The present invention provides a process and catalyst system for the production of synthesis gas (a mixture of CO and H2) from greenhouse gases like methane and carbon di oxide. The process provide a single step selective reforming of methane with carbon dioxide to produce synthesis gas over Ce—Ni—MgAl2O4 catalyst prepared by using combination of two methods evaporation induced self-assembly and organic matrix combustion method. These suitably combined methods generate a unique catalyst system with very fine Ni nano clusters evenly dispersed in high surface area support. The process provides both Methane and carbon di oxide conversion more than 90% without any noticeable deactivation till 100 hours between temperature range of 500-800° C. at atmospheric pressure.