PROCESS OF PATCH COATING OF CATALYST LAYERS USING MASK

Description

BACKGROUND

Catalyst coating is one step in the manufacturing of catalyst coated membranes (CCMs) for electrolyzer, fuel cells, or battery applications. This step influences the morphology and performance of the CCMs. Direct catalyst coating (DCC) is an ideal technology for the fabrication of CCMs. This technology involves directly applying a catalyst layer onto the membrane surface through a coating process. Compared with indirect coating, such as decal transfer coating, DCC technology is highly efficient, low cost, and produces high quality CCMs.

Using DCC technology, a high quality, fully coated CCM (a wide strip of catalyst layer) can be fabricated using a roll-to-roll process. However, when a fully coated CCM was assembled in the stack, there was a large area with a catalyst coating outside the cell active area, resulting in a large amount of coated catalysts not being used.

Therefore, there is a need for improved catalyst coating methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D are an illustration of one embodiment of the method of the present invention.

FIG. 2 is a picture of a patch-coated PEM CCM-N66-PVC.

FIG. 3 is a picture of a patch-coated AEM CCM-N66.

FIG. 4 is a picture of a fully coated PEM CCM-F.

FIG. 5 is a graph of polarization curves of a water electrolysis cell comprising of (a) PEM CCM-N66-PVC; (b) PEM CCM-PLA; and (c) PEM CCM-F, respectively, at 80° C., atmospheric pressure.

DESCRIPTION

The present invention meets that need providing a method of selective area coating (patch coating) of a catalyst layer which matches the cell active area to improve utilization of the precious metal catalysts for CCM manufacturing. Patch coating (or intermittent coating) is coating in which the coating area is smaller than the total area of the membrane roll and defined by an uncoated border. For slot die patch coating of catalyst layers on a membrane, the shape is a square or a rectangle. Patch coating can be completed in full membrane web or lane coating, creating squares or rectangles downweb from the coating source.

Compared with a full coating process, patch coating offers significant advantages. First, patch coating applies the catalyst to the active testing area, which means less catalyst is used overall, leading to significant cost savings, especially when expensive catalysts like platinum group metals (PGM) are used. Second, a patch coated CCM leaves the sealing edges uncoated, thereby improving the integrity and reliability of the sealing and reduces the risk of leaks at the edges of the membrane, especially when the cells are operated under high pressure. Finally, patch coating allows for better compatibility with different stack designs, especially those that require precise control over compression and sealing. Without having a catalyst layer on the edges, it can be easier to adjust compression settings during assembly, ensuring optimal performance without damaging the CCM.

Several technologies have been used for roll-to-roll directly catalyst coating, including slot die coating, gravure coating, screen printing, and comma coating. However, only slot die coating with a specially designed coating head, gravure coating, and screen printing can be used for the coating of patch CCMs. Moreover, the slot die can only coat square or rectangular patches; it is difficult to coat a circle patch or a patch with curved corners. Gravure coating can coat different patch shapes, but it requires fabrication of expensive gravure cylinders with the desired patterns. Screen printing can coat different patches as well. However, this technology normally needs paste-like, highly viscous ink. In contrast, the present invention is a simple and low-cost technology which can be used for coating catalyst layers in all types of patches.

The present invention is a method for patch coating CCMs using a mask. An adhesive or non-adhesive polymer film is used as the mask. For the non-adhesive mask, a film with appropriate thickness, surface properties and a glass transition temperature (Tg) lower than the Tg of the membrane is used. To create a mask, the polymer film is cut into the desired patch shape and size. The mask is then assembled onto the membrane surface. For the non-adhesive mask, a hot press or lamination of the mask can be used to prepare the assembly. The membrane with the mask can be integrated with various coating methods to fabricate the CCM. After coating and drying, the mask is removed, leaving the patch CCM. This mask method can be applied to the fabrication of CCMs for anion exchange membranes (AEM), proton exchange membrane (PEM), and bipolar membranes for use in water electrolysis and fuel cells, and fabrication of electrodes for batteries.

