DEVICE FOR SOLAR LIGHT DRIVEN CO2 REDUCTION IN WATER
Method and photo-electrochemical system using Cu(In,Ga)Se 2 CIGS for reducing electrochemically CO 2 into CO using as catalyst a metal complex with quaterpyridine ligand, the electrochemical cell comprising a cathode, an anode, a cathodic electrolyte comprising water as the solvent, and a power supply providing the energy necessary to trigger the electrochemical reactions.
1 . A photo-electrochemical system to reduce CO 2 into CO, comprising an electrochemical cell with:
an anodic compartment with:
an anode with a current collector,
an anodic electrolyte solution comprising a solvent, and an anodic supporting electrolyte, the solvent being water;
a cathodic compartment with:
a cathodic electrolyte solution comprising the solvent, and a cathodic supporting electrolyte, the solvent being water,
a channel for flowing the reagent gas CO 2 into the cathodic electrolyte solution,
a photo-electrocatalytic electrode comprising a multilayer structure composed of:
a photovoltaic cell in charge of absorbing light and providing the energy necessary to trigger the photoelectrochemical reactions involving the reagent, which comprises:
a support layer,
a conductive layer, in contact with the support layer and connected to the anode through a wire,
a first layer of Cu(In x ,Ga y )Se 2 CIGS or an alloy of Cu(In x ,Ga y )Se w S z ;
in contact with the conductive layer, x being comprised in between 0 and 1, and y=1-x and w comprised in between 0 and 2 with z=2-w;
a second layer having material selected in the group comprising CdS, ZnS, in contact with the first layer,
the first and the second layer forming the photovoltaic junction to generate electrons,
a protecting layer, in contact with the second layer, which presents one or several metallic oxide layers,
a final molecular layer which is a molecular catalyst grafted onto the surface of the protecting layer to electrochemically reduce CO 2 into CO, located at the end of the multilayer and in contact with the cathodic electrolyte solution.
2 . The photo-electrochemical system according to claim 1 , wherein the molecular catalyst being chosen between the list:
metal porphyrin with one or several +N(C 1 -C 4 akyl) 3 groups, with the metal chosen among: Iron, Cobalt;
metal phthalocyanine, with the metal chosen among: Ion, Cobalt;
metal phthalocyanine with the metal chosen among: Ion, Cobalt, with one or several groups among: +N(C 1 -C 4 akyl) 3 , F, C(CH 3 ) 3 , or
cobalt quaterpyridine.
3 . The photo-electrochemical system according to claim 1 , wherein the molecular catalyst is a cobalt complex with the planar tetradentate ligand 2,2′:6′,2″:6″,2″′-quaterpyridine (Co-qPyH).
4 . The photo-electrochemical system according to claim 1 , wherein the molecular catalyst presents anchoring groups which are:
phosphonic acid,
alcoxysilane, or
hydroxamic acid,
to be grafted on the surface.
5 . The photo-electrochemical system according to claim 3 , wherein the structure of the cobalt complex with phosphoric acid (Co-qPyH) is as follows:
6 . The photo-electrochemical system according to claim 1 , wherein the protecting layer is selected in the group comprising T102, SrTiO 3 , SnO 2 , metal doped T102.
7 . The photo-electrochemical system according to claim 1 , wherein the conductive layer is connected to an additional source of potential in series.
8 . The photo-electrochemical system according to claim 1 , wherein the system comprises a layer selected in the group comprising: ZnO or AZO (aluminum doped zinc oxide), Indium Tin Oxide (ITO), between the layer having material selected in the group comprising CdS, ZnS, and the protecting layer.
9 . The photo-electrochemical system according to claim 1 , wherein the support layer is a chalcogenide film.
10 . The photo-electrochemical system according to claim 1 , wherein the conductive layer is a Mo layer.
