2025 AIChE Annual Meeting
Low-Cost Automation of Electrocatalyst Spray-Coating Using a Programmable Robotic Stage
Heterogeneous electrocatalysis is an emerging platform for producing valuable industrial compounds, such as oxirane and propylene oxide, efficiently and sustainably. However, the reproducibility and reliability of electrochemical data depend on the consistency of electrode preparation in the lab. A common method—manually spraying an aerosolized suspension of catalytic nanoparticles and ionomers onto a support with a pneumatic gun—suffers from limited reproducibility, as even minor hand variations can lead to uneven coating and alter catalyst loading by several milligrams, undermining data reliability. Furthermore, this method risks exposure to airborne nanoparticles and hazardous fumes.
To address these faults, we designed and built the Catalytic Aerosol Deposition Robot for Electrode Assembly (CADREA), a programmable translational stage equipped with two micrometer-level precision stepper motors, an ergonomic magnetically-centered electrode mount, passive and active fume ventilation capabilities, and a protective enclosure to enhance safety. Constructed for under 10% the cost of many commercial spray coaters, CADREA enables precise, repeatable motion to consistently automate electrode coating, even with an inexpensive airbrush nozzle.
Using a Pt/Pd suspension and a Ni foam support as a test case, we tuned stage movement speed, path geometry, jet range distance, and propellant gas pressure, ultimately reducing the standard deviation in catalyst mass per unit area from ±30.1% (manual application) to ±4.2% (robotic application). To improve reproducibility even further, we plan to continuously agitate the catalyst reservoir to prevent sedimentation, and demonstrate electrochemical consistency using chronoamperometry. However, the current gravimetric results demonstrate that CADREA is a low-cost, high-precision solution for scalable, reproducible in situ electrode fabrication.