Lithiation‐Enabled High‐Density Nitrogen Vacancies Electrocatalyze CO₂ to C₂ Products

Abstract

Electrochemical CO2 reduction to produce valuable C2 products is attractive but still suffers with relatively poor selectivity and stability at high current densities, mainly due to the low efficiency in the coupling of two *CO intermediates. Herein, it is demonstrated that high‐density nitrogen vacancies formed on cubic copper nitrite (Cu3Nx) feature as efficient electrocatalytic centers for CO–CO coupling to form the key OCCO* intermediate toward C2 products. Cu3Nx with different nitrogen densities are fabricated by an electrochemical lithium tuning strategy, and density functional theory calculations indicate that the adsorption energies of CO* and the energy barriers of forming key C2 intermediates are strongly correlated with nitrogen vacancy density. The Cu3Nx catalyst with abundant nitrogen vacancies presents one of the highest Faradaic efficiencies toward C2 products of 81.7 ± 2.3% at −1.15 V versus reversible hydrogen electrode (without ohmic correction), corresponding to the partial current density for C2 production as −307 ± 9 mA cm−2. An outstanding electrochemical stability is also demonstrated at high current densities, substantially exceeding CuOx catalysts with oxygen vacancies. The work suggests an attractive approach to create stable anion vacancies as catalytic centers toward multicarbon products in electrochemical CO2 reduction.

Tuning the Metal Electronic Structure of Anchored Cobalt Phthalocyanine via Dual‐Regulator for Efficient CO2 Electroreduction and Zn–CO2 Batteries

“…Electrochemical reduction of carbon dioxide (CO 2 RR) toward high-valued product and closing the anthropogenic carbon cycle, powered by renewable electricity, has emerged as a competitive solution to achieve CO 2 resource re-utilization. [1][2][3][4] CO 2to-CO conversion has sparked tremendous attention, since CO…”

Highly‐Exposed Single‐Interlayered Cu Edges Enable High‐Rate CO2‐to‐CH4 Electrosynthesis

“…The peak j CH 4 of 717 ± 33 mA cm −2 on the CuGaO 2 nanosheet catalyst represents the highest reported electrochemical CO 2 -to-CH 4 value to date (Figure 4e; Table S6, Supporting Information). [9][10][11][12][13]15,[29][30][31][32][33][34][35][36][37][38] S6, Supporting Information). f) Applied potentials (grey curve, left y-axis) and FE CH 4 (blue squares, right y-axis) versus time using the CuGaO 2 nanosheet catalyst at a constant total current density of -1 A cm −2 .…”

RuO2 electronic structure and lattice strain dual engineering for enhanced acidic oxygen evolution reaction performance

“…In addition to doping, electrochemical ion insertion involving coupled ion–electron transfer is also an effective method to introduce alien elements into a host material for electronic or crystal structure modulation, and has been considered as a synthetic strategy to improve the catalytic performance of layer-structured materials 27 – 29 , such as LiCoO 2 for OER 30 and MoS 2 for HER 28 , where the Li concentration is an adjustable variable over a wide range 31 , 32 . Recently, Zheng’s group utilized a lithiation strategy to improve the CO 2 reduction performance of catalysts, including Cu 3 N x 33 and Sn 34 . Various studies have shown that RuO 2 can be inserted with Li ions for battery applications, and a solid solution phase forms before a Li:Ru = 1:1 ratio is reached 35 – 38 .…”