The present method offers several advantages compared to other patch coating technologies. The mask is easy to prepare, assemble with the membrane, and remove after coating and drying. The mask method is cost effective, scalable and can be easily integrated with commonly used roll-to-roll coating techniques for patch coating of CCMs. It allows for the fabrication of CCMs in any patch shape and size. The mask is made from commercially available polymer films (adhesive or non-adhesive), making the technology cost-effective.

The fabrication of patch CCMs using the mask method typically involves the following steps. The mask is prepared by cutting films into the desired patch shapes and sizes using a precision cutting machine. Any suitable film can be used. The thickness of the film mask can be in a range of 5 μm to 100 μm, or in a range of 10 μm to 50 μm, or in a range of 10 μm to 30 μm. For non-adhesive low Tg films, the glass transition temperature is typically in the range of 30-150° C. Suitable polymers include, but are not limited to, nylon, polyvinyl chloride (PVC), high-density polyethylene (HDPE), polypropylene (PP), polylactic acid (PLA), and polyvinylidene fluoride (PVDF).

The film mask is placed onto the membrane and pressed at an appropriate temperature and pressure for a specified time using a heated platen press or hot roller press. The temperature for mask assembly is usually slightly higher than the Tg of the mask material. In some embodiments, the temperature for mask assembly is about 5-50° C. higher than the Tg of the mask material, or about 5-30° C. higher than the Tg of the mask material.

A backing layer may be attached the opposite side the membrane before applying the catalyst coating layer, if desired to stabilize the membrane during coating.

The first catalyst ink is applied to the membrane with the mask using common catalyst coating technologies such as Mayer rod coating, slot die coating, or comma coating. In some embodiments, the coating area is larger than the open area on the mask and the catalyst on the non-open mask area can be recovered. In some embodiments, to save catalyst material, the coating area is limited to cover only the open area on the mask. After coating, the two layer CCM (membrane and catalyst coating layer) is dried to solidify catalyst layer.

After drying, the mask is removed from the membrane surface, leaving the CCM with the desired patch on one side. The catalyst on the mask can be recycled to reduce the overall CCM costs.

To prepare a three-layer CCM (with both anode and cathode coated on the membrane), the first side of the membrane is coated using the mask method as described above. The backing layer on the membrane (if used) is removed. The mask for the second side is aligned with the catalyst coating layer on the first side and assembled onto the membrane using a hot press. The second catalyst ink is applied to the membrane with the second mask. After drying, the masks for both sides are removed.

Alternatively, the second catalyst coating layer may be applied using a different coating method.

For adhesive films, the polymeric film layer may have an adhesive layer on one side. Any suitable adhesive layer can be used, including, but not limited to, acrylic and silicone adhesives. Suitable polymers for the non-adhesive side of the adhesive films include, but are not limited to, nylon, PVC, HDPE, PP, PLA, PVDF, polyethylene-co-polypropylene, polyimide, polyetherimide, polyamide, polycarbonate, polyethylene terephthalate, poly(ether ether ketone), poly(methyl methacrylate), polyphenylene sulfone, polysulfone, polyethersulfone, polystyrene, poly(vinyl acetate), polychlorotrifluoroethylene, polytetrafluoroethylene, acrylonitrile butadiene styrene, or combinations thereof.

One aspect of the invention is a method of making a catalyst coated membrane comprising a patch coated catalyst layer. In one embodiment, the method comprises applying a first film mask having a first open area to a first side of a membrane. A first catalyst coating layer is applied to a surface of the mask and the open area on the first side of the membrane. The first catalyst coating layer is dried. The mask is removed forming the catalyst coated membrane comprising a first patch coated catalyst layer on the first side of the membrane.

In some embodiments, the method further comprises applying a second film mask having a second open area to a second side of the membrane; applying a second catalyst coating layer to a surface of the second film mask and the second open area on the second side of the membrane; drying the second catalyst coating layer; removing the second mask forming the catalyst coated membrane comprising the first patch coated catalyst layer on the first side of the membrane and a second patch coated catalyst layer on the second side of the membrane; and wherein the first patch coated catalyst layer and the second patch coated catalyst layer are coextensive.

