Yao Yang1,Sheena Louisia1,Sunmoon Yu1,Hector Abruna2,Peidong Yang1
University of California, Berkeley1,Cornell University2
Yao Yang1,Sheena Louisia1,Sunmoon Yu1,Hector Abruna2,Peidong Yang1
University of California, Berkeley1,Cornell University2
In an era of shifting the energy paradigm from fossil fuels to renewable energy, CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) emerges as a promising approach to covert greenhouse gas into valuable chemical fuels and close the carbon cycle for a sustainable energy supply. Since Cu remains the sole element for CO<sub>2</sub>RR to multicarbon products (C<sub>2+</sub>), significant efforts have been devoted to developing Cu electrocatalysts with higher selectivity and activity. However, the complex nature of active sites and the intrinsic structures under reaction conditions have remained largely elusive due to the lack of <i>operando</i>/<i>in situ</i> methods.<sup>1-3</sup><br/>In our previous studies, we reported that small Cu nanoparticles (sub-10 nm NPs) showed superior C<sub>2+</sub> superior C<sub>2+</sub> selectivity, relative to the larger sized Cu NPs, especially at low overpotentials.<sup>4,5</sup> In this work, we present a comprehensive <i>operando</i> correlative study of dynamic evolution of a family of monodisperse Cu NP ensemble electrocatalysts under CO<sub>2</sub>RR.<sup>1</sup> <i>Operando</i> electrochemical liquid-cell scanning transmission electron microscopy (EC-STEM) and 4D-STEM resolves microscopic dynamic morphological and structural evolution at the nm scale. Correlated <i>operando</i> high-energy-resolution fluorescence detected (HERFD) X-ray absorption spectroscopy (XAS) reveals dynamic macroscopic changes in valence states and coordination environment. Statistical analysis of interparticle dynamics was probed by <i>operando </i>resonant soft X-ray-based resonant soft X-ray scattering (RSoXS).<sup>2</sup> The <i>operando</i> correlative strategies, described herein, elucidates the longstanding enigmatic nature of Cu active sites for selective CO<sub>2</sub> electroreduction. The strategy described herein can serve as a general platform to resolve the electrocatalytic interface of nanoparticle catalysts under real-time operating conditions across multiple time and length scales, thus serving the fundamental understanding necessary to development of many other electrochemical reactions for renewable energy technologies.<br/><br/><b>References: </b><br/>Yang, Y., Louisia, S., Yu, S., Yang, P. et al. <i>Operando</i> Studies Reveal Active Cu Nanograins for CO<sub>2</sub> Electroreduction. <b><i>Nature</i></b> 2022, Accepted.<br/>Yang, Y., Yang, P., et al. <i>Operando </i>Resonant Soft X-ray Scattering Studies of Chemical Environment and Interparticle Dynamics of Cu Nanocatalysts for CO2 Electroreduction. <b><i>J. Am. Chem. Soc</i></b><i>. </i>2022, <i>144</i>, 8927−8931.<br/>Yang, Y., Abruna, H. D. et al. <i>Operando </i>Methods in Electrocatalysis. <b><i>ACS Catal</i></b>. 2021, 11, 1136-1178.<br/>Kim, D., Yang, P. et al. Copper Nanoparticle Ensembles for Selective Electroreduction of CO2 to C2−C3 Products. <b><i>Proc. Natl. Acad. Sci. U.S.A</i></b><i>.</i> 2017, 114, 10560−10565.<br/>Li, Y., Yang, P. et al. Electrochemically Scrambled Nanocrystals are Catalytically Active for CO2-to-Multicarbons. <b><i>Proc. Natl. Acad. Sci. U.S.A</i></b>. 2020, 117, 9194−9201.