XAFS studies on copper(I) complexes containing scorpionate ligands

Cu-In Dual Sites with Sulfur Defects toward Superior Ethanol Electrosynthesis from CO2 Electrolysis

The electrosynthesis of multi-carbon chemicals from excess carbon dioxide (CO2) is an area of great interest for research and commercial applications. However, improving both the yield of CO2-to-ethanol conversion and the stability of the catalyst at the same time is proving to be a challenging issue. Here it is proposed to stabilize active Cu(I) and In dual sites with sulfur defects through an electro-driven intercalation strategy, which leads to the delocalization of electron density that enhances orbital hybridizations between the Cu-C and In-H bonds. Hence, the energy barrier for the rate-limiting *CHO formation step is reduced toward the key *OCHCHO* formation during ethanol production, which is also facilitated by the combined Cu site enabling C-C coupling and In site with a higher oxygen affinity based on both thermodynamic and kinetic calculations. Accordingly, such dual-site catalyst achieves a high partial current density toward ethanol of 409 ± 15 mA cm⁻2 for over 120 h. Furthermore, a scaled-up flow cell is assembled with an industrial-relevant current of 5.7 A for over 36 h, in which the carbon loss is less than 2.5% and single-pass carbon efficiency is ≈19%.

Coordination Polymer Electrocatalysts Enable Efficient CO-to-Acetate Conversion

Upgrading carbon dioxide/monoxide to multi-carbon C₂₊ products using renewable electricity offers one route to more sustainable fuel and chemical production. One of the most appealing products is acetate, the profitable electrosynthesis of which demands a catalyst with higher efficiency. Here, a coordination polymer (CP) catalyst is reported that consists of Cu(I) and benzimidazole units linked via Cu(I)-imidazole coordination bonds, which enables selective reduction of CO to acetate with a 61% Faradaic efficiency at -0.59 volts versus the reversible hydrogen electrode at a current density of 400 mA cm^-2 in flow cells. The catalyst is integrated in a cation exchange membrane-based membrane electrode assembly that enables stable acetate electrosynthesis for 190 h, while achieving direct collection of concentrated acetate (3.3 molar) from the cathodic liquid stream, an average single-pass utilization of 50% toward CO-to-acetate conversion, and an average acetate full-cell energy efficiency of 15% at a current density of 250 mA cm^-2 .