Photovoltaic-electrochemical (pv-ec) system

Patent metadata

Field	Value
Publication number	US-2021115576-A1
Application number	US-201917046755-A
Country	US
Kind code	A1
Filing date	Apr 16, 2019
Priority date	Apr 17, 2018
Publication date	Apr 22, 2021
Grant date	—

Abstract

The present disclosure relates to a method of operating an integrated photovoltaic-electrochemical (PV-EC) system, a method for an in situ and continuous removal of byproducts generated and absorbed on the surface of the PV-EC system and the PV-EC system which is able to regenerate its activity in a continuously operable manner

First claim

1 .- 14 . (canceled)

15 . A method of operating an integrated photovoltaic-electrochemical (PV-EC) system comprising a photovoltaic system (PV) that generates a voltage under irradiation, and at least one electrochemical cell (EC), the at least one electrochemical cell comprising:
i) a cathodic compartment which comprises a cathodic material which acts as a cathode electrode and a catholyte, the cathodic material being a conductive electrode with immobilized CO 2 reduction electrocatalyst material thereon; ii) an anodic compartment which comprises an anodic material which acts as an anode electrode and an anolyte; and iii) an ion-exchange membrane disposed between the cathodic compartment and the anodic compartment; the photovoltaic system being electrically connected to the anode and cathode electrodes of the at least one electrochemical cell for providing a voltage to the at least one electrochemical cell; wherein the electrical connections between the photovoltaic system and the anode and cathode electrodes of the electrochemical cell are configured to alternate, in the form of pulses of opposite voltage, a first and a second mode of operation; wherein the PV-electrode junctions are shielded from the electrolyte; the method comprises: removing the byproduct species generated and absorbed on the surface of the cathodic material of the integrated photovoltaic-electrochemical (PV-EC) system operating to conduct the electrochemical reduction of CO 2 , by alternating, in the form of pulses of opposite polarity voltage, a first and a second mode of operation, wherein a) the first mode of operation, direct EC operation mode, comprises providing, by the photovoltaic system, a first negative voltage to the at least one electrochemical cell, for a first period of time, in order to conduct the electrochemical reduction of CO 2 ; and b) the second mode of operation, reverse EC operation mode, comprises providing, by the photovoltaic system, a second voltage to the at least one electrochemical cell, with opposite polarity to that of the direct mode, for a second period of time, in order to conduct the desorption and the consequent removal of the byproduct species generated and adsorbed onto the surface of the cathodic material during the direct EC operation mode; being the amplitude of such a second voltage of opposite polarity at least the minimum necessary to desorb the byproduct species generated and adsorbed during the direct EC operation mode; wherein the method takes place in situ and in a continuous mode; wherein the photovoltaic PV system and the electrochemical EC device are combined together in a single device, and wherein the electrolyte is flowing through the system decreasing the temperature of the system.

16 . The method according to claim 15 , wherein the voltage pulses of opposite polarity are supplied for a pulse duration resulting in a duty-cycle comprised from 99.9 to 65%.

17 . The method according to claim 15 , wherein the total cell voltage amplitude during the reverse EC operation mode is comprised from 1.5V to 5V.

18 . The method according to claim 15 , wherein the anodic material is a conductive material with an oxygen evolution reaction (OER) electrocatalyst.

19 . The method according to claim 15 , wherein the immobilized CO 2 reduction electrocatalyst material of the cathodic material is selected from:
a) a metal with a high overpotential to hydrogen evolution, low CO adsorption and high overpotential for CO 2 to CO 2 radical ion, selected from the group consisting of Pb, Hg, In, Sn, Cd, TI and Bi; b) a metal with a medium overpotential to hydrogen evolution and low CO adsorption, selected from the group consisting of Au, Ag, Zn, Pd and Ga; c) a metal with a high CO adsorption and a medium overpotential to hydrogen evolution, which is Cu; d) a metal with a relatively low overpotential to hydrogen evolution and a high CO adsorption, selected from the group consisting of Ni, Fe, Pt, Ti, V, Cr, Mn, Co, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, Re, and Ir; e) an oxide of any of the metals of a), b), c) or d) type; and f) combinations thereof.

20 . The method according to claim 15 , wherein the immobilized CO 2 reduction electrocatalyst material of the cathodic material is selected from the group consisting of Au, Ag, Zn, Pd, Ga, Ni, Fe, Pt, Ti, Ru, Cu, an oxide of any of these metals and combinations thereof, the materials being deposited on a conductor support.

21 . The method according to claim 20 , wherein the conductor support is a highly porous and conductor support selected from carbon paper, carbon based nanofibres, metallic meshes, and metal foams.

22 . The method according to claim 15 , wherein the integrated photovoltaic-electrochemical system operates in a bias-free mode.

23 . The method according to claim 15 , wherein the byproduct species generated and adsorbed on the surface of the cathodic material during the direct EC operation mode are selected from CO and metal carboniles.

24 . An integrated photovoltaic-electrochemical (PV-EC) system comprising a photovoltaic (PV) system that generates voltage under irradiation and at least one electrochemical cell (EC);
the at least one electrochemical cell comprising: i) a cathodic compartment which comprises a cathodic material which acts as a cathode electrode and a catholyte, the cathodic material being a conductive electrode with immobilized CO 2 reduction electrocatalyst material thereon; ii) an anodic compartment which comprises an anodic material which acts as a anode electrode and an anolyte; and iii) an ion-exchange membrane disposed between the cathodic compartment and the anodic compartment; the photovoltaic system being electrically connected to the anode and cathode electrodes of the at least one electrochemical cell for providing a voltage to the at least one electrochemical cell; wherein the PV-electrode junctions are shielded from the electrolyte; wherein the electrolyte flows through the system decreasing the temperature of the system; and wherein the electrical connections between the photovoltaic system and the anode and cathode electrodes of the electrochemical cell are configured to alternate in the form of pulses of opposite voltage a first and a second mode of operation.

25 . The integrated photovoltaic-electrochemical (PV-EC) system according to claim 24 , wherein the anodic material is a conductive material with an oxygen evolution reaction (OER) electrocatalyst.

26 . The integrated photovoltaic-electrochemical (PV-EC) system according to claim 24 , wherein
a) the cathodic compartment further comprising a cathode support frame comprising the cathodic material, at least one distribution frame, and one or more sealing gaskets; b) the anodic compartment further comprising an anode support frame comprising the anodic material, at least one distribution frame, and one or more sealing gaskets; and wherein the fluid distribution frames and sealing gaskets, are arranged such that in use they allow introducing a catholyte or anolyte into the cathodic or anodic compartment through an inlet port and they allow exiting the catholyte or anolyte, respectively, and the products jointly through an outlet port; and wherein in use, the photovoltaic system provides pulses of opposite polarity to the electrodes such that the cathode autoregenerates its catalytic activity.

Assignees

• Repsol Sa
• Enagas Services Solutions S L U

Inventors

• Hernández Alonso María Dolores
• Penelas Pérez Germán
• Carretero González Nina Magali
• Andreu Arbella Teresa
• Morante Lleonart Juan Ramón

Classifications

• C25B13/00

  Diaphragms; Spacing elements · CPC title

• C25B15/00 Primary

  Operating or servicing cells · CPC title

• Y02P20/133

  Renewable energy sources, e.g. sunlight · CPC title

• C25B11/073

  characterised by the electrocatalyst material · CPC title

• Y02E10/50

  Photovoltaic [PV] energy · CPC title