Metal ion effect on pore size reduction in Mesoporous Aluminosilicate in the presence of TETA as a template and its catalytic performance of CO₂ decomposition at lower temperature

Mesoporous AlSiO4-33 and Co2+ incorporated Co-AlSiO4-15 catalysts are synthesized at room temperature using Triethylenetetramine (TETA) as a template for the purpose of CO2 decomposition. The prepared materials are characterized by FT-IR, XRD, UV-DRS, BET, TGA, Al-27 NMR and TEM. Based on XRD data, the materials are crystalline in nature. The mesoporosity of the materials with pore sizes of 33 nm (AlSiO4) and 15 nm (Co-AlSiO4) are confirmed by BET analysis. Consequently, we designated AlSiO4 and Co-AlSiO4 as AlSiO4-33 and Co-AlSiO4-15. This lowered diameter value for Co-AlSiO4-15 may be due to the octahedral coordination of Co2+ ion. In the tetrahedral aluminosilicate framework, the template directs the Co2+ towards octahedral coordination. Due to the octahedral coordination, the bond angle between Si-O-Co is reduced. Due to this reduction, the pore size reduced from 33 nm (AlSiO4-33) to 15 nm (Co-AlSiO4-15). These two catalysts are applied for CO2 decomposition. AlSiO4-33 is active at 100 degrees C while Co-AlSiO4-6 is active at 150 degrees C. Co-AlSiO4-15 has produced more oxygen than AlSiO4-33. It may be due to the Co-AlSiO4-15 has more bronsted acidic sites than the AlSiO4-33. Co-AlSiO4-15 is reduced the activation energy 67 % while AlSiO4-33 is reduced 78 % for CO2 decomposition at lower temperatures compare to conventional methods.