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Herein, a high performance bifunctional catalyst was prepared by inserting N‐doped nanomaterials into Ni−Co layered dihydroxides (NiCo‐LDH) nanoplates for high performance zinc‐air battery. By using self‐assembly of perylenetetracarboxylic dianhydride and dicyandiamide in the hydrothermal condition, a nitrogen‐containing super thin carbonaceous nanosheet is achieved after calcination. Then NCM inserted NiCo‐LDH nanoplates attached to nickel foam (NiCo‐LDH/NCM@NF) are synthesized by in‐situ production of NiCo‐LDH species on NCM wrapped NF. The specific NCM improves the conductivity, electroactive surface area and the ORR/OER bifunctional activity of NiCo‐LDH nanoplates. In addition, benefited from the formed rich oxygen vacancies, NiCo‐LDH/NCM@NF delivers the low OER overpotential (352 mV at 50 mA cm−2) and boosted ORR performance with a half‐wave potential of 0.765 V vs RHE. As the air cathode, the fabricated ZAB devices show a satisfactory capacity of 685 mAh g−1 and the energy density of 158 mW cm−2. [ABSTRACT FROM AUTHOR]

Active bifunctional electrocatalysts for both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are badly required for high‐efficiency zinc–air batteries (ZABs). Herein, a Fe‐alloyed MoNi nanohybrid (MoNiFe) as bifunctional catalyst is reported. The alloyed MoNiFe architecture with the decreased size compared with MoNi is obtained by a hydrothermal reduction method, which enhances the exposed active sites and promotes the charge transfer. Accordingly, MoNiFe exhibits good bifunctionality, with a positive half‐wave potential (0.896 V) near Pt/C (0.812 V) in ORR reaction and a low overpotential (0.295 V) similar to IrO2 (0.29 V) in OER process. The as‐derived rechargeable ZAB cells based on the bifunctional MoNiFe catalyst show the peak power density of 58 mW cm−2 with a high open‐circuit voltage of 1.319 V. Thus, this work paves a new alloying avenue for synthesizing effective bifunctional electocatalysts for ZABs. [ABSTRACT FROM AUTHOR]

Electrolysis of water is a promising reaction to produce the sustainable energy of hydrogen that proceeds commonly by assistance of a highly efficient catalyst. Now, the development of highly efficient and low‐cost electrocatalysts has stimulated increasing interest. Herein, a new composited electrocatalyst of MoxC embedded in N‐doped carbon nanosheets (MoxC@NCS) is successfully prepared from a self‐assembly route. Due to the expanded interlayers of carbon NCS and enhanced active defective sites induced by two‐materials compositing, the as‐synthesized MoxC@NCS affords splendid hydrogen evolution reaction (HER, overpotential of 160 mV), as well as remarkable oxygen evolution reaction (OER, overpotential of 360 mV) at 10 mA cm−2 in alkaline water splitting. In view of earlier excellent performances, the bifunctional MoxC@NCS catalyst shows a low cell voltage of 1.56 V at 10 mA cm−2 in overall water splitting. In addition, the MoxC@NCS exhibits an outstanding stability after long‐term electrochemical measurements. These findings extend the potential application of carbon‐supported non‐noble metallic catalysts, being of great significance in sustainable energy‐related fields. [ABSTRACT FROM AUTHOR]

2D composited nanosheets of Mo2C/CoMoS4 are synthesized by a hydrothermal approach to obtain a bifunctional water‐splitting electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in aqueous alkaline solution. Due to the richened defects formed on the 2D catalyst, the as‐derived Mo2C/CoMoS4 exhibits high activity. At 10 mA cm−2, the HER and OER overpotentials of the 2D Mo2C/CoMoS4 nanosheets are just 117 and 250 mV, respectively, with the corresponding Tafel slope of 90 and 75 mV dec−1, near to the commercial Pt/C and IrO2. X‐ray photoelectron spectroscopy proves the strong interactions between Mo2C and CoMoS4 and the Raman analysis certifies the presence of richened defects in Mo2C/CoMoS4. Moreover, the Mo2C/CoMoS4 possesses a long‐term catalytic stability, showing potential application in the water splitting. [ABSTRACT FROM AUTHOR]

Electrolysis of water is a promising method for production of the green-energy hydrogen, which is commonly assisted by high powerful catalyst. At present, developing low-cost and highly efficient electrocatalysts has attracted increasing attention. Herein, a novel composited catalyst of Zn x Ni 1-x S@Mo 2 C loaded on conductive carbon cloth (Zn x Ni 1-x S@Mo 2 C/CC) is successfully prepared by the hydrothermal method. Due to the abundant active sites of defect structures induced by the surface engineering, the prepared Zn x Ni 1-x S@Mo 2 C/CC shows outstanding electrocatalytic performances in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) of water splitting, with low overpotential of 230 mV and 150 mV at 10 mA cm−2, respectively. The Zn x Ni 1-x S@Mo 2 C/CC as an OER/HER bifunctional catalyst for overall water splitting affords a stable voltage of 1.56 V @current density of 10 mA cm−2. Moreover, the catalyst shows an outstanding stability after a series of electrochemical tests. This work expands the multi-field applications of carbon cloth-supported materials as efficient non-precious metal-based electrocatalysts, with great importance in sustainable energy-relative technologies. [Display omitted] • The active Zn x Ni 1-x S@Mo 2 C loaded on carbon cloth (Zn x Ni 1-x S@Mo 2 C/CC) is prepared by a simple hydrothermal method. • Excellent electrocatalytic performance in oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is shown. • The sample as an OER/HER bifunctional catalyst for full water splitting affords a stable voltage of 1.56 V at 10 mA cm−2. • The prepared Zn x Ni 1-x S@Mo 2 C/CC displays excellent stability. [ABSTRACT FROM AUTHOR]

The development of efficient active inexpensive metal catalysts for water electrolysis has been a promising way to produce hydrogen. Herein, an electrode composed of NiCo 2 O 4 nanoneedle and molybdenum carbide coated on carbon cloth (NiCo 2 O 4 /Mo 2 C/CC) is prepared based on the hydrothermal process. The CC enhances the electric conduction ability of the system. The heterojunction between Mo 2 C and NiCo 2 O 4 makes NiCo 2 O 4 nanoneedle diminished and leads to production of richened oxygen vacancies. Therefore, NiCo 2 O 4 /Mo 2 C/CC presents the low overpotential of 120 mV for hydrogen evolution reaction (HER) and 220 mV for oxygen evolution reaction (OER) at 10 mA cm−2 used in water splitting. Meanwhile, NiCo 2 O 4 /Mo 2 C/CC shows remarkable oxygen reduction reaction (ORR) performance. With NiCo 2 O 4 /Mo 2 C/CC used as catalyst in air cathode, the prepared Zn-air battery exhibits a capacity of 778 mAh g−1 and an energy density of 104 mW cm−2, showing promising applications to replace the expensive rare-metal catalysts. [Display omitted] • Catalyst of NiCo 2 O 4 nanoneedle on Mo 2 C-coated CC is prepared. • The heterojunction induces formation of more oxygen vacancies and enhanced catalytic activity. • The functional catalyst presents improved OER, HER and ORR performance. [ABSTRACT FROM AUTHOR]

• CoMoS 4 is successfully intercalated within Co layered metal oxides. • i-CoMoS 4 @Co-LMO has remarkable OER and ORR bifunctional performances. • Maximum power density produced by i-CoMoS 4 @Co-LMO-fabricated Zn-air battery reaches 960 mAh g–1/1104 Wh kg–1. • Abundant active sites and expanded interlayers from intercalation-induced structural variation improve ZAB performance. The heterolayer intercalation between layered double hydroxide (LDH) and other nanosheets is a vital way to tailor the interfacial electronic coupling and the crystal defects, for optimizing functionality of 2D nanosheets. In this work, the CoMoS 4 nanosheet-intercalated Co layered metal oxide (i-CoMoS 4 @Co-LMO) is synthesized by growth of CoMoS 4 in Co layered double hydroxide (CoLDH), followed by calcination. The intercalated CoMoS 4 enlarges the lattice spacing of Co-LMO and boosts oxygen vacancy of stacked nanosheets, and the produced i-CoMoS 4 @Co-LMO simultaneously shows exceptional bifunctional catalytic performances of oxygen evolution reaction and oxygen reduction reaction due to the enhanced mass transport pathways and the fostered catalytic sites. Accordingly, a large peak power density of 130 mW cm–2 and an excellent durability (over 270 cycles) are exhibited by Zn-air batteries based on i-CoMoS 4 @Co-LMO as electrocatalyst, with diffusion limited current -4.21 mA cm–2, half-wave potential of 0.77 V vs RHE and high capacity of 960 mA h g–1 at energy density of 1104 Wh kg–1. This work underscores a facile, low-cost and environmental-friendly strategy to synthesize bifunctional catalysts hold high potential as a practical zinc-air cathode. [Display omitted] [ABSTRACT FROM AUTHOR]

