Unraveling the Cooperative Mechanisms in Ultralow Copper-Loaded WC@NGC for Enhanced CO₂ Electroreduction to Acetic Acid

Abstract

Electrochemical CO2 reduction reaction (eCO2RR) has been explored on tungsten carbide (WC) nanoparticles embedded on N-doped graphitic carbon (NGC), demonstrating excellent activity toward the formation of acetic acid at an extremely lower potential. The activity has been further enhanced by loading ultralow copper sites into the catalyst system, exhibiting 80.02% Faradaic efficiency (FE) toward acetic acid at an applied potential of −0.3 V (vs RHE). Potential-dependent in situ infrared (IR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, ex situ extended X-ray absorption fine structure (EXAFS) studies, and computational analysis confirm that synergy between uniformly dispersed Cu atoms and WC lattice plays a crucial role in the formation of acetic acid with high FE at a lower potential. It has been observed that the W atom of WC strongly chemisorbs CO2 with a significant change in the C–O bond length and the O–C–O bond angle, in contrast to weaker adsorption on Cu-based catalyst surfaces. The presence of a Cu site enhances the adsorption of CO2, thereby increasing the possibility of C–C coupling kinetically. Most importantly, hydrogen evolution predominates on the catalyst’s surface at higher applied potentials (−0.5 to −1.1 V vs RHE), elucidating the mechanism underlying enhanced charge transfer between copper and WC, a phenomenon ascertained through in situ IR spectroscopy and ex situ XPS analysis

Lattice Charge Tuning-Driven Multi-Carbon Products from Carbon Dioxide

“…This family of compounds, known for its diverse crystallographic properties, including both tetragonal (Tet) and orthorhombic (Orth) crystal systems, provides a nuanced platform for investigating the intricate relationship between lattice charge and catalytic behavior. Our comprehensive analysis not only aims to contribute to the understanding of lattice charge as a governing factor in catalysis but also underscores the importance of considering materials with similar compositions for meaningful comparisons. − This provides a promising avenue to investigate the role of lattice charge distribution in chemically equivalent systems but with different spatial arrangements and to understand its effect on the formation of eCO 2 RR products. We have previously employed secondary elements to tune the electronic properties of a catalyst. − Extending this knowledge, we selected secondary elements to have a negligible contribution to the hydrogen evolution reaction (HER).…”