MEMBRANE ELECTRODE ASSEMBLY WITH ENHANCED START-UP AND SHUT-DOWN DURABILITY
A membrane electrode assembly (MEA) includes a membrane, a cathode catalyst layer, a cathode co-catalyst layer including a hydrogen reservoir, an anode catalyst layer, and an anode co-catalyst layer including a hydrogen reservoir. The anode co-catalyst layer and the cathode co-catalyst layer cap a cathode potential at lower than 1.5V and an anode potential at lower than 1.0V. The anode co-catalyst layer and the cathode co-catalyst layer can include a platinum doped rare earth oxide, such as platinum doped cerium oxide.
1 . A membrane electrode assembly, comprising:
a proton exchange membrane disposed between two electrode layers, wherein one of the electrode layers includes a catalyst including a noble metal; and
a co-catalyst including a noble metal doped rare-earth oxide.
2 . The membrane electrode assembly of claim 1 , wherein the noble metal doped rare-earth oxide includes platinum doped cerium oxide.
3 . The membrane electrode assembly of claim 1 , wherein the noble metal doped rare-earth oxide is provided as a layer adjacent one of the electrode layers.
4 . The membrane electrode assembly of claim 1 , wherein the noble metal doped rare-earth oxide is integrated into one of the electrode layers.
5 . The membrane electrode assembly of claim 1 , wherein the two electrode layers include an anode layer and a cathode layer, the noble metal doped rare-earth oxide is integrated into the anode layer, integrated into the cathode layer, or is provided as a separate co-catalyst layer with the anode layer or the cathode layer.
6 . The membrane electrode assembly of claim 1 , wherein the noble metal is disposed on a carbon support and the noble metal includes platinum.
7 . The membrane electrode assembly of claim 6 , wherein one of the electrode layers includes the noble metal doped rare-earth oxide disposed on the carbon support.
8 . The membrane electrode assembly of claim 7 , wherein the carbon support is in a form of particles.
9 . The membrane electrode assembly of claim 8 , wherein the catalyst and the noble metal doped rare-earth oxide are disposed on different particles.
10 . The membrane electrode assembly of claim 8 , wherein the catalyst and the noble metal doped rare-earth oxide are disposed on same particles.
11 . The membrane electrode assembly of claim 1 , wherein each electrode layer includes an ionomer.
12 . The membrane electrode assembly of claim 11 , wherein the ionomer is configured to allow a proton to travel through the electrode layers.
13 . The membrane electrode assembly of claim 1 , wherein:
the electrode layers include an anode layer and a cathode layer, the anode layer including a catalyst including platinum disposed on a carbon support;
the noble metal doped rare-earth oxide includes platinum doped cerium oxide; and
the noble metal doped rare-earth oxide is provided as a layer adjacent the anode layer or the noble metal doped rare-earth oxide is integrated into the anode layer.
14 . The membrane electrode assembly of claim 13 , wherein the noble metal doped rare-earth oxide is integrated into the anode layer, the carbon support is in a form of particles, and the catalyst and the noble metal doped rare-earth oxide are disposed on same particles.
15 . The membrane electrode assembly of claim 13 , wherein the noble metal doped rare-earth oxide is integrated into the anode layer, the carbon support is in a form of particles, and the catalyst and the noble metal doped rare-earth oxide are disposed on different particles.
16 . A fuel cell comprising a membrane electrode assembly according to claim 1 .
17 . A fuel stack comprising a fuel cell including a membrane electrode assembly according to claim 1 .
18 . A vehicle comprising a fuel cell including a membrane electrode assembly according to claim 1 .
19 . A method of operating a fuel cell, the method comprising:
providing the fuel cell including a membrane electrode assembly, the membrane electrode assembly including:
a proton exchange membrane disposed between two electrode layers, wherein one of the electrode layers includes a catalyst including a noble metal; and
a co-catalyst including a noble metal doped rare-earth oxide; and
switching the fuel cell from one of a start-up state and a shut-down state to the other of the start-up state and the shut-down state, wherein the noble metal doped rare-earth oxide provides a reservoir of hydrogen.
20 . The method of claim 19 , wherein:
the electrode layers include an anode layer and a cathode layer, the anode layer including a catalyst including platinum disposed on a carbon support;
the noble metal doped rare-earth oxide includes platinum doped cerium oxide; and
the noble metal doped rare-earth oxide is provided as a layer adjacent the anode layer or the noble metal doped rare-earth oxide is integrated into the anode layer.