Photoelectrochemical Capture of Acid Gases (Solar-Driven Carbon Dioxide Capture)

Systems and methods for redox-driven gas separation, such as via photoelectrochemical capture of acid gases, are generally described. What is described herein is a method, apparatus, and system for the photoelectrochemical capture of acid gases from a fluid gas mixture, as well as the photoelectrochemical release of the captured acid gas into a concentrated stream of the acid gas. Acid gases of industrial relevance can include carbon dioxide (CO2), various sulphur or nitrogen oxides (SOx, NOx), or hydrogen sulfide (HS). Certain embodiments are related to photoelectrochemical systems comprising a photoelectrode which, upon illumination with light, induces oxidation or reduction of redox-active species in an electrolyte solution in the system, that, when brought into contact with a fluid gas mixture including an acid gas, capture acid gases from the fluid gas mixture by raising the pH of the electrolyte solution or chemically binding to the acid gas molecule. The methods, apparatuses, and systems described herein are useful in carbon capture and pollution mitigation applications, and in direct use of solar energy to drive the capture and release of acid gases from fluid gas mixtures.