Oxygen electrode catalytic layer for reversible, alkaline or anion exchange membrane electrochemical devices

A method of preparing a reversible, alkaline or anion exchange membrane (AEM) electrochemical device that is operable both as a fuel cell with the oxygen electrode supporting an oxygen reduction reaction (ORR) as a cathode of the fuel cell, and as an electrolyzer with the oxygen electrode supporting an oxygen evolution reaction (OER) as an anode of the electrolyzer, the method comprising:

• preparing an oxygen electrode by:
• blending an ORR catalyst comprising at least one platinum group metal (PGM) and an OER catalyst comprising nickel iron layered double hydroxide (NiFeLDH) particles, the blend being devoid of elemental carbon, and
• depositing the blend on a substrate layer that is devoid of elemental carbon to form the oxygen electrode,
• wherein said oxygen electrode is operable in an alkaline environment having a pH of 12 or more to evolve oxygen in an OER reduce oxygen gas in an ORR after repeated cycles of operation as a fuel cell and an electrolyzer;
• and
• constructing the device with the oxygen electrode and an electrode supporting a hydrogen oxidation reaction (HOR) when the device is operated as the fuel cell, and supporting the hydrogen evolution reaction (HER) when the device is operated as the electrolyzer, and a strongly alkaline electrolyte contacting the electrodes.

An alkaline or anion exchange membrane (AEM) electrolyzer comprising:

• an oxygen electrode comprising:
• a substrate layer that is devoid of elemental carbon, and
• a catalyst layer deposited on the substrate layer, the catalyst layer comprising a an oxygen evolution reaction (OER) catalyst comprising nickel iron layered double hydroxide (NiFeLDH) particles, wherein the catalyst layer is devoid of elemental carbon;
• wherein the oxygen electrode is operable in an alkaline environment having a pH of 12 or more as an anode to evolve oxygen in the OER over repeated cycles of operation, and
• an electrode supporting a hydrogen evolution reaction (HER),
• wherein the electrodes contact a strongly alkaline electrolyte.