Hybrid Electrocatalyst-Microenvironment Interfaces for Sustainable Resourcification and Energy Conversion

Abstract

<p>Overcoming the activity-selectivity-durability trilemma of electrocatalysis is key to realizing a sustainable society in the future powered by renewable energy sources. However, lowering the overpotential (activation barrier), increasing the activity (turnover frequency), improving the selectivity (product speciation), and enhancing the stability (catalyst robustness) have been difficult to achieve simultaneously despite decades of collective efforts in the field of electrocatalysis. To address these challenges, I adopt an interdisciplinary approach to design bio-inspired electrodes. These hybrid electrochemical interfaces feature non-precious multimetallic active sites to refine binding interactions with substrates and key intermediates. Cocatalysts further regulate proton-coupled electron transfer (PCET) steps that are critical and commonly found in these redox half-reactions, thereby modulating the rate-determining step (RDS) and selectivity-governing step (SGS).</p><p>In this talk, I will first introduce our work toward achieving exclusive reduction of nitrate into ammonia by bimetallic layered double hydroxides (LDH) as synergistic electrocatalysts.[1] In this work, the cooperative roles of Cu and Co in the LDH framework are explored to understand how they facilitate nitrate adsorption, lower the activation barrier of the rate determining step, bind with electrolytes to tune the selectivity governing step, and ultimately generate ammonia with close to 100% Faradaic efficiency. Next, I will discuss our strategy to facilitate O₂ reduction through the development of nature-inspired electrocatalytic interfaces.[2][3] Specifically, I address the activity-selectivity-durability trilemma of O₂ reduction through (i) hybrid bilayer membrane technology that can tailor the exquisite proton-coupled electron transfer processes within the electrocatalyst-microenvironment confinement and (ii) mechanical interlocking metal complexes that can capture the co-conformation dynamics of enzyme backbones to switch the O₂ binding mode from side-on to end-on and elongate the O–O bond for efficient cleavage. Lastly, I will present our progress on devising a programmable 3D laser printing technology to fabricate integrated electrodes with binderless earth-abundant electrocatalysts to realize scalable production of key industrial synthons.[4] Going forward, I aim to take advantage of our hybrid electrochemical interfaces to unravelling key insights on how catalyst microenvironment impacts the performance of bioinorganic electrocatalysts for advanced redox conversion technology.<br></p>