Herein, we construct a novel electrocatalyst with Fe–Co dual sites embedded in N-doped carbon nanotubes ((Fe,Co)/CNT), which exhibits inimitable advantages towards the oxygen reduction reaction.

Nonaqueous rechargeable lithium–oxygen batteries (LOBs) are one of the most promising candidates for future electric vehicles and wearable/flexible electronics. However, their development is severely hindered by the sluggish kinetics of the ORR and OER during the discharge and charge processes. Here, we employ MOF-assisted spatial confinement and ionic substitution strategies to synthesize Ru single atoms riveted with nitrogen-doped porous carbon (Ru SAs-NC) as the electrocatalytic material. By using the optimized Ru0.3 SAs-NC as electrocatalyst in the oxygen-breathing electrodes, the developed LOB can deliver the lowest overpotential of only 0.55 V at 0.02 mA cm–2. Moreover, in-situ DEMS results quantify that the e–/O2 ratio of LOBs in a full cycle is only 2.14, indicating a superior electrocatalytic performance in LOB applications. Theoretical calculations reveal that the Ru–N4 serves as the driving force center, and the amount of this configuration can significantly affect the internal affinity of intermediate species. The rate-limiting step of the ORR on the catalyst surface is the occurrence of 2e– reactions to generate Li2O2, while that of the OER pathway is the oxidation of Li2O2. This work broadens the field of vision for the design of single-site high-efficiency catalysts with maximum atomic utilization efficiency for LOBs.

Electrochemical CO2 reduction can produce valuable products with high energy densities but the process is plagued by poor selectivities and low yields. Propanol represents a challenging product to obtain due to the complicated C3 forming mechanism that requires both stabilization of *C2 intermediates and subsequent C1–C2 coupling. Herein, density function theory calculations revealed that double sulfur vacancies formed on hexagonal copper sulfide can feature as efficient electrocatalytic centers for stabilizing both CO* and OCCO* dimer, and further CO–OCCO coupling to form C3 species, which cannot be realized on CuS with single or no sulfur vacancies. The double sulfur vacancies were then experimentally synthesized by an electrochemical lithium tuning strategy, during which the density of sulfur vacancies was well-tuned by the charge/discharge cycle number. The double sulfur vacancy-rich CuS catalyst exhibited a Faradaic efficiency toward n-propanol of 15.4 ± 1% at −1.05 V versus reversible hydrogen electrode in H-cells, and a high partial current density of 9.9 mA cm−2 at −0.85 V in flow-cells, comparable to the best reported electrochemical CO2 reduction toward n-propanol. Our work suggests an attractive approach to create anion vacancy pairs as catalytic centers for multi-carbon-products.

In view of the sluggish kinetics suppressing the oxygen evolution reaction (OER), developing efficient and robust OER catalysts is urgent and essential for developing efficient energy conversion technologies. Herein, hybrid amorphous/crystalline FeCoNi layered double hydroxide (LDH)‐supported single Ru atoms (Ru SAs/AC‐FeCoNi) are developed for enabling a highly efficient electrocatalytic OER. The amorphous outer layer in Ru SAs/AC‐FeCoNi is composed of abundant defect sites and unsaturated coordination sites, which can serve as anchoring sites to stabilize single Ru atoms. The crystalline inner has a highly symmetric rigid structure, thereby strengthening the stability of support for a long‐lasting OER. The synergistic effects endow this hybrid catalyst with extremely low overpotential (205 mV at 10 mA cm−2). Density functional theory calculation indicates that single Ru atoms stabilized by hybrid amorphous/crystalline FeCoNi LDH facilitate the formation of Ru–O* (rate‐determining step), thus accelerating the OER process.

The design of high-efficiency non-noble bifunctional electrocatalysts for oxygen evolution reaction and hydrogen evolution reaction is paramount for water splitting technologies and associated renewable energy systems. Spinel-structured oxides with rich redox properties can serve as alternative low-cost electrocatalysts. However, the spinel-structured oxides is a typical electrocatalyst for OER but with poor HER performance. In this work, zirconium regulation in threedimensional (3D) CoFe 2 O 4 (CoFeZr oxides) nanosheets on nickel foam (NF) as a novel strategy inducing bifunctionality toward OER and HER for overall water splitting is reported. The results demonstrate that the incorporation of Zr into CoFe 2 O 4 can tune the nanosheet morphology and electronic structure around Co and Fe sites for optimizing adsorption energies, thus effectively enhancing the intrinsic activity of active sites. The as-synthesized optimal electrocatalyst of 3D CoFeZr oxides nanosheets exhibited high OER activity with small overpotential, low Tafel slope and good stability. Moreover, the CoFeZr oxide nanosheets showed unprecedented HER activity with a small overpotential of 104 mV at 10 mA cm −2 in alkaline media, which is better than ever reported This article is protected by copyright. All rights reserved.3 spinel-structured oxides. When employing the CoFeZr oxides nanosheets as both anode and cathode catalysts for overall water splitting, a current density of 10 mA cm 2 was achieved at the cell voltage of 1.63 V in 1.0 M KOH. The results demonstrate that such favorable OER and HER activity can be attributed to fast electron transportation, improved electrical conductivity and optimal electronic structure.

The exploration of cost‐effective yet high‐efficiency inexpensive electrocatalysts for the hydrogen evolution reaction (HER) is of critical significance for future renewable energy conversion technologies. A feasible electrospinning strategy to construct a novel 1D hierarchical nanoarchitecture comprising Ni3Fe nanoalloy‐encapsulated carbon nanotubes grown onto N‐doped carbon nanofibers (abbreviated as Ni3Fe@N‐C NT/NFs) is demonstrated here. Benefiting from the abundant firmly immobilized Ni3Fe nanoparticles for catalytic sites and hierarchical fibrous nanostructures for effective electron transport and mass diffusion, the resultant Ni3Fe@N‐C NT/NFs display an extraordinary HER activity with a low overpotential of 72 mV to reach a current density of 10 mA cm−2 in KOH medium and a remarkable stability for 40 000 s. Theoretical studies corroborate that the resultant Ni3Fe@N‐C NT/NFs exhibit a favorable Gibbs free energy of hydrogen adsorption (ΔGH* = −0.14 eV), further manifesting their superior HER activity. The present work will advance the development of highly efficient nonprecious electrocatalysts for energy conversion.

Dual-metal-site catalysts could exhibit superior activity for CO2 electroreduction to CO due to the breaking of scaling relationship.

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.