11 . The photo-electrochemical system according to claim 1 , wherein the system presents:
the anodic compartment comprising:
on the current collector, at least a catalyst to electrochemically oxidize H 2 O to O 2 ,
the cathodic compartment comprising:
the multilayer photocatalytic electrode being a gas diffusion porous cathode which comprises, on a current cathode collector, the molecular catalyst incorporated in the porous cathode with a geometric surface S, to electrochemically reduce the gas comprising CO 2 into gaseous CO, with a by-production of gaseous H 2 , the cathode being a CIGS photovoltaic cell;
a channel for flowing the reagent gas CO 2 , at a controlled flow rate, onto or through the surface S of the gas diffusion porous current cathode collector;
a cathodic electrolyte solution inlet and a cathodic electrolyte solution outlet connected to the cathodic compartment, to circulate the cathodic electrolyte solution, and the remaining reagent gas CO 2 and the product gas CO by the outlet.
12 . The photo-electrochemical system according to claim 1 , wherein the final molecular layer being positioned facing the anode.
13 . The photo-electrochemical system according to claim 1 , wherein the pH of anodic electrolyte solution and the pH of cathodic electrolyte solution is between 4 to 14.
14 . Photo-electrochemical system to reduce CO 2 into CO, comprising an electrochemical cell with:
an anodic compartment with:
an anode with a current collector,
an anodic electrolyte solution comprising a solvent, and an anodic supporting electrolyte, the solvent being water;
a cathodic compartment with:
a cathodic electrolyte solution comprising the solvent, and a cathodic supporting electrolyte, the solvent being water,
a channel for flowing the reagent gas CO 2 into the electrolyte solution,
a cathode which comprises, a current collector which is connected in series with a photovoltaic cell in charge of absorbing light and providing the energy necessary to trigger the photoelectrochemical reactions involving the reagent,
the photovoltaic cell being situated outside the cathodic electrolyte and connected to the cathode through a wire,
the photovoltaic cell comprising:
a support layer,
a conductive layer connected to the anode through a wire, in contact with the support layer,
a first layer having material which is Cu(In x , Ga y )Se 2 CIGS or an alloy of Cu(In x , Ga y )Se w S z , x being comprised in between 0 and 1, and y=1-x and w comprised in between 0 and 2 with z=2-w,
a second layer having material selected in the group comprising: CdS, ZnS, in contact with the first layer, the first layer and the second layer forming the photovoltaic junction to generate electrons;
a third layer selected in the group comprising: ZnO or AZO (aluminum doped zinc oxide), Indium Tin Oxide (ITO), which is linked to the cathode,
the cathode having on the current collector a carbon-based gas diffusion electrode and a molecular catalyst to electrochemically reduce CO 2 into CO, which is:
grafted or deposited on the top of the carbon electrode, to be in the cathodic electrolyte, or
grafted or deposited on top of a metallic oxide layer.
15 . The photo-electrochemical system according to claim 14 , wherein the molecular catalyst being chosen between the list:
metal porphyrin with one or several +N(C 1 -C 4 akyl) 3 groups, with the metal chosen among: Iron, Cobalt;
metal phthalocyanine, with the metal chosen among: Iron, Cobalt;
metal phthalocyanine with the metal chosen among: Iron, Cobalt, with one or several groups among: +N(C 1 -C 4 akyl) 3 , F, C(CH 3 ) 3 , or
cobalt quater pyridine.
16 . The photo-electrochemical system according to claim 14 , wherein the molecular catalyst is a cobalt complex with the planar tetradentate ligand 2,2′:6′,2″:6″,2″′-quaterpyridine (Co-qPyH).
17 . The photo-electrochemical system according to claim 14 , wherein the molecular catalyst is grafted on metallic oxide layer which is mesoporous T02 or SnO 2 or SrTiO 3 .
18 . The photo-electrochemical system according to claim 14 , wherein the support layer is a chalcogenide film.
19 . The photo-electrochemical system according to claim 14 , wherein the conductive layer is a Mo layer.
20 . The photo-electrochemical system according to claim 14 , wherein the conductive layer is connected to an additional source of potential in series.