Sintesis dan pencirian teras-cangkerang berasaskan silika@MgO untuk penjerapan dan penukaran karbon dioksida kepada singas

Abstract

Carbon dioxide (CO2) is a greenhouse gas trapped in the terrestrial atmosphere. More CO2 is emitted by burning coal, petroleum, and other fossil fuels from factories. The released CO2 traps heat and causes global warming. Therefore, this study aimed to examine the effectiveness of silica@MgO core-shell adsorbents for CO2 adsorption and conversion to syngas via dry reforming of methane (DRM). SBA15@MgO and fibrous nanosilica@MgO (GNS@MgO) core-shells were synthesized using the hydrothermal method. The characterizations were carried out using X-ray diffraction (XRD), Fourier transform infrared spectroscopy–attenuated total reflectance (FTIR-ATR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), nitrogen physisorption, and temperature-programmed desorption of carbon dioxide (TPD-CO2). Then, CO2 physisorption was determined using Micromeritics ASAP 2020. For characterization of GNS@MgO dan SBA15@MgO, an XRD diffractogram showed the presence of an amorphous silica peak for GNS, a two-dimensional peak of hexagonal structure for SBA15, and a MgO peak index for both core-shells. ATR-FTIR analysis showed a shift of silica peaks due to the presence of MgO. TEM and FESEM analyses showed morphological changes on the surface for SBA15 and FS serving as cores. Besides, MgO was proven to have covered the silica core through FESEM-EDX mapping. The N2 isotherm adsorption analysis and BJH pore size distribution for both adsorbents showed type IV isotherms and H3 hysteresis curves assigned as mesoporous adsorbents and having plate-shaped particles. TPD-CO2 analysis showed different CO2 interactions and basic strength and contributed to the CO2 chemisorption. The physical adsorption of CO2 for SBA15@MgO (7.84 cm3/g) was higher than that of GNS@MgO (5.82 cm3/g). Meanwhile, the chemical adsorption of CO2 for GNS@MgO (2.15 mmol/g) was higher than that of SBA15@MgO (1.55 mmol/g). Next, XRD, ATR-FTIR, and N2 physisorption analyses and CO2 conversion to syngas through the DRM process was carried out on Ni and Co loaded on SBA15@MgO and GNS@MgO. For Ni and Co loaded on SBA-15@MgO and GNS@MgO, XRD analysis showed the presence of Ni and Co and changes in silica and MgO peaks. ATR-FTIR analysis showed no significant changes. All adsorbents still possessed an IV isotherm and an H3 hysteresis curve but a decrease in the adsorption quantity was observed. Ni/SBA15@MgO showed the best DRM performance of 95% CH4 conversion, 80% CO2 conversion, 40% H2 production, and H2/CO ratio = 0.86. Both SBA15@MgO and GNS@MgO were potential base materials in CO2 adsorption and DRM.