Catalysis accelerates a chemical reaction by providing an alternative pathway with reduced activation energy. This occurs by stabilizing transition states and modulating reaction kinetics.

A catalyst is a molecular or solid-phase entity that facilitates a chemical transformation by transiently interacting with reactants, altering their electronic or structural properties to enhance reaction rates. Catalysts function by stabilizing intermediate states and lowering the free energy barrier associated with the rate-determining step, thereby increasing the reaction efficiency.

Heterogeneous catalysis is a catalytic process, typically, in which a solid catalyst interacts with gaseous or liquid-phase reactants. This involves molecular adsorption onto active surface sites, bond activation through electronic perturbations, intermediate formation, and subsequent product desorption.

Reaction engineering is a branch of chemical engineering that focuses on the design, optimization, and scaling of chemical reactions to achieve desired reaction rates, selectivities, and efficiencies. It integrates the principles of thermodynamics, kinetics, transport phenomena, and catalysis to develop mathematical models to predict reactor performance under a variety of operating conditions.

Key variables in reaction engineering include temperatures, pressures, residence times, etc. Modulation of these variables can increase conversions, selectivities, and process efficiency.  

A systematic development of chemical reactors achieves desired reaction performance while optimizing conversion, selectivity, yield, and efficiency. This requires an understanding of the reaction kinetics, thermodynamics, transport phenomena, and process constraints for a given chemical transformation.