A Temporal Analysis of Products (TAP) reactor was used to study the mechanism of two green catalytic reactions, namely low-temperature CO oxidation on supported gold catalysts and volatile organic compounds (VOCs) elimination, with propane as model molecule, on vanadia-based catalysts. Single-pulse TAP experiments evidenced a weak and reversible adsorption of CO on Au/Ti(OH)4 catalyst and of propane on vanadia- based catalytic materials obtained by DC magnetron sputter deposition, while O2 adsorption was irreversible on both catalysts. Alternating TAP pulse experiments provided evidence for the nature of oxygen species involved in the oxidation reactions. If the adsorbed oxygen was involved in the CO oxidation, the lattice oxygen was responsible for the propane oxidation. Multi-pulse TAP experiments assessed the degree of reduction of the catalyst while its influence upon the mechanism is determined by single-pulse experiments. The obtained results will allow the optimal formulation of industrial scale catalysts with applicability to a wide range of industrial processes.