Ni-Zn impregnated on hierarchical ZSM-5 from natural minerals as catalyst for carboxylation reaction of ethyne with CO₂

Carbon dioxide is one of the main gases that cause greenhouse gas emissions in the atmosphere. One way to reduce gas emissions is to convert CO₂ and produce high-value products. Because it is atmospherically inert, catalyst assists CO₂ to react with other compounds. In this research, hierarchical ZSM-5 was prepared from natural minerals as sources, which is Bayat zeolite and Bangka kaolin, then impregnated with bimetal Ni-Zn as a catalyst to convert CO₂ in the presence of ethyne to produce acrylic acid. Natural mineral-based hierarchical ZSM-5 was prepared using double template method, with TPAOH as a primary template that directed to MFI framework and PDDA-M as a secondary template that directed mesoporous structure. Impregnation of nickel (Ni) and zinc (Zn) bimetallic was conducted by co-impregnation method followed by reduction with H₂ gas flow. Material characterization such as FTIR, XRD, XRF, SAA, and SEM-EDX were conducted on the catalyst. FTIR analysis shows that there has been a complete decomposition of templates through calcination. XRD analysis shows the crystallinity of the hierarchical ZSM-5 natural which indicates the synthesis was successful. SEM analysis shows the morphology of the material with the coffin like-shaped which is characteristic of the ZSM-5. The EDS analysis shows percent loading of Ni and Zn in ZSM-5 respectively is 6.38 % and 3.23 %. The ethyne carboxylation reaction with CO₂ was carried out in a batch reactor with pressure variations of 1.5 bar, 2.5 bar, and 3.5 bar. The products formed were analyzed by HPLC.