Operando studies reveal active Cu nanograins for CO 2 electroreduction.
Yao YangSheena LouisiaSunmoon YuJianbo JinInwhan RohChubai ChenMaria V Fonseca GuzmanJulian FeijóoPeng-Cheng ChenHongsen WangChristopher J PollockXin HuangYu-Tsun ShaoCheng WangDavid A MullerHector D AbrunaPeidong YangPublished in: Nature (2023)
Carbon dioxide electroreduction facilitates the sustainable synthesis of fuels and chemicals 1 . Although Cu enables CO 2 -to-multicarbon product (C 2+ ) conversion, the nature of the active sites under operating conditions remains elusive 2 . Importantly, identifying active sites of high-performance Cu nanocatalysts necessitates nanoscale, time-resolved operando techniques 3-5 . Here, we present a comprehensive investigation of the structural dynamics during the life cycle of Cu nanocatalysts. A 7 nm Cu nanoparticle ensemble evolves into metallic Cu nanograins during electrolysis before complete oxidation to single-crystal Cu 2 O nanocubes following post-electrolysis air exposure. Operando analytical and four-dimensional electrochemical liquid-cell scanning transmission electron microscopy shows the presence of metallic Cu nanograins under CO 2 reduction conditions. Correlated high-energy-resolution time-resolved X-ray spectroscopy suggests that metallic Cu, rich in nanograin boundaries, supports undercoordinated active sites for C-C coupling. Quantitative structure-activity correlation shows that a higher fraction of metallic Cu nanograins leads to higher C 2+ selectivity. A 7 nm Cu nanoparticle ensemble, with a unity fraction of active Cu nanograins, exhibits sixfold higher C 2+ selectivity than the 18 nm counterpart with one-third of active Cu nanograins. The correlation of multimodal operando techniques serves as a powerful platform to advance our fundamental understanding of the complex structural evolution of nanocatalysts under electrochemical conditions.
Keyphrases
- aqueous solution
- metal organic framework
- stem cells
- electron microscopy
- photodynamic therapy
- carbon dioxide
- machine learning
- single cell
- nitric oxide
- magnetic resonance
- gene expression
- chronic pain
- computed tomography
- ionic liquid
- mesenchymal stem cells
- pain management
- mass spectrometry
- contrast enhanced
- light emitting