The invention belongs to the technical field of
electrochemical engineering and relates to a method for controlling the
cathode potential in an electrochemical
hydrogen pump CO2 hydrogenation reactorby a film method. The method is characterized in that a positive charge-modified
proton exchange film is utilized in place of a liquid buffer layer, when
electric energy is applied to the electrochemical
hydrogen pump CO2 hydrogenation reactor,
hydrogen protons generated by
anode hydrogen dissociation pass through the positive charge-modified
proton exchange film, and in-situ adsorbed hydrogen generated at a
cathode undergoes
hydrogenation reaction with CO2; positive charges are introduced into the
proton exchange film through
ion displacement or layer-by-layer self-assembling, the positive charges in the film migrate and accumulate toward the
cathode under the action of an
electric field to form a double
electrode layer with the cathode, the cathode potential of CO2 hydrogenation is regulated, and CO2
hydrogenation reaction is promoted. The method is advantaged in that the modified film is utilized in place of the liquid buffer layer, the
liquid phase environment can be avoided, interface problems are eliminated, the higher cathode potential can be achieved, moreover, the Donnan repulsion effect of the positive charges to the hydrogen protons is utilized, the
hydrogen evolution reaction is stably inhibited for a long time, and relatively high CO2 hydrogenation efficiency is achieved.