Global warming is the major environmental thread in the 20^th century. According to IPCC (Intergovernmental Panel on Climatic Change), in the mid-20^th century they observed increase in globally averaged temperature due to the increase in anthropogenic greenhouse gas concentrations that leads to the warming of the Earth surface. The greenhouse effect arises mainly due to carbon dioxide, methane and other atmospheric gases absorb outgoing infrared radiation resulting in the raising of temperature. In its turn, especially CO₂ is blamed to be the main reason for causing greenhouse effect. Carbon dioxide is not only anthropogenic; it is also the cause for climatic changes and various natural processes like ocean changes in CO₂ solubility.

Hence in this present investigation, we have decomposed the CO₂ by a novel green solid acid catalyst. It is synthesized by using a simple sol-gel method. AlPO₄ and ZnAlPO₄ are synthesized by using n-butyl amine as the template. These materials are characterized by FT-IR, SEM, BET and XRD analysis for confirming the tetrahedral framework, morphology, surface area and pore size and crystalline nature of the material, respectively. The catalytic performance of carbon dioxide decomposition is evaluated over AlPO₄ and ZnAlPO₄ by using a specially designed U-shaped catalytic reactor. The effect of temperature, flow rate, catalytic dosages and time on stream is optimized for maximum carbon dioxide decomposition (99%) and selectivity of oxygen (52%) and carbon monoxide (48%) over AlPO₄ and ZnAlPO₄.