In recent years, recycling of CO2 to methane by catalytic reduction (CO2 + 4 H2 → CH4 + 2 H2O), called CO2 methanation or Sabatier reaction, has gained wide popularity. For simulating a reactor, kinetic model is needed to describe the reaction as a source term in the transport equations. Catalytic reactions consist of processes that span a wide range of time and length scales, viz. adsorption, desorption and surface reactions occurring at the microscale and gradients of temperature, velocity, concentration etc. at the macroscale. The available kinetic models in literature for Sabatier reaction are empirical power law equations fitted to macroscale experimental data. Such models are inadequate when information at microscale, such as reaction pathways and intermediate surface species are needed. A microkinetic model comprising of the elementary steps occurring on the catalyst surface during Sabatier reaction has been developed using theoretical methods. Using such a model, reactor level simulations work with a bottom-up modelling strategy where overall conversion is predicted from microscale calculations. The microkinetic model that we developed is able to predict multiple experimental data in literature. Further analyses conducted on this model has revealed the possible pathway of reaction flux. Details of the model development and analysis will be discussed in the talk.