure 8. (a-d) excel data list of origin curve; Summary Figure: pptx