Operando reconstruction towards stable CuI nanodots with favorable facets for selective CO2 electroreduction to C2H4

This study is led by Prof. Bo You, Prof. Bao Yu Xia and Prof. Xuan Yang (School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology). They experimentally fabricate CuI nanodots with favorable (220) facets and a stable Cu⁺ state, accomplished by operando reconstruction of Cu(OH)₂ under CO₂- and I^--containing electrolytes for enhanced CO₂-to-C₂H₄ conversion.

Cu-based electrocatalysts with favorable facets and Cu⁺ can boost CO₂ reduction to valuable multicarbon products. Unfortunately, the Cu⁺ inevitably undergoes electroreduction to Cu⁰ during CO₂R process even if a variety of innovative stabilization approaches, such as secondary metals/heteroatoms doping, plasma treating, and matrix incorporating are employed. Concomitantly, the morphology reconstruction of catalysts usually leads to dynamical actives sites and/or deteriorated C₂₊ selectivity as well as complicates the studies of structure-activity correlation. It’s still challenging to explore advanced Cu-based electrocatalysts with both favorable facets and stable Cu⁺ state for selective CO₂-to-C₂H₄ conversion.

Different from previous reports that focus on metallic/oxidized Cu, researchers herein fabricate cuprous iodide (CuI) nanodots (diameter of 5.3 nm) with favorable (220) facets and stable Cu⁺ state for improved CO₂-to-C₂₊ (C₂H₄) conversion through operando reconstruction of Cu(OH)₂ precursors under CO₂- and I^-- contained electrolyte. The high thermodynamic potential of Cu²⁺/CuI relative to Cu²⁺/Cu⁺(Cu⁰) benefits formation of stable CuI rather than metallic Cu during CO₂R process, as revealed by X-ray absorption spectroscopy and in-situ Raman spectroscopy investigation. CO₂-related intermediates along reductive pathways serve as capping agents to shape the formation of CuI(220). The adequate contact of nanodots with I^- due to the small size guarantees rapid formation of CuI rather than electroreduction to Cu⁰. As a result, they achieve a high C₂H₄ Faradaic efficiency (FE) of 72.4% at 800 mA cm^-2 and long-term stability for the resulting CuI nanodots. In-situ attenuated total reflection surface-enhanced Fourier-transform infrared spectroscopy (ATR-SEIRS) and density functional theory results indicate the high-index CuI(220) facets and stable Cu⁺ collectively facilitate CO₂/*CO adsorption and subsequent *CO dimerization for improved C₂H₄ generation.

See the article:

Operando reconstruction towards stable CuI nanodots with favorable facets for selective CO₂ electroreduction to C₂H₄

https://doi.org/10.1007/s11426-023-1591-6

---

---