In some embodiments, the method further comprises applying a backing layer to a second side of the membrane before applying the first mask, wherein the backing layer comprises a polymeric film comprising nylon, polyimide, polyetherimide, polyethylene, polypropylene, polyethylene-co-polypropylene, polyamide, poly(vinyl chloride), poly(vinyl alcohol), polycarbonate, polyimide, polylactic acid, polyethylene terephthalate, poly(ether ether ketone), poly(methyl methacrylate), polyphenylene sulfone, polysulfone, polyethersulfone, polystyrene, poly(vinyl acetate), polychlorotrifluoroethylene, polytetrafluoroethylene, acrylonitrile butadiene styrene, poly(vinylidene fluoride), or combinations thereof.

In some embodiments, the method further comprises removing the backing layer from the second side of the membrane before applying a second film mask having a second open area to a second side of the membrane.

In some embodiments, the method further comprises applying a second backing layer to the first side of the membrane after applying the second film mask and before applying a second catalyst coating layer to a surface of the second film mask and the second open area on the second side of the membrane.

In some embodiments, the method further comprises applying a second film mask having a second open area to a second side of the membrane after drying the first catalyst coating layer; applying a second catalyst coating layer to a surface of the second mask and the second open area on the second side of the membrane; and drying the second catalyst coating layer.

In some embodiments, the method further comprises removing the second mask forming the catalyst coated membrane comprising the first patch coated catalyst layer on the first side of the membrane and a second patch coated catalyst layer on the second side of the membrane;

and wherein the first patch coated catalyst layer and the second patch coated catalyst layer are coextensive. In some embodiments, the thickness of the first patch coated catalyst layer is in a range of 2 μm to 50 μm, or in a range of 2 μm to 20 μm, or in a range of 5 μm to 10 μm.

In some embodiments, the thickness of the second patch coated catalyst layer is in a range of 2 μm to 50 μm, or in a range of 2 μm to 20 μm, or in a range of 5 μm to 10 μm.

In some embodiments, the material for the first mask and the second mask are the same.

In some embodiments, the material for the first mask and the second mask are different.

In some embodiments, the first mask comprises a polymeric film layer with an adhesive layer on one surface of the film, and wherein the adhesive layer comprises an acrylic adhesive or a silicone adhesive.

In some embodiments, the first mask comprises a non-adhesive polymeric film having a glass transition temperature lower than a glass transition temperature of the membrane.

In some embodiments, the non-adhesive polymeric n film has a glass transition temperature in a range of 30-150° C.

In some embodiments, the non-adhesive polymeric film comprises nylon, polyamide, poly(vinyl chloride), poly(vinyl alcohol), polycarbonate, polyimide, polylactic acid, polyethylene terephthalate, poly(ether ether ketone), poly(methyl methacrylate), polyphenylene sulfone, poly sulfone, polyethersulfone, polystyrene, poly(vinyl acetate), polychlorotrifluoroethylene, polytetrafluoroethylene, acrylonitrile butadiene styrene, poly(vinylidene fluoride), or combinations thereof.

In some embodiments, applying the mask comprises applying heat or pressure or both to the mask.

In some embodiments, the method further comprises recovering the catalyst from the catalyst-coated mask after the mask is removed; and recycling the recovered catalyst.

In some embodiments, the mask has a plurality of open areas.

The open area of the mask may have any suitable shape. In some embodiments, the open area of the mask has the shape of a circle, a square, a square with rounded corners, a triangle, a triangle with rounded corners, a rectangle, or a rectangle with rounded corners.

In some embodiments, the mask surface is hydrophilic.

In some embodiments, the method further comprises applying a second catalyst coating to a second side of the catalyst coated membrane before applying the first catalyst coating layer or after applying the first catalyst coating layer.

In some embodiments, the catalyst coating is applied using Mayer rod coating, screen printing, blade coating, spray coating, dip coating, gravure coating, slot die coating, comma coating, or combinations thereof.

