Rapid Electrocatalyst Discovery
Authors: Ivankin Andrey 
Published: September 2023

The transformation of the global economy to net-zero emissions requires shifting the energy mix away from fossil fuels toward zero-emissions electricity and energy sources such as hydrogen, decarbonizing industrial processes through electrification while increasing their energy efficiency, and utilizing the circular economy. Materials used today to catalyze these climate technologies are scarce, expensive, or simply not efficient enough for achieving the net-zero transition, demanding for new, more available, and better performing electrocatalysts. With the combinatorial explosion of electrocatalyst design possibilities when considering combinations of constituent elements, stoichiometry, size, shape, and structure, existing slow and serial in nature materials discovery technologies are unable to rationally find new disruptive electrocatalysts in a reasonable time frame.
Invented in the lab of Prof. Chad Mirkin at Northwestern University, and now being commercialized by Stoicheia, nanomaterial Megalibraries open the way for overcoming serendipity in materials discovery and accelerating commercialization of new electrochemical processes. Megalibraries are 4-square-centimeter chips with hundreds of millions of positionally encoded monodisperse polyelemental nanoparticles. By tuning Megalibrary synthesis parameters, the size and composition of nanoparticles can be gradually varied to yield tens of thousands of unique combinations that are replicated thousands of times to account for various structural configurations, each representing a catalyst candidate. Material diversity and complexity accessible through Megalibraries spans from early alkaline earth metals to platinum group metals to lanthanides, and arbitrary, yet precise combinations thereof. As such, Megalibraries provide a way to not only synthesize new electrocatalyst candidates at unprecedented speed but also access previously out-of-reach compositions and structures.
When coupled with high-throughput and spatially resolved screening technologies, Megalibraries unlock the power of combinatorial catalyst discovery like never before. Screening can be accomplished in a number of ways ranging from scanning droplet cell electrochemistry (SDC), which confines 3-electrode test cell into a microdroplet and is most similar to site-isolated rotating disc electrode (RDE) measurements, to microfluidics-based and optical methods to spectroscopy and electron microscopy. Measured electrocatalytic performance and structural characteristics can be correlated to the composition and size of positionally encoded nanoparticles, yielding the largest and most robust structure-function experimental database for electrocatalysis that can be used to train predictive machine learning algorithms for further acceleration of the discovery process.
By tuning operando measurement conditions to mimic end-use operating environment, we increase translatability of on-chip electrocatalyst discoveries to real-world systems, thereby condensing R&D efforts for bringing new electrocatalysts and electrocatalyst-driven solutions to market. Megalibrary platform is poised to play an important role in the electrification of chemical and energy industries but delivering new superior electrocatalysts for applications spanning from low-temperature water electrolysis to metal-air batteries to sustainable chemicals produced from captured carbon dioxide.