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Achieving efficient efficiency and selectivity for the electroreduction of CO2 to value‐added feedstocks has been challenging, due to the thermodynamic stability of CO2 molecules and the competing hydrogen evolution reaction. Herein, a dual‐single‐atom catalyst consisting of atomically dispersed CuN4 and NiN4 bimetal sites is synthesized with electrospun carbon nanofibers (CuNi‐DSA/CNFs). Theoretical and experimental studies reveal the strong electron interactions induced by the electronegativity offset between the Cu and Ni atoms. The delicately averaged and compensated electronic structures result in an offset effect that optimizes the adsorption strength of the *COOH intermediate and boosts the CO2 reduction reaction (CO2RR) kinetics, notably promoting the intrinsic activity and selectivity of the catalyst. The CuNi‐DSA/CNFs catalyst exhibits an outstanding FECO of 99.6% across a broad potential window of −0.78– −1.18 V (vs the reversible hydrogen electrode), a high turnover frequency of 2870 h–1, and excellent durability (25 h). Furthermore, an aqueous Zn‐CO2 battery for CO2 power conversion is constructed. This atomic‐level electronegativity offset of the dual‐atom structures provides an appealing direction to develop advanced electrocatalysts for the CO2RR. [ABSTRACT FROM AUTHOR]

We report a thermodynamically driven metal diffusion strategy for the controlled synthesis of high-entropy alloy (HEA) nanocrystals using electrospun carbon nanofibers (CNFs) as nanoreactors. This conceptual pathway is resistant to high temperatures and produces a series of medium-entropy alloy (MEA) and HEA nanocrystals supported on CNFs by adjusting the numbers and kinds of elements. The FeCoNiCrMn/CNFs obtained the lowest overpotential of 345 mV at 50 mA cm−2 compared to MEA. The operando electrochemical Raman results indicate that the enhanced electron transfer from low-electronegativity Fe, Ni, Cr and Mn to the orbit of the Co atom makes Co a local negative charge center, leading to the decrease in absorption energy of OH. [ABSTRACT FROM AUTHOR]

A Cu 9 S 5 @MoS 2 core–shell heterostructure with controlled layers were synthesized through the combination of electrospinning technology and a chemical vapor deposition method via an in situ S vapor-assisted strategy. [Display omitted] Binary transition metal chalcogenide core–shell nanocrystals are considered the most promising nonprecious metal catalysts for large-scale industrial hydrogen production. Herein, we report a one-dimensional, space-confined, solid-phase strategy for the growth of a Cu 9 S 5 @MoS 2 core–shell heterostructure by combining electrospinning and chemical vapor deposition methods. The Cu 9 S 5 @MoS 2 core–shell nanocrystals were synthesized in situ on carbon nanofibers (Cu 9 S 5 @MoS 2 /CNFs) by an S vapor graphitization process. Tuning of the MoS 2 shell numbers can be controlled by changing the mass ratio of the Cu and Mo precursors. We experimentally determined the effects of the thickness of the MoS 2 shell on the electrocatalytic activity for the hydrogen evolution reaction (HER) in acidic and alkaline solutions. When the mass ratio is 3:1, the Cu 9 S 5 @MoS 2 /CNFs show the fewest MoS 2 shells with just 1–2 layers each and exhibit the best HER performance with small overpotentials of 116 mV and 114 mV in acidic and alkaline solutions, respectively, at a current density of 10 mA cm−2. The core shell structures, with their unique Cu-S-Mo nanointerfaces, could enhance the electron transfer and surface area, thus increasing the performance of the HER. This work provides a facile method to design unique core shell assemblies in one-dimensional nanostructures. [ABSTRACT FROM AUTHOR]

Due to the inherent sluggish kinetics of oxygen evolution reaction (OER), designing high-efficient and stable electrocatalysts is essential and urgent for the practical use of energy conversion devices. The transition-metal based layered double hydroxide (LDH) is considered as an alternative candidate with desired OER activity, while its catalytic performance is impeded by the limited active sites, poor conductivity and durability. Herein, the ultrafine and well-dispersed Ru nanoparticles doped NiFe LDH (Ru-NiFe-LDH) is designed as highly efficient electrocatalyst for OER. Benefiting from synergistic electronic modulation, as well as the abundant active interfaces, between Ru nanoparticles and NiFe LDH, Ru-NiFe-LDH shows superior electrocatalytic activity in alkaline electrolyte with a low overpotential of 256 mV at the current density of 50 mA cm−2. Moreover, the Ru-NiFe-LDH exhibits comparable activity toward oxygen reduction (ORR). As a concept verification, a homemade Zn-air battery assembled by Ru-NiFe LDH presents desired performance and stability under practical operating conditions. This work may broaden the family of advanced electrocatalysts for electrochemical energy conversion. The abundant active interfaces were constructed in ultrafine Ru nanoparticles doped NiFe LDH to promote electrocatalytic oxygen evolution in alkaline condition. [Display omitted] [ABSTRACT FROM AUTHOR]

• Ru SAs were in situ synthesized by the dynamic transformation from clusters. • The formation of Ru–N–C bonds plays an important role for anchoring the Ru SAs. • The transformation can be controlled by the treatment time and temperatures. • Ru SAs exhibit superior HER activity with overpotential of 34 mV (20 mA cm−2). The challenges for preparing metal single atoms (MSAs) catalysts are facile synthesis approaches and the suitable supports with strong coordination to stabilize MSAs. Herein, we reported a facile strategy to synthesize the Ru single atoms (Ru SAs) through the dynamic transformation from clusters to single atoms by combining the electrospun technology and NH 3 -assisted graphitization process. The small Ru nanoclusters (NCs) supported on carbon nanofibers (CNFs) were in situ converted into Ru SAs in N-doped CNFs under the NH 3 treatment. Through controlling the NH 3 treatment time and graphitization temperatures, the Ru nanocrystals exhibit a dynamic transformation from nanoclusters to single atoms. The results indicate that the Ru NCs with larger amounts of Ru SAs exhibit superior HER activity in alkaline media with low overpotential of 34 mV at 20 mA cm−2, which is even significantly better than commercial Pt/C catalysts. The mass activity of Ru SAs/NCNFs is about 390 A g−1 Ru at an overpotential of 100 mV, which is ~3.5 times higher than that of commercial Pt/C (110 A g−1 Pt). This strategy will provide a new way for the large-scale production of MSAs transformed from different metal nanoparticles or nanoclusters. [ABSTRACT FROM AUTHOR]