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In this study, carbon nanofibers (CNFs) embedding molybdenum carbide (Mo 2 C)/cobalt (Co)-molybdenum (Mo) bimetallic carbide heterostructure electrocatalysts (denoted as A-B/CNFs) were prepared via electrospinning and high-temperature carbonization. Owing to the synergistic interaction between Co 6 Mo 6 C 2 and Mo 2 C components, the catalyst activity is improved. Furthermore, the rich mesoporous structure and electrical conductivity of CNFs, accelerate the reaction kinetics. As a result, the optimized Co 6 Mo 6 C 2 -Mo 2 C/CNFs-1 has excellent bifunctional electrocatalytic activity. With the current density of 10 mA cm−2, the hydrogen evolution reaction (HER) overpotential is only 94 mV, and the oxygen evolution reaction (OER) overpotential is 295 mV in an alkaline electrolyte. Building an alkaline electrolyzer with Co 6 Mo 6 C 2 -Mo 2 C/CNFs-1 as the anode and cathode electrodes requires a low cell voltage of only 1.66 V to achieve the current density of 10 mA cm−2, while maintaining ideal durability. This research offers a versatile and effective approach to creating bimetallic-based monolithic hydrolysis electrocatalysts. [Display omitted] • Co 6 Mo 6 C 2 -Mo 2 C/CNFs were synthesized through a two-step method. • Co 6 Mo 6 C 2 -Mo 2 C/CNFs-1 exhibited bifunctional activity for water splitting. • Overpotentials of HER and OER are 94 mV and 295 mV to deliver 10 mA cm−2. • A cell voltage of only 1.66 V was needed for overall water splitting. [ABSTRACT FROM AUTHOR]

Exploring energy storage devices and hydrogen evolution reaction electrode materials with high efficiency electrocatalytic activity, high energy density and low cost has broad prospects, but there are still huge challenges. Compared with traditional energy storage devices, supercapacitors (SCs) are a new type of energy storage device with broad development prospects. However, their practical application is significantly limited by the energy density of electrode materials. The practical application of hydrogen evolution reaction (HER) is limited by the high cost and scarcity of Pt-based precious metal catalysts. It is essential to develop materials with stable structure, low cost and abundant reserves. Here, in this paper, CoS 2 and CoSe 2 composites embedded in carbon nanofibers (CNFs) (expressed as CoS 2 -CoSe 2 /CNFs) were synthesized by electrospinning combined with in-situ growth Zeolite Imidazolate Framework-67 strategy, carbonization and subsequent selenium sulfide process. When employed as the positive material in supercapacitors, a specific capacitance of 292.2 F g−1 is achieved at a current density of 1 A g−1. The specific capacitance of asymmetric supercapacitors (ASCs) assembled with CoS 2 -CoSe 2 /CNFs-5 as positive materials remains stable with no significant change observed in specific capacitance even after undergoing 10,000 cycles. At the same time, when a current density of 10 mA cm−2 is applied in a 0.5 M H 2 SO 4 electrolyte solution, an overpotential reading of 189 mV is observed. The evidence mentioned above showcases the significant capacity of this substance for application in electrochemical energy storage and conversion. • The synergy of different components regulates the electronic structure. • The as-obtained materials exhibited a good energy storage and conversion performance. • The retention of the ZIF-67 skeleton structure can increases the number of active sites. [ABSTRACT FROM AUTHOR]

The demands for highly efficient and low-cost electrochemically active materials are still urgent needs for the fields of electro-catalysis and supercapacitor. Herein, a facile strategy for preparing high-efficient bi-functional electrode material was reported. The electrode material was prepared through embedding Co 2 P nanoparticles in the binary co-doped carbon nanofibers (Co 2 P@N&P-CNFs). This unique structure can effectively prevent the Co 2 P from detaching and provide abundant active sites. Materials prepared in this work showed the superior hydrogen evolution reaction (HER) performance with overpotential of 192 mV at a current density of 10 mA cm−2 and remarkable stability for 20 h. Moreover, the asymmetric supercapacitor (ASC) was fabricated using the Co 2 P@N&P-CNFs as the positive electrode material and carbon nanofibers (CNFs) as the negative electrode material, which shows an outstanding cycle stability (91.5% of the initial capacitance is retained throughout 10,000 charge-discharge tests) and a high E of 22.31 Wh kg−1 at the P of 225.02 W kg−1 at 0.3 A g−1. This work offers an effective route in designing bi-functional active materials for HER and supercapacitor. A novel one-step strategy to synthesize Co 2 P encapsulated N,P dual doped carbon nanofibers (Co 2 P@N,P-CNFs) is developed via electrospinning technology followed by carbonization process. They can be as the bifunctional electrode materials for hydrogen evolution reaction (HER) and supercapacitor. As expected, the as-obtained Co 2 P@N,P-CNFs shows superior HER and supercapacitor performance. Most importantly, a high-performance asymmetric supercapacitor (ASC) is assembled with Co 2 P@N,P-CNFs and CNFs. Image 1 • Co 2 P embedded in N&P co-doped carbon fibers was fabricated by an effective method. • The materials were used as bifunctional materials for electrochemical application. • The as-obtained materials exhibited a good energy storage performance. [ABSTRACT FROM AUTHOR]

