Operando Probing of Electrochemical Reactions At Triple-phase-boundaries

Electrochemical conversion is central to the net-zero transition, enabling hydrogen production from renewable energy and water, and the transformation of waste CO2 into valuable fuels and chemicals. However, these multi-step reactions take place at triple-phase boundaries which are challenging to experimentally access, limiting our understanding and thus ability to rationally design improved electrocatalysts. OPERATE will deliver new capabilities to observe the chemical state, intermediate species and underlying reaction mechanisms at these triple-phase boundaries under realistic reaction conditions, to inform the development of earth-abundant electrocatalysts for sustainable chemical production. Operando X-ray spectroscopy approaches will be developed to observe solid-liquid and solid-gas boundaries under high current-density and mass-transport regimes, using nano porous membranes to separate liquid and gas phases. Combinatorial screening of multicomponent nanoparticles, combined with high throughput electrochemical testing will enable mapping of the electrochemical and compositional parameter space such that operando characterisation can obtain the most detailed mechanistic insights. Control of composition, phase and size of multicomponent nanoparticles will tune the extent to which lattice oxygen participates in the oxygen evolution reaction, and the presence of synergistic sites to guide CO2 reduction towards desired products. In contrast to previous approaches, electrolyser-relevant current densities and mass-transport regimes will be used throughout the catalyst screening process to ensure translation to scaled-up devices, which will be confirmed using advanced operando studies with newly developed zero-gap electrolyser formats. OPERATE will thereby accelerate the development of electrocatalysts for gas-evolving and gas-consuming reactions, by revealing and understanding the underlying reaction mechanisms to inform rational catalyst design.