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Aqueous zinc‐ion batteries (ZIBs) hold significant promise for large‐scale energy storage. While considerable strides have been made in modifying separators, the challenge of developing dendrite‐free, corrosion‐resistant, and cost‐effective separators for achieving extended cycling performance of Zn anodes persists. In light of this, a TiO2 coating separator to mitigate interfacial corrosion and passivation reactions, thereby facilitating high‐performance ZIBs is designed. This study delves into the influence of the loading amount and crystal phase of the TiO2 coating layers on separator modification. Zn symmetric cells employing the anatase TiO2‐modified glass fiber (A‐TiO2@GF) separator demonstrate superior Zn2+ ion transport kinetics in a mild ZnSO4 electrolyte, ensuring sustained long‐term stability and uniform Zn deposition. Furthermore, the reduced hydrogen evolution reaction (HER) activity of A‐TiO2 coatings curbs H+ ion migration, minimizing interfacial corrosion and HER. Consequently, the assembled Zn||CaV8O20 zinc‐ion full cells demonstrate outstanding long‐term durability and impressive specific capacity, boasting a discharge capacity of 142 mAh g−1 after 1000 cycles. This work introduces a straightforward interface engineering strategy for creating efficient separators in zinc‐ion batteries, promoting uniform Zn deposition. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries (AZIBs) have stimulated extensive attention due to their environmental friendliness and low cost. Unfortunately, the inevitable dendrite growth and corrosion on the zinc (Zn) anode severely hinder the practical application of AZIBs. Herein, an amino acid containing an imidazole group is introduced as an effective additive to address these issues. The dynamic conversion of amino acid and protonated amino acid creates a pH buffer function that regulates solution pH in real time, inhibits hydrogen evolution reaction (HER), and eliminates notorious by‐products. In addition, the protonated amino acid is preferentially adsorbed on the Zn anode, preventing contact of the active water with the Zn surface and promoting homogeneous Zn deposition. Thus, the amino acid‐based electrolyte promotes dendrite free plating/stripping with a Coulombic efficiency up to 99.67% and cycle lifetime of 2600 h. In particular, a depth of discharge of up to 87% can be achieved with an ultra‐high areal capacity of 24 mAh cm−2. The developed Zn||CVO full cell also exhibits better electrochemical performance than that without additives. This work provides an effective and convenient approach for safe and efficient Zn‐ion batteries. [ABSTRACT FROM AUTHOR]

In order to alleviate the energy crisis and propel a low-carbon economy, hydrogen (H2) plays an important role as a renewable cleaning resource. To break the hydrogen evolution reaction (HER) bottleneck, we need high-efficiency electrocatalysts. Based on the synergistic effect between bimetallic oxides, hierarchical mesoporous CoNiO2 nanosheets can be fabricated. Combining physical representations with electrochemical measurements, the resultant CoNiO2 catalysts present the hierarchical microflowers morphology assembled by mesoporous nanosheets. The ultrathin two-dimensional nanosheets and porous surface characteristics provide the vast channels for electrolyte injection, thus endowing CoNiO2 the outstanding HER performance. The excellent performance with a fewer onset potential of 94 mV, a smaller overpotential at 10 mA cm−2, a lower Tafel slope of 109 mV dec−1 and better stability after 1000 cycles makes CoNiO2 better than that of metallic Co and metallic Ni. [ABSTRACT FROM AUTHOR]

Summary: The development of highly active, robust and cost‐effective noble metal‐free electrocatalysts for hydrogen evolution reaction (HER) in alkaline solution remains a severe challenge. In this work, a hollow structure CoSe2‐FeSe2 heterojunction electrocatalyst (denoted by "(Co,Fe)Se2") was designed by a simple anion exchange reaction and selenization. Benefiting from the unique hollow structure, the (Co,Fe)Se2 catalyst accelerates diffusion of electrolyte, besides, the CoSe2‐FeSe2 heterojunction could provide rapid interfacial charge transportation and more active sites for the HER reaction. The (Co,Fe)Se2 electrode material exhibits good performance for HER in 1 M KOH electrolyte. It needs an overpotential of 124 mV to obtain a current density of 10 mA cm−2, and the Tafel slope is 65 mV dec−1. Besides, (Co,Fe)Se2 has a smaller charge transfer resistance compared with CoSe2. At the same time, it has relatively large electrochemical active surface area due to the porosity. Most importantly, the (Co,Fe)Se2 electrode displays good stability in alkaline conditions for 15 hours, the linear sweep voltammetry curves are almost coincident before and after 1000 cycles, the overpotential with current density of 10 mA cm−2 increased by only 9.76% after 5000 cycles of CV. It shows great application potential in HER. [ABSTRACT FROM AUTHOR]

Herein, a three-dimensional (3D) Ni/Fe bimetallic organic framework (MOF-Ni@MOF-Fe) with a structure of rhombus blocks on nanosheets is synthesized on Ni foam by a 2-step solvothermal method. After sulfide reaction, MOF-Ni@MOF-Fe–S is vulcanized by MOF-Ni@MOF-Fe with a structure of interwoven and folding nanosheets. Meanwhile, Ni3S2 is formed under the influence of iron. This special structure makes MOF-Ni@MOF-Fe–S to expose more active sites. MOF-Ni@MOF-Fe–S shows superior urea oxidation reaction (UOR) and hydrogen evolution reaction (HER) performance. When MOF-Ni@MOF-Fe–S is used as UOR and HER catalysts, it has low potentials of 1.347 V (vs. RHE) at 10 mA cm−2 and 0.145 V (vs. RHE) at 10 mA cm−2 in 1.0 M KOH with 0.5 M urea, respectively. MOF-Ni@MOF-Fe–S as a bifunctional electrode is assembled as an alkaline urea electrolyzer, showing catalytic activity at a low cell voltage of 1.539 V at 10 mA cm−2 and excellent stability during 10 h chronopotentiometry analysis. [ABSTRACT FROM AUTHOR]

The adoption of effective, minimal, and versatile electrocatalysts for water splitting to generate hydrogen fuels is of critical importance. The bulk of newly described materials have considerable onset potential, but their electrocatalytic activity is limited by weak electrical conductivity and a limited range of catalytic sites. The combination of a few precious metals added with transition metal-based compounds is a novel and captivating approach. Herