A reactor comprising at least one contact surface made from, coated with, or impregnated by a catalyst, wherein the contact surface comprises a sintered metal or a ceramic, and wherein the reactor is configured to subject a reactant stream to shear. A system for carrying out a heterogeneously catalyzed reaction, the system comprising a reactor as described above and a pump configured for delivering reactants to the at least one reactor. A method for carrying out a heterogeneously-catalyzed reaction by introducing reactants into a reactor comprising at least one contact surface made from, coated with, or impregnated by a catalyst under conditions which promote production of a desired product, wherein the contact surface comprises a sintered metal or a ceramic, and forming a dispersion of reactants within the reactor, wherein the dispersion comprises droplets or gas bubbles of reactant with an average diameter of less than about 5 μm.