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 CO 2 - and I - -containing electrolytes for enhanced CO 2 -to-C 2 H 4 conversion.
Cu-based electrocatalysts with favorable facets and Cu + can boost CO 2 reduction to valuable multicarbon products. Unfortunately, the Cu + inevitably undergoes electroreduction to Cu 0 during CO 2 R 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 C 2+ 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 CO 2 -to-C 2 H 4 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 CO 2 -to-C 2+ (C 2 H 4 ) conversion through operando reconstruction of Cu(OH) 2 precursors under CO 2 - and I - - contained electrolyte. The high thermodynamic potential of Cu 2+ /CuI relative to Cu 2+ /Cu + (Cu 0 ) benefits formation of stable CuI rather than metallic Cu during CO 2 R process, as revealed by X-ray absorption spectroscopy and in-situ Raman spectroscopy investigation. CO 2 -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 Cu 0 . As a result, they achieve a high C 2 H 4 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 CO 2 /*CO adsorption and subsequent *CO dimerization for improved C 2 H 4 generation.
See the article:
Operando reconstruction towards stable CuI nanodots with favorable facets for selective CO 2 electroreduction to C 2 H 4
https://doi.org/10.1007/s11426-023-1591-6
Science China Chemistry