Gas fixation solar cell using gas diffusion semiconductor electrode

A process for gaseous photofixation comprising the steps:

• passing a gas through a hydrophobic gas diffusion region on one side of a porous matrix diffusion layer of a gas diffusion photosensitive electrode and contacting a semiconductor material supported by the other side of said porous matrix diffusion layer;
• passing illumination through an opposing light passing counterelectrode and a liquid electrolyte in contact with said counterelectrode and said electrode to illuminate said semiconductor producing a shift in the potential of the semiconductor causing an electrode photocurrent, said electrode photocurrent causing fixation of said gas by reduction of the gas with a p-type semiconductor at the semiconductor-electrolyte interface with concomitant oxidation of the electrolyte at the counterelectrode or oxidation of the gas with an n-type semiconductor at the semiconductor-electrolyte interface with concomitant reduction of the electrolyte at the counterelectrode;
• providing ionic conductance between the electrode and counterelectrode by a flowing liquid electrolyte in contact with said electrode and counterelectrode, the anolyte and catholyte portions of the electrolyte being chemically separated by a light passing and ionic conducting separator;
• providing removal of the fixed gas from and supply of electroactive electrolyte to said electrode by said flowing electrolyte;
• and
• passing electrons through an external electronic circuit for completion of the electronic circuit.

A process for molecular gas photo-reduction comprising the steps:

• passing molecular gas to be reduced through a hydrophobic gas diffusion region on one side of a porous matrix diffusion layer of a gas diffusion photosensitive cathode and contacting a p-type semiconductor supported by the other side of said porous matrix diffusion layer;
• passing illumination through an opposing light passing anode and a liquid electrolyte in contact with said anode and said cathode to illuminate said p-type semiconductor producing a positive shift in the potential of the semiconductor causing a cathodic photocurrent, said cathodic photocurrent causing reduction of the molecular gas to a fixed state at the semiconductor-electrolyte interface with concomitant oxidation of the electrolyte at the anode;
• providing ionic conductance between the cathode and anode by a flowing liquid electrolyte in contact with said cathode and anode, the anolyte and catholyte portions of the electrolyte being chemically separated by a light passing and ionic conducting separator;
• providing removal of the formed fixed material from and supply of electroactive electrolyte to said cathode by said flowing electrolyte;
• and
• passing electrons produced by oxidation of said electrolyte at said anode through an external electronic circuit to said cathode for completion of the electronic circuit, said external electronic circuit providing a bias voltage to said cathode from an external power source.

A process for fuel gas photo oxidation comprising the steps:

• passing fuel gas selected from the group consisting of methane, butane, propane, carbon monoxide and ammonia to be oxidized through a hydrophobic gas diffusion region on one side of a porous matrix diffusion layer of a gas diffusion photosensitive anode and contacting an n-type semiconductor supported by the other side of said porous matrix diffusion layer;
• illuminating said n-type semiconductor producing a negative shift in the potential of the semiconductor causing an anodic photocurrent, said anodic photocurrent causing oxidation of said fuel gas at the semiconductor-electrolyte interface with concomitant reduction at a gas diffusion oxygen/air cathode;
• providing ionic conductance between the cathode and anode by a liquid electrolyte in contact with said cathode and anode;
• and
• withdrawing electrical energy in an external circuit between the electrodes.