Transition metal iron-based catalysts are promising electrocatalysts for oxygen reduction reaction (ORR), and they have the potential to replace noble metal catalysts. The one-dimensional of carbon nanofibers with tubular structure can effectively promote the electrocatalytic activity, which facilitates electron transport. Herein, the Pt–Fe/CNFs were synthesized by electrospinning and subsequent calcination. Benefiting from the advantages of one-dimensional structure, Pt–Fe/CNFs-900 with fast electrochemical kinetics and excellent stability for ORR with excellent onset of 0.99 V, a low Tafel slope of 62 mV dec−1 and high limiting current density of 6.00 mA cm−2. Long-term ORR testing indicated that the durability of this catalyst was superior to that of commercial Pt/C in alkaline electrolyte. According to RRDE test, the ORR reaction process of Pt–Fe/CNFs-900 was close to four-electron transfer routes. • The Pt–Fe/CNFs were synthesized by electrospinning and subsequent calcination. • Pt–Fe/CNFs-900 with fast electrochemical kinetics and excellent stability for ORR. • The durability of this catalyst was superior to that of Pt/C in alkaline electrolyte. [ABSTRACT FROM AUTHOR]

The development of highly effective and non-precious electrocatalysts for the hydrogen evolution reaction (HER) remains highly desirable. In this work, we report a facile strategy using preoxidized fiber films as a precursor to prepare a flower-like Mo 2 C-based electrocatalyst for the HER, in which the pyrolysis of a mixture of urea and ammonium molybdate tetrahydrate during thermal treatment realized nitrogen doping. The N–Mo 2 C/CNFs-900 electrocatalyst exhibits excellent HER activity with a small overpotential of 119 mV at 10 mA cm−2 in an alkaline solution and the Tafel slope was calculated to be 106.9 mV dec−1. N-M-9 demonstrated long term stability over 24 h. With an increase in temperature, MoO 2 was gradually transformed into Mo 2 C and the formation of Mo 2 C was promoted upon nitrogen doping. This work provides a feasible approach to synthesize high performance HER electrocatalysts for renewable energy applications. The N–Mo 2 C/CNFs were fabricated by the preoxidized nanofibers as templates using a facile solvothermal and high temperature carbonization. The presence of urea plays an important role in the formation of Mo 2 C and promotes the crystalline transformation. [Display omitted] • N-doped Mo2C nanoparticles coated with carbon nanofibers were synthesized using a simple solvothermal method for the HER. • N–Mo 2 C/CNFs-900 exhibit excellent activity and stability in alkaline media. • The Mo2+ and N dopants in N–Mo 2 C/CNFs-900 facilitate the HER. [ABSTRACT FROM AUTHOR]

We synthesized a porphyrin-functionalized conjugated microporous polymer by a simple Schiff base reaction and used it as an artificial protective coating for the Zn anode of aqueous zinc ion batteries. Due to the electronegativity and hydrophobicity of the polymer, the protective coating not only effectively inhibits the growth of Zn dendrites and the generation of corrosion reactions, but also promotes uniform Zn deposition, thereby achieving a stable Zn anode. [Display omitted] • Conjugated microporous polymer (ZnTAPP-TFTA) is rich in F and N elements. • The ZnTAPP-TFTA coating significantly improves the stability of the Zn anode. • The assembled full cell shows impressive electrochemical performance. • Theoretical calculations confirm that ZnTAPP-TFTA can promote uniform Zn deposition. In this paper, a multifunctional porphyrin-functionalized conjugated microporous polymer (ZnTAPP-TFTA) coating was prepared to achieve a stable dendritic-free Zn anode. The chemical structure of ZnTAPP-TFTA is rich in F and N elements. Through the interaction with Zn2+ ions, the transfer kinetics of Zn2+ ion are improved, the two-dimensional diffusion of Zn2+ ion is limited, and the rapid desolvation of hydrated Zn2+ ion is promoted, which not only inhibits the generation of hydrogen evolution reaction and inert by-products, but also induces uniform Zn deposition. Therefore, the ZnTAPP-TFTA@Zn symmetric cell exhibits a stable cycle life of 1100 h in comparison to the bare Zn symmetric cell. In addition, the ZnTAPP-TFTA@Zn//Cu asymmetric cell can maintain a coulombic efficiency of 98.7 % after cycling for 800 h. What's more, the full battery assembled with NH 4 V 4 O 10 cathode has higher specific capacity and excellent cycle stability. The strategy of realizing dendritic-free Zn anode by constructing functionalized CMPs points out a new way for the study of stable AZIBs. [ABSTRACT FROM AUTHOR]