Fig. 2. Experimental investigations of EAH on NHC–metal complexes.

a Polarization curves of NHC–metal complexes in a 1 M KOH aqueous solution under pure acetylene flow. b Ethylene FEs of NHC–metal complexes in a 1 M KOH aqueous solution at different potentials under pure acetylene flow. c Ethylene FEs for NHC–metal complexes, NHC, and gas diffusion electrodes at −0.9 V vs. reversible hydrogen electrode (RHE) in a 1 M KOH aqueous solution. d Partial current density to ethylene for NHC–metal complexes in a 1 M KOH aqueous solution at different potentials under pure acetylene flow. e In situ electrochemical Raman spectra of NHC–Cu in a 1 M KOH aqueous solution. For clarity, the spectral regions of 1500–1700 and 1850–2150 cm⁻¹ were expanded.