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Normally, the CO2 reduction reaction (CO2RR) on Fe‐based materials is unfavorable due to the poisoning of reaction sites by CO products. By modulating the electronic structures of Fe sites via carbonization, the CO binding strength can be optimized to facilitate the CO2RR. In the present study, a dual N‐elimination strategy is adopted to synthesize and stabilize a rarely reported iron carbide phase Fe2C nanoclusters with a mean diameter of 1.07 nm trapped in topological carbon defects. Notably, the ultrafine Fe2C clusters present an excellent performance on electrocatalytic CO2RR, which can drive a current density of 8.53 mA cm−2 with Faradaic efficiency of 97.1% for CO production at −0.7 V versus reversible hydrogen electrode. Density functional theory calculations reveal that the nanometric Fe2C cluster possesses much weaker binding with CO than the Fe crystalline surfaces and other iron carbides, thus promoting the CO desorption and overall CO2RR process. [ABSTRACT FROM AUTHOR]

The electrocatalytic carbon dioxide (CO2) reduction is a promising approach for converting this greenhouse gas into value‐added chemicals, while the capability of producing products with longer carbon chains (Cn>3) is limited. Herein, we demonstrate the Br‐assisted electrocatalytic oxidation of ethylene (C2H4), a major CO2 electroreduction product, into 2‐bromoethanol by electro‐generated bromine on metal phthalocyanine catalysts. Due to the preferential formation of Br2 over *O or Cl2 to activate the C=C bond, a high partial current density of producing 2‐bromoethanol (46.6 mA⋅cm−2) was obtained with 87.2 % Faradaic efficiency. Further coupling with the electrocatalytic nitrite reduction to ammonia at the cathode allowed the production of triethanolamine with six carbon atoms. Moreover, by coupling a CO2 electrolysis cell for in situ C2H4 generation and a C2H4 oxidation/nitrite reduction cell, the capability of upgrading of CO2 and nitrite into triethanolamine was demonstrated. [ABSTRACT FROM AUTHOR]

Bulk ceria can stabilize metal single atoms in oxidizing conditions. However, the obtained catalysts undergo sintering at high temperatures, due to the poor stability of the support. In this work, we prepared ordered mesoporous ceria (mp-CeO 2) to trap Ni single atoms in dry reforming of CH 4 (DRM). We found that the Ni 1 @mp-CeO 2 catalyst presented many oxygen vacancies (O V) and basic sites, helping to activate CO 2 and generate reactive oxygen to remove carbon deposits, as compared to a Ni 1 /CeO 2 sample prepared by impregnation. Moreover, the confinement of mesoporous CeO 2 prevents the sintering of Ni clusters derived from Ni single atoms and enhances the stability of the catalyst. The Ni 1 @mp-CeO 2 catalyst has a higher CH 4 conversion, and less deactivation rate, as compared to the Ni 1 /CeO 2. This work demonstrates Ni single atoms undergo growth to nanoclusters in DRM and the use of Ni single atoms as catalyst precursor can suppress the carbon deposition. [Display omitted] • Evolution of Ni single atoms trapped by ordered mesoporous ceria (mp-CeO 2) for catalysis. • Ni 1 @mp-CeO 2 catalyst presenting a great number of oxygen vacancies and basic sites, helping to activate CO 2 molecules and remove carbon deposits. • The confinement effect of mp-CeO 2 prevents the sintering of Ni clusters derived from Ni single atoms, and enhance the stability of the catalyst. [ABSTRACT FROM AUTHOR]

The rational integration of multiple functional units into heterogeneous materials to improve catalytic performance is highly desirable for CO 2 value-added processes. Herein, a catalyst composed of porous carbon matrix with atomically dispersed Lewis acid sites (i.e., AlO 5 motifs) and imidazolium-based poly(ionic liquid)s (denoted as PILs@Al-O-C) was fabricated. Compared with pure Al-O-C or PILs, the optimized PILs@Al-O-C exhibits superior catalytic performance (>90% yield) towards cycloaddition reaction of CO 2 and epoxides in the absence of solvent and co-catalyst. The enhanced activity of PILs@Al-O-C is attributed to the synergistic effect among the uniform N sites (Lewis base sites) and abundant bromide anions (nucleophilic agents) in the PILs network, as well as the atomically dispersed Al sites (Lewis acid sites) in the Al-O-C matrix. This work provides an advanced PILs@Al-O-C catalyst for constructing a neat catalytic system towards CO 2 fixation. In this work, a carbon-based catalyst featuring atomically dispersed AlO 5 motifs and imidazolium-based PILs network (denoted as PILs@Al-O-C) was rationally fabricated. The optimized PILs@Al-O-C achieves superior catalytic performance towards CO 2 cycloaddition reaction in the absence of solvent and co-catalyst by the integration of the uniform Lewis base sites (i.e., N sites) and abundant nucleophilic anions (i.e., Brˉ) from PILs, as well as the atomically dispersed Lewis acid sites (i.e., AlO 5 motifs) in the carbon matrix. [Display omitted] • This work represents the first attempt on combination of single-atom catalysis with PILs towards CO 2 cycloaddition with epoxides in the absence of solvent and co-catalyst. • The uniform Lewis base sites (i.e., N sites) and abundant nucleophilic anions (i.e., Brˉ) from PILs, as well as the atomically dispersed Lewis acid sites (i.e., AlO 5 motifs) in the carbon matrix synergistically promote the activation of epoxides and subsequent CO 2 cycloaddition reaction. [ABSTRACT FROM AUTHOR]