In Situ Catalyst Deposition for Liquid Alkaline Impure Water Electrolysis

Successful deployment of water-splitting technologies to produce green hydrogen holds the potential to enable large-scale renewable energy storage on the grid and help decarbonize the chemical industry. Currently, every commercial green hydrogen technology uses pure water as the feedstock, which adds to the costs and energy requirements of these systems. If innovative technologies can be developed to provide durable and high-e?ciency impure water-splitting, it would accelerate green hydrogen applications, especially in water-stressed areas. A proprietary process to coat and regenerate electrodes with high-performance electrocatalysts for liquid alkaline electrolyzers using pure water is under development. The technology allows for the deposition of catalysts, in situ, without shutting down or disassembling the electrolyzer stack. This enables the regeneration of catalysts in the field or operation in self-healing configurations. With suitable modifications, this technology has the potential to be applied to impure water electrolysis, where stack lifetimes are expected to be much shorter when using traditional catalyst technology. In this Phase I proposal, the strategy is to use impure water as the feedstock for creating liquid alkaline electrolyte (e.g., 30 wt% KOH) in conjunction with proprietary existing electrocatalysts and in situ coating technologies to enable highly e?cient and stable impure water electrolysis. The successful long-term operation of water electrolyzers in impure water requires a method to continually regenerate the hydrogen evolution catalyst without disassembling the electrolyzer stack. The existing proprietary catalyst regeneration technology, developed for use with pure water, provides an ideal starting point for developing in situ catalyst regeneration techniques for impure water operation. For Phase II, a wide range of electrolyzer test beds are available, including multiple 5-watt single-cell flow-through devices, as well as 200 W multi-cell test stacks which are currently under development. In addition, there is one 10 kW 40-cell stack in-house and two more kW-scale electrolyzers are currently being procured. Thus, if the demonstration of the feasibility of the in-situ catalyst coating technology with impure water in Phase I is successful, the team is well-equipped to test the technology at larger scales during Phase II and beyond.