Carbon doped metallic compounds have attracted a great deal of interest due to their new synergistic properties and enhanced catalytic performance from the doped-element induced defects. In this paper, polyaniline (PANI) is used as the carbon source to dope molybdenum carbide, which is annealed at 1000 °C to be nitrogen-doped carbon coupled with Mo 2 C (NC@Mo 2 C). Through the XRD, SEM and TEM methods the prepared NC@Mo 2 C composite is thoroughly characterized. The NC@Mo 2 C composite illustrates two-dimensional nanoplate morphology, and shows low overpotential in hydrogen evolution reaction (HER, 0.04 V) and oxygen evolution reaction (OER, 0.13 V) in 1 M KOH solution. Tafel slopes of NC@Mo 2 C for HER and OER are 100 mV decade−1 and 99 mV decade−1, respectively, rather lower than pure Mo 2 C (HER: 130 mV decade−1 and OER: 126 mV decade−1). The Raman and XPS results show that it is the structural defects of Mo 2 C derived from NC doping that activate the reaction. Meanwhile, the NC doping and resulted defects enhance the conductivity of Mo 2 C, as well as endow NC@Mo 2 C nanoplates high electrochemical active surface area, facilitating the ion transfer, water absorption and gas desorption. The results of our work open up a new chance to design efficient non-noble metal-based catalysts for water electrolysis. [Display omitted] ● 2D nanoplates of nitrogen-doped carbon@Mo 2 C (NC@Mo 2 C) are synthesized by an annealing method. ● The NC@Mo 2 C shows low overpotential in HER (0.04 V) and OER (0.13V) in 1 M KOH solution. ● Tafel slopes of NC@Mo 2 C for HER and OER are 100mV decade-1 and 99 mV decade-1, respectively, rather lower than pure Mo 2 C. ● The Raman and XPS results show that the structural defects of Mo 2 C from NC doping diminish the activation energy. [ABSTRACT FROM AUTHOR]

• Smaller sized NiCo 2 O 4 nanoneedles are grown on thinner carbon filaments. • NiCo 2 O 4 nanoneedles phosphated illustrate a low OER overpotential. • The phosphated electrode displays an excellent long-term durability. • Cooperation of small-sized effect and heteroatomic doping plays the crucial role. Herein, greatly enhanced oxygen evolution reaction (OER) performances are obtained under the cooperation of small-sized morphological effect and heteroatomic doping activation. Firstly, three dimensional nickel cobaltite nanoneedle arrays with smaller diameters were directly grown on the thinner carbon filaments (CF) surface. Its derivative, the flexible NiCo 2 O 4 /CF-P is successfully fabricated by phosphating of NiCo 2 O 4 /CF. Promoted by the cooperation of small-sized effect and heteroatomic doping, the as-derived flexible NiCo 2 O 4 /CF-P exhibits the excellent electrocatalytic behaviors. When assessed as an electrode for the OER, the NiCo 2 O 4 /CF-P electrode illustrates a low overpotential of 191 mV at 10 mA cm−2 in 1.0 M KOH aqueous solution, and a rapid kinetic speed with the Tafel curve slope of 83 mV decade−1 slightly worse than IrO 2 , but much better than NiCo 2 O 4 /CF (108 mV decade−1) and CF (142 mV decade−1). In addition, the as-prepared NiCo 2 O 4 /CF-P electrode displays an excellent long-term electrochemical durability during a 30 h test. It is also found that the hydrogen evolution reaction (HER) activities of NiCo 2 O 4 /CF-P electrode are superior to those of NiCo 2 O 4 /CF electrodes, demonstrating that the nanoneedle arrays morphology and phosphorous doping are both beneficial to improve the active sites, enhance conductivity and facilitate electron transfer in the process of water splitting. [ABSTRACT FROM AUTHOR]