NOVELTY - The apparatus comprises a first lithographically-patternable substrate having a first planar surface, microscaled catalytic anode electrodes embedded on the first surface of the first substrate, a second lithographically-patternable substrate having a second planar surface opposite to the first surface, microscaled catalytic cathode electrodes embedded on the second surface of the second substrate, a counter electrode in proximity to but not on the surface, pore connecting the first and second surfaces, a unit for collecting evolved hydrogen and/or oxygen gas, and an electrical powering unit.    USE - The apparatus e.g. electrolyzer is useful for electrolytic splitting of water into hydrogen and/or oxygen, where the hydrogen gas is useful as a fuel source for industrial applications and the hydrogen and oxygen gases are useful for a Fischer-Tropsch, Haber process or petroleum refining process.    ADVANTAGE - The apparatus ensures rapid electrolytic splitting of water thus efficiently and cost-effectively producing large amounts of hydrogen and oxygen with high purity and without generation of toxic and environmentally unfriendly byproducts.    DETAILED DESCRIPTION - The apparatus comprises a first lithographically-patternable substrate having a first planar surface, microscaled catalytic anode electrodes embedded on the first surface of the first substrate, a second lithographically-patternable substrate having a second planar surface opposite to the first surface, microscaled catalytic cathode electrodes embedded on the second surface of the second substrate, a counter electrode in proximity to but not on the surface, pore connecting the first and second surfaces, a unit for collecting evolved hydrogen and/or oxygen gas, an electrical powering unit for applying a voltage across the microscaled catalytic anode and cathode electrodes and the counter electrode, a container for holding an aqueous electrolyte and housing the microscaled catalytic anode and cathode electrodes and the counter electrode, a first compartment that surrounds the microscaled catalytic anode electrodes while excluding the microscaled catalytic cathode electrodes, a second compartment that surrounds the microscaled catalytic cathode electrodes while excluding the microscaled catalytic anode electrodes, and a proton exchange membrane having first and second planar surfaces. The counter electrode comprises: a catalytic cathode electrode if the microscaled catalytic electrodes are catalytic anode electrodes or a catalytic anode electrode if the microscaled catalytic electrodes are catalytic cathode electrodes; and microscaled catalytic counter electrodes embedded on a separate lithographically-patternable substrate. The lithographically-patternable substrate is a rigid planar semiconducting substrate that is a silicon- containing substrate and made of a semiconducting composition, and possesses a first surface on which is disposed microscaled catalytic anode electrodes, and a second surface on which is disposed microscaled catalytic cathode electrodes. The collecting unit comprises a canopy trapping device positioned over the microscaled catalytic electrodes, and a separate canopy trapping device positioned over the microscaled catalytic counter electrodes. The microscaled catalytic anode and cathode electrodes and the counter electrode are separated by an ion-permeable barrier between the microscaled catalytic anode and cathode electrodes and the counter electrode, and are housed in the separate compartments provided that unit is included for allowing ions to migrant between the compartments. The separate compartments are adjoined by a common wall (6) that includes a pore that traverses the common wall. The common wall is comprised of the lithographically-patternable substrate having the microscaled catalytic electrodes. The first surface of the substrate faces into a first compartment in which oxygen is to be produced. The second surface of the substrate faces into a second compartment in which hydrogen is to be produced. The electrical powering unit includes: electrically-conductive bond pads and wiring connected to the electrodes; a receiving coil in electrical communication with the microscaled catalytic electrodes; a rectenna; a circuitry for monitoring voltage and current levels of each microscaled catalytic electrode; a circuitry for setting voltage and current levels of each microscaled catalytic electrode; and superconducting wires for bringing electric current to the microscaled catalytic electrodes. The receiving coil includes a unit for producing electrical power wirelessly from a wireless transmission source. The microscaled catalytic electrodes and electrical powering unit are lithographically patterned onto the lithographically-patternable substrate. The lithographically-patternable substrate is hermetically sealed provided that electrocatalytic surfaces of the microscaled catalytic electrodes are exposed. The proton exchange membrane is sandwiched between the first and second rigid planar substrates. The first planar surface of the membrane is present in physical contact with the second planar surface of the first rigid planar substrate. The second planar surface of the membrane is present in physical contact with the second planar surface of the second rigid planar substrate. The pore has a first section and a second section. The first and second pore sections are colinear. The first section extends from the membrane to the first planar surface of the first rigid planar substrate. The second pore section extends from the membrane to the first planar surface of the second rigid planar substrate. The catalytic anode and cathode electrode contains microscopic catalytic hot spots, and an insulating layer containing microscopic holes. The holes permit the catalytic electrode to be exposed to electrolyte only at the holes. INDEPENDENT CLAIMS are included for:    (1) an electrode device; and    (2) a method for producing hydrogen and oxygen gases from the electrolytic splitting of water and for producing chlorine gas and/or a metal hydroxide by a chloralkali process.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a water electrolysis device.    Hydrogen production compartment (2)    Oxygen production compartment (4)    Common wall (6)    Wafer electrode assembly (8)    Transmission coil. (10)