Redox mediated electrochemical reaction of a gas

A system comprising:

• a reaction chamber;
• a device for supplying a reactant gas to the reaction chamber;
• an electrochemical cell comprising first and second half-cells each comprising an electrode;
• at least one pump, and connections between the pump, the reaction chamber and the first half-cell providing a first flow circuit for the pump to circulate a liquid through the reaction chamber, from the reaction chamber to the first half-cell, through the first half-cell and back to the reaction chamber;
• wherein:
• the first half-cell defines a flow path to carry flow of the liquid into contact with the electrode;
• the reaction chamber defines flow paths to carry flow of the liquid and flow of the gas into contact with each other in the reaction chamber;
• an electrochemically reactive mediator substance is dissolved in the liquid and the mediator substance is such that when electric current is supplied to the electrode while the pump is circulating the liquid, the mediator substance is converted from a first state to a second state at the electrode;
• the gas is able to undergo a reaction with the mediator substance in the reaction chamber which converts the gas to a reaction product and returns the mediator substance to the first state thereof;
• and further wherein the liquid further comprises a solute enabling the liquid to display elastic turbulence;
• and
• the flow path in the reaction chamber is configured to compel changes in the direction of liquid flow, to cause elastic turbulence of the flow of the liquid in the reaction chamber.