In some embodiments, the membrane is a proton exchange membrane, an anion exchange membrane, or a bipolar membrane, and wherein the membrane comprises a fluoropolymer, a non-fluoropolymer, or a combination of thereof.

Another aspect of the invention is a method of making a catalyst coated membrane comprising a patch coated catalyst layer. In one embodiment, the method comprises applying a backing layer to a second side of a membrane. A first film mask having a first open area is applied to a first side of the membrane. A first catalyst coating layer applied to a surface of the mask and the open area on the first side of the membrane. The first catalyst coating layer is dried. The backing layer is removed from the second side of the membrane. A second film mask having a second open area is applied to the second side of the membrane. A second catalyst coating layer is applied to a surface of the second film mask and the second open area on the second side of the membrane. The second catalyst coating layer is dried. The first and the second masks are removed forming the catalyst coated membrane comprising the first patch coated catalyst layer on the first side of the membrane and a second patch coated catalyst layer on the second side of the membrane, and wherein the first patch coated catalyst layer and the second patch coated catalyst layer are coextensive.

The method 100 is illustrated in FIGS. 1A-1D. A film mask 105 having an open area 110 is placed on a membrane 115, as shown in FIG. 1A. The mask 105 is positioned on the membrane 115 either by hot pressing a non-adhesive film or by using an adhesive film as shown in FIG. 1B. The catalyst coating layer 120 is applied to the mask 105 as shown in FIG. 1C. The mask 105 with the catalyst coating layer 120 is removed, resulting in the membrane 115 having a patch coated catalyst layer 125 on the surface, as shown in FIG. 1D.

The process could be repeated to form a patch coated catalyst layer on opposite side, if desired. Alternatively, a second catalyst coating layer could be applied to opposite side using another coating method, if desired.

EXAMPLES

The following examples are provided to illustrate one or more preferred embodiments of the invention but are not limited embodiments thereof. Numerous variations can be made to the following examples that lie within the scope of the invention.

Example 1

Preparation of a Patch-Coated 3-Layer PEM CCM Using Non-Adhesive Nylon 6,6 Film Mask and Polyvinyl Chloride (PVC) Film Masks (Abbreviated as PEM CCM-N66-PVC)

Non-adhesive low glass transition temperature (Tg) nylon 6,6 and polyvinyl chloride (PVC) polymer films were used as mask materials. One piece of nylon 6,6 film with 20 μm thickness and one piece of PVC film with 20 μm thickness were cut in the middle to form a square patch shape open area of 100 mm×100 mm using a cutting tool.

The nylon 6,6 film mask was placed on a first surface of a PEM membrane with a backing layer on a second surface of the membrane and pressed at 80° C. under 725 psig pressure for 10 min using a heated platen press. The membrane with the nylon 6,6 mask was taped on a glass plate, and the glass plate was placed on a Mayer rod coating machine. A first anode catalyst ink was applied to the first surface of the membrane with the nylon 6,6 mask using a Mayer rod. After coating, the glass plate with the catalyst coated membrane was dried in an oven at 60° C. for 30 min.

After drying and removing the backing layer on the second surface of the membrane, the PVC film mask was placed on the second surface of the PEM membrane and pressed at 90° C. under 100 psig pressure for 15 min using a heated platen press. The square open area of the PVC mask was aligned with the square patch coating area on the first anode catalyst coating side, so that first patch coated anode catalyst layer and the second open area of the PVC mask were coextensive. The membrane with the first anode catalyst coating on the surface of the nylon 6,6 mask and the open area and the PVC mask on the second surface was taped on a glass plate and the PVC mask faced up. The glass plate was then placed on the Mayer rod coating machine. A second cathode catalyst ink was applied to the surface of the membrane with the PVC mask using a Mayer rod. After coating, the glass plate with catalyst coated membrane was dried in an oven at 85° C. for 15 min.

After drying, the nylon 6,6 and PVC masks were removed from the surfaces of the membrane to form an anode/membrane/cathode 3-layer patch-coated PEM CCM with 100 mm×100 mm square coating area abbreviated as PEM CCM-N66-PVC as shown in FIG. 2.

