Various advanced catalysts based on sulfur-doped Fe/N/C materials have recently been designed for the oxygen reduction reaction (ORR); however, the enhanced activity is still controversial and usually attributed to differences in the surface area, improved conductivity, or uncertain synergistic effects. Herein, a sulfur-doped Fe/N/C catalyst (denoted as Fe/SNC) was obtained by a template-sacrificing method. The incorporated sulfur gives a thiophene-like structure (C-S-C), reduces the electron localization around the Fe centers, improves the interaction with oxygenated species, and therefore facilitates the complete 4 e ORR in acidic solution. Owing to these synergistic effects, the Fe/SNC catalyst exhibits much better ORR activity than the sulfur-free variant (Fe/NC) in 0.5 m H SO .

The fabrication of Zn‐CO2 batteries is a promising technique for CO2 fixation and energy storage. Herein, nitrogen‐doped ordered mesoporous carbon (NOMC) is adopted as a bifunctional metal‐free electrocatalyst for CO2 reduction and oxygen evolution reaction in the near‐neutral electrolyte. The ordered mesoporous structures and abundant N‐dopings of NOMC facilitate the accessibility and utilization of the active sites, which endow NOMC with excellent electrocatalysis performance and outstanding stability. Especially, a nearly 100% CO Faradaic efficiency is achieved at an ultralow overpotential of 360 mV for CO2 reduction. When constructed as an aqueous rechargeable Zn‐CO2 battery using NOMC as the cathode, it yields a high peak power density of 0.71 mW cm−2, a good cyclability of 300 cycles, and excellent energy efficiency of 52.8% at 1.0 mA cm−2.

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Various advanced catalysts based on sulfur‐doped Fe/N/C materials have recently been designed for the oxygen reduction reaction (ORR); however, the enhanced activity is still controversial and usually attributed to differences in the surface area, improved conductivity, or uncertain synergistic effects. Herein, a sulfur‐doped Fe/N/C catalyst (denoted as Fe/SNC) was obtained by a template‐sacrificing method. The incorporated sulfur gives a thiophene‐like structure (C−S−C), reduces the electron localization around the Fe centers, improves the interaction with oxygenated species, and therefore facilitates the complete 4 e− ORR in acidic solution. Owing to these synergistic effects, the Fe/SNC catalyst exhibits much better ORR activity than the sulfur‐free variant (Fe/NC) in 0.5 m H2SO4.

Rechargeable aqueous Zn–CO2 batteries show great promise in meeting severe environmental problems and energy crises due to their combination of CO2 utilization and energy output, as well as advantages of high theoretical energy density, abundant raw materials, and high safety. Developing high‐efficiency and stable CO2 reduction reaction (CO2RR) electrocatalysts is of critical importance for the promotion of this technology. Atomically dispersed metal‐based catalysts (ADMCs), with extremely high atom‐utilization efficiency, tunable coordination environments, and superior intrinsic catalytic activity, are emerging as promising candidates for Zn–CO2 batteries. Herein, some recent developments in atomically dispersed metal‐based catalysts for Zn–CO2 batteries are summarized, including transition metal and non‐transition metal sites. Moreover, various synthetic strategies, characterization methods, and the relationship between active site structures and CO2RR activity/Zn–CO2 battery performance are introduced. Finally, some challenges and perspectives are also proposed for the future development of ADMCs in Zn–CO2 batteries.

Designing efficient and cost-effective bifunctional catalysts is desirable for carbon dioxide and oxygen reduction reactions (CO 2 RR and ORR) to address carbon neutralization and energy conversion. Herein, a bifunctional CO 2 RR and ORR catalyst for aqueous Zn-air battery (ZAB) self-driving CO 2 RR electrolysis is developed using atomically dispersed niobium anchored onto N-doped ordered mesoporous carbon (Nb-N-C). The Nb-N-C atomic catalyst demonstrates aqueous CO 2 RR activity with CO Faradaic efficiency up to 90%, ORR activity with a half-wave potential of 0.84 V vs. reversible hydrogen electrode, and ZAB activity with a peak power density of 115.6 mW cm −2 , owing to the high Nb atom-utilization efficiency and ordered mesoporous structure. Furthermore, two-unit ZABs in series, serving as the power source for the self-powered CO 2 electrolysis system, continuously convert CO 2 to CO with average productivity of 3.75 μmol h −1 mg cat −1 during the first 10 h. Moreover, theoretical calculations exhibit that atomic Nb anchored to N-doped carbon can form Nb-N coordination bonds, effectively reducing the energy barriers of potential-determining * COOH for CO 2 RR and * O formation for ORR.

Emerging Fe bonded with heteroatom P in carbon matrix (FePC) holds great promise for electrochemical catalysis, but the design of highly active and cost‐efficient FePC structure for the electrocatalytic CO2 reduction reaction (CO2RR) and aqueous ZnCO2 batteries (ZCBs) is still challenging. Herein, polyhedron‐shaped bifunctional electrocatalysts, FeP nanocrystals anchored in N‐doped carbon polyhedrons (Fe‐P@NCPs), toward a reversible aqueous ZnCO2 battery, are reported. The Fe‐P@NCPs are synthesized through a facile strategy by using self‐templated zeolitic imidazolate frameworks (ZIFs), followed by an in situ high‐temperature calcination. The resultant catalysts exhibit aqueous CO2RR activity with a CO Faradaic efficiency up to 95% at −0.55 V versus reversible hydrogen electrode (RHE), comparable to the previously best‐reported values of FeNC structure. The as‐constructed ZCBs with designed Fe‐P@NCPs cathode, show the peak power density of 0.85 mW cm−2 and energy density of 231.8 Wh kg−1 with a cycling durability over 500 cycles, and outstanding stability in terms of discharge voltage for 7 days. The high selectivity and efficiency of the battery are attributed to the presence of highly catalytic FeP nanocrystals in N‐doped carbon matrix, which can effectively increase the number of catalytically active sites and interfacial charge–transfer conductivity, thereby improving the CO2RR activity.

Exploring reversible Zn–CO2 batteries holds great promising potential for future CO2 fixation and energy supply. Herein, the bifunctional PdBi alloy anchoring on carbon substrate (BiPdC) is proposed for simultaneously catalyzing carbon dioxide reduction reaction (CO2RR) and formic acid oxidation (FAO). The synergistic effect between Pd and Bi overcomes the sluggish kinetics of CO2RR and FAO, causing the HCOOH Faraday efficiency (FEHCOOH) of 63.4% and 6.2 mA cm–2 current density for FAO. Benefiting from the CO2–HCOOH interconversion, the homemade reversible Zn–CO2 battery exhibits the optimal 52.6% FEHCOOH and 1.1 V voltage gap within 45 h of cycling.