Developing efficient catalysts for steering the electrochemical CO2 reduction reaction (CO2RR) toward high-value chemicals beyond CO and formic acid is highly desirable. Herein, we have developed copper-based catalysts confined within a rationally designed covalent triazine framework (CTF-B), featuring a CuN2Cl2 structure, for selective CO2RR to hydrocarbons with a maximum Faradaic efficiency (FE) of 81.3% and an FE of C2H4 up to 30.6%. Operando X-ray adsorption fine structure analyses reveal the potential-driven dynamic formation of Cu atomic clusters, together with the time-dependent and Cu-content-dependent CO2RR performance associated with the catalyst activation, definitively uncovering that the aggregated Cu clusters confined within CTF-B are the active sites. A further probing experiment of CO electroreduction not only verifies that CO is one of the key intermediates for the CO2RR but also demonstrates the improved selectivity to C2 chemicals, with a maximum FE of 68.4% (C2H4, 35.0%; acetate, 33.4%), possibly originating from the accelerative C–C coupling reaction due to the increased CO coverage and enhanced local pH in CO-saturated electrolyte. Interestingly, acetate is identified as the only liquid product, mostly likely benefiting from the dominant low-coordination active sites of confined Cu aggregation and favorable chemical confinement environment of CTF-B. The strategy of constructing efficient metalloelectrocatalysts by means of confinement in a covalent organic framework along with operando identification of active sites sheds light on the rational catalyst design and structure–property relationship.

Co/Zn atomic dual-sites anchored on N doped carbon nanofibers for efficient and durable H2–O2 fuel cells (∼0.65 V @ 400 mA cm−2, 150 hours).

The conversion of CO 2 into valuable chemicals has captured extensive attention for its significance in energy storage and greenhouse gas alleviation, but the development of cost-effective electrocatalysts with high activity and selectivity remains the bottleneck. Herein, we designed a Fe−N−C nanofiber catalyst featuring a core−shell structure consisting of iron nitride nanoparticles encapsulated within Fe and N codoped carbon layers that can efficiently catalyze CO 2 to CO with nearly 100% selectivity, high faradic efficiency (∼95%), and remarkable durability at −0.53 V versus reversible hydrogen electrode. Theoretical calculations reveal that the introduction of an iron nitride core can facilitate the CO intermediate desorption from the Fe and N codoped shell, thus enhancing the catalytic performance of CO 2 reduction. This work presents an ideal approach to rationally design and develop transitionmetal and N codoped carbon materials for efficient CO 2 reduction.C O 2 electroreduction reaction (CO 2 RR) is a promising strategy to convert CO 2 into multifarious valuable chemicals and synthetic fuels. The ultimate feasibility of this conversion, however, is currently impeded by the high overpotential, poor selectivity, and structural instability. Research efforts have been devoted to developing highperformance CO 2 RR electrocatalysts, primarily focused on the metallic electrodes, such as metal, 1 metal oxides, 2 or metal alloys. 3 Through control of the morphology of the electrode, 4 particle size, 5 geometry of the metallic surface, 6,7 and working electrolyte, 8,9 CO 2 can be converted into different products, such as CO, CH 4 , HCOOH, and other hydrocarbons. 10,11 These products are always yielded at a high overpotential, leading to unsatisfactory energy efficiency. Simultaneously, the hydrogen evolution reaction (HER) happens in the company of the CO 2 RR, thus resulting in the poor selectivity for the target product. Recently, the noble metals, such as Ag 12 or Au, 13,14 were found to efficiently catalyze the electroreduction of CO 2 to CO with high selectivity. Nevertheless, their prohibitive cost and high overpotential make this approach economically challenging.