关键词: 低浓度CO₂电还原, 离子液体, Cu_2xSe, 纳米限域, 甲醇

Abstract: The electrocatalytic reduction of dilute carbon dioxide (CO₂) to methanol faces dual challenges of sluggish reaction kinetics and the competing hydrogen evolution reaction (HER). This study presents a nanoconfined ionic liquid catalyst strategy, in which Cu_2‒xSe nanocrystals are anchored as catalytic engines within mesoporous nitrogen-doped carbon nanofibers (CSNC), followed by impregnation with the ionic liquid [Emim][BF₄] to modulate the reaction microenvironment. The multilevel pore structure of the catalyst enables local enrichment of CO₂ through a nanoconfinement effect, while the homogeneous distribution of the ionic liquid combined with a hydrophobic interface collectively suppresses HER, thereby enhancing methanol selectivity. In an H-type cell with 0.5 mol/L KHCO₃, CSNC/[Emim][BF₄] achieves a peak methanol Faradaic efficiency (FE) of 79.4% at 0.52 V vs. RHE, sustaining > 70% FE over 48 h. In a flow cell with 1 mol/L KOH, FE reaches 78.8% under pure CO₂ and 72.3% under 10% CO₂ (simulating flue gas), 1.67 times higher than CSNC alone, with stable performance over 24 h. In situ spectroscopy and feedstock-switching experiments reveal N-coordination stabilizes *COOH intermediates, favoring methanol via the formate pathway. This strategy advances selective, stable CO₂-to-methanol conversion from dilute streams, promoting sustainable carbon utilization and industrial flue gas valorization.

Key words: Low-concentration CO₂ electroreduction, Ionic liquids, Cu_2-xSe, Nano-confinement, Methanol