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

Abstract

AbstractMesoporous 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, 27Al 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 °C while Co‐AlSiO4‐6 is active at 150 °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.