Example 2

Preparation of a Patch-Coated 3-Layer PEM CCM Using Non-Adhesive Polylactic Acid (PLA) Film Masks (Abbreviated as PEM CCM-PLA)

A non-adhesive low glass transition temperature (Tg) polylactic acid (PLA) polymer film was used as the mask material. Two pieces of PLA films with 25 μm thickness were cut in the middle to form a square patch shape open area of 100 mm×100 mm using a cutting tool. The two PLA masks were used for the preparation of an anode/membrane/cathode 3-layer patch-coated PEM CCM with 100 mm×100 mm square coating area abbreviated as PEM CCM-PLA. The CCM coating process is the same as described in Example 1, but PLA masks were used instead of nylon 6,6 and PVC masks.

Example 3

Preparation of a Patch-Coated 2-Layer AEM CCM Using Non-adhesive Nylon 6,6 Film Masks (Abbreviated as AEM CCM-n66)

A piece of non-adhesive nylon 6,6 film with a thickness of 20 μm was cut in the middle form a circle patch shape open area with a circle diameter of 90 mm using a cutting tool. The nylon 6,6 film mask was placed on a first surface of a AEM membrane with a backing layer on a second surface of the membrane and pressed at 80° C. under 725 psig pressure for 10 min using a heated platen press. The membrane with the nylon 6,6 mask was taped on a glass plate, and the glass plate was placed on a Mayer rod coating machine. A first cathode catalyst ink was applied to the first surface of the membrane with the nylon 6,6 mask using a Mayer rod. After coating, the glass plate with the cathode catalyst coated membrane was dried in an oven at 60° C. for 30 min.

After drying, the nylon 6,6 mask was removed from the surface of the membrane to form a cathode/membrane 2-layer patch-coated AEM CCM with a 90 mm diameter circle coating area abbreviated as AEM CCM-N66 as shown in FIG. 3.

Example 4

Preparation of a Patch-Coated 3-Layer PEM CCM Using Adhesive Scotch Magic™ Tape Film Masks (Abbreviated as PEM CCM-SM)

Adhesive Scotch Magic™ tape (3M) was used as a mask material. The tape was applied to a first surface of a PEM membrane with a backing layer on a second surface of the membrane. A 95 mm×95 mm square open area was left uncovered by the tape for an anode catalyst coating.

The membrane with the adhesive Scotch Magic™ tape mask was taped on a glass plate with the mask side facing up. The glass plate was placed on a Mayer rod coating machine. The first anode catalyst ink was applied to the first surface of the membrane with the adhesive mask using a Mayer rod. After coating, the glass plate with the catalyst coated membrane was dried in an oven at 60° C. for 30 min. The adhesive mask was removed after drying.

After removing the backing layer on the second surface of the membrane, the adhesive Scotch Magic™ tape (3M) was applied to the second surface of the PEM membrane. A 95 mm×95 mm square open area aligned with the anode coated square area on the first surface of the membrane was left uncovered by the tape for cathode catalyst coating. The first patch coated anode catalyst layer and the second open area formed by the adhesive mask were coextensive. The membrane with the first anode catalyst coating and the adhesive mask on the second surface was taped on a glass plate and the adhesive mask faced up. The glass plate was then placed on the Mayer rod coating machine. A second cathode catalyst ink was applied to the surface of the membrane with the adhesive mask using a Mayer rod. After coating, the glass plate with catalyst coated membrane was dried in an oven at 60° C. for 30 min.

After drying, the adhesive mask was removed from the second surface of the membrane to form an anode/membrane/cathode 3-layer patch-coated PEM CCM with 95 mm×95 mm square coating area abbreviated as PEM CCM-SM.

Comparative Example 1

Preparation of a Fully Coated 3-Layer PEM CCM Using a Mayer Rod Coating Method Without Any Mask (Abbreviated as PEM CCM-F)

An anode/membrane/cathode 3-layer fully coated PEM CCM abbreviated as PEM CCM-F was prepared using a Mayer rod coating method without any mask.

A PEM membrane was taped on a glass plate and the glass plate was placed on a Mayer rod coating machine. A first anode catalyst ink was applied to the first surface of the membrane with a backing layer on the second surface of the membrane. After coating, the glass plate with the catalyst coated membrane was dried in an oven at 60° C. for 30 min.

The membrane with the anode catalyst coating on the first surface was taped on a glass plate and the second uncoated membrane surface faced up. The glass plate was then placed on the Mayer rod coating machine. A second cathode catalyst ink was applied to the second surface of the membrane using a Mayer rod. After coating, the glass plate with catalyst coated membrane was dried in an oven at 85° C. for 15 min to form an anode/membrane/cathode 3-layer fully coated PEM CCM abbreviated as PEM CCM-F as shown in FIG. 4.

Example 5

Evaluation of Water Electrolysis Performance of (a) PEM CCM-N66-PVC; (b) PEM CCM-PLA; and (c) PEM CCM-F, Respectively, at 80° C., Atmospheric Pressure

A PEM water electrolysis test station (Scribner 600 electrolyzer test system) was used to evaluate the water electrolysis performance of (a) PEM CCM-N66-PVC prepared in Example 1, (b) PEM CCM-PLA prepared in Example 2, and (c) PEM CCM-F prepared in Comparative Example 1, respectively, in a single electrolyzer cell. The test station included an integrated power supply, a potentiostat, an impedance analyzer for electrochemical impedance spectroscopy (EIS) and high-frequency resistance (HFR), and real-time sensors for product flow rate and cross-over monitoring. The CCM was sandwiched between a carbon paper (as a cathode PTL) and a Pt-Ti-felt (as an anode PTL). The testing was conducted at 80° C. and at atmospheric pressure. Ultrapure water was supplied to the anode of the CCM with a flow rate of 100 mL/min. The polarization curve was collected at 80° C., and the results are shown in FIG. 5.

It can be observed from the polarization curves in FIG. 5 that both patch-coated PEM CCM-N66-PVC (a) and PEM CCM-PLA (b) showed performance comparable to the fully coated PEM CCM-F (c), demonstrating the patch-coated PEM CCMs using the mask method showed high performance same as those CCM prepared without using any mask.

SPECIFIC EMBODIMENTS

While the following is described in conjunction with specific embodiments, it will be understood that this description is intended to illustrate and not limit the scope of the preceding description and the appended claims.

A first embodiment of the invention is a method of making a catalyst coated membrane comprising a patch coated catalyst layer comprising applying a first film mask having a first open area to a first side of a membrane; applying a first catalyst coating layer to a surface of the mask and the open area on the first side of the membrane; drying the first catalyst coating layer; and removing the mask forming the catalyst coated membrane comprising a first patch coated catalyst layer on the first side of the membrane. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising applying a second film mask having a second open area to a second side of the membrane; applying a second catalyst coating layer to a surface of the second film mask and the second open area on the second side of the membrane; drying the second catalyst coating layer; removing the second mask forming the catalyst coated membrane comprising the first patch coated catalyst layer on the first side of the membrane and a second patch coated catalyst layer on the second side of the membrane; and wherein the first patch coated catalyst layer and the second patch coated catalyst layer are coextensive. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the thicknesses of the first film mask and the second film mask are in a range of 5 μm to 100 μm, or in a range of 10 μm to 50 μm, or in a range of 10 μm to 30 μm. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising applying a backing layer to a second side of the membrane before applying the first mask, wherein the backing layer comprises a polymeric film comprising nylon, polyimide, polyetherimide, polyethylene, polypropylene, polyethylene-co-polypropylene, polyamide, poly(vinyl chloride), poly(vinyl alcohol), polycarbonate, polyimide, polylactic acid, polyethylene terephthalate, poly(ether ether ketone), poly(methyl methacrylate), polyphenylene sulfone, poly sulfone, polyethersulfone, polystyrene, poly(vinyl acetate), polychlorotrifluoroethylene, polytetrafluoroethylene, acrylonitrile butadiene styrene, poly(vinylidene fluoride), or combinations thereof. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising removing the backing layer from the second side of the membrane before applying a second film mask having a second open area to a second side of the membrane. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising applying a second backing layer to the first side of the membrane after applying the second film mask and before applying a second catalyst coating layer to a surface of the second film mask and the second open area on the second side of the membrane. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising applying a second film mask having a second open area to a second side of the membrane after drying the first catalyst coating layer; applying a second catalyst coating layer to a surface of the second mask and the second open area on the second side of the membrane; and drying the second catalyst coating layer. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising removing the second mask forming the catalyst coated membrane comprising the first patch coated catalyst layer on the first side of the membrane and a second patch coated catalyst layer on the second side of the membrane; and wherein the first patch coated catalyst layer and the second patch coated catalyst layer are coextensive. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the first mask comprises a polymeric film layer with an adhesive layer on one surface of the film, and wherein the adhesive layer comprises an acrylic adhesive or a silicone adhesive. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the first mask comprises a non-adhesive polymeric film having a glass transition temperature lower than a glass transition temperature of the membrane. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the non-adhesive polymeric film has a glass transition temperature in a range of 30-150° C. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the non-adhesive polymeric film comprises nylon, polyamide, poly(vinyl chloride), poly(vinyl alcohol), polycarbonate, polyimide, polylactic acid, polyethylene terephthalate, poly(ether ether ketone), poly(methyl methacrylate), polyphenylene sulfone, polysulfone, polyethersulfone, polystyrene, poly(vinyl acetate), poly chlorotrifluoroethylene, polytetrafluoroethylene, acrylonitrile butadiene styrene, poly(vinylidene fluoride), or combinations thereof. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein applying the mask comprises applying heat or pressure or both to the mask. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising recovering the catalyst from the catalyst-coated mask after the mask is removed; and recycling the recovered catalyst. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the mask has a plurality of open areas. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the open area of the mask has a shape of a circle, a square, a square with rounded corners, a triangle, a triangle with rounded corners, a rectangle, or a rectangle with rounded corners. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the mask surface is hydrophilic. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising applying a second catalyst coating to a second side of the catalyst coated membrane before applying the first catalyst coating layer or after applying the first catalyst coating layer. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the catalyst coating is applied using Mayer rod coating, screen printing, blade coating, spray coating, dip coating, gravure coating, slot die coating, comma coating, or combinations thereof. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the membrane is a proton exchange membrane, an anion exchange membrane, or a bipolar membrane, and wherein the membrane comprises a fluoropolymer, a non-fluoropolymer, or a combination thereof. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the thickness of the first patch coated catalyst layer is in a range of 2 μm to 50 μm, or in a range of 2 μm to 20 μm, or in a range of 5 μm to 10 μm, and wherein the thickness of the second patch coated catalyst layer is in a range of 2 μm to 50 μm, or in a range of 2 μm to 20 μm, or in a range of 5 μm to 10 μm.

A second embodiment of the invention is a method of making a catalyst coated membrane comprising a patch coated catalyst layer comprising applying a backing layer to a second side of a membrane; applying a first film mask having a first open area to a first side of the membrane; applying a first catalyst coating layer to a surface of the mask and the open area on the first side of the membrane; drying the first catalyst coating layer; removing the backing layer from the second side of the membrane; applying a second film mask having a second open area to the second side of the membrane; applying a second catalyst coating layer to a surface of the second film mask and the second open area on the second side of the membrane; drying the second catalyst coating layer; removing the first and the second masks forming the catalyst coated membrane comprising the first patch coated catalyst layer on the first side of the membrane and a second patch coated catalyst layer on the second side of the membrane; and wherein the first patch coated catalyst layer and the second patch coated catalyst layer are coextensive.

Without further elaboration, it is believed that using the preceding description that one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of this invention, without departing from the spirit and scope thereof, to make various changes and modifications of the invention and to adapt it to various usages and conditions. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limiting the remainder of the disclosure in any way whatsoever, and that it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

In the foregoing, all temperatures are set forth in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.