The importance of controlling extent of reaction has led to the strategy depicted in Figure ; application of external work to one or both of the two thermodynamic states perturbs the free energy landscape in favor of a new equilibrium extent of conversion. For example, work via compression of reactant gases in chemistries such as hydrogenation of hydrocarbons alter the free energy landscape in favor of saturated bonds, requiring high pressure hydrogen as a co-reactant. Dynamic oscillation of surface binding energies potentially permits work to be imparted directly to the surface reaction (Figure ). Since work is applied directly to the surface reaction, the free energy landscape between A and B is modified without changing the free energy of the gas phase species. A system of this type is depicted in Figure , with the minimum energy offset from equilibrium by ΔΔG. Thermodynamic work as a 'catalytic molecular pump' moving surface adsorbates from strong to weak binding could therefore permit reactor systems that achieve high catalytic conversion at thermodynamically unfavorable gas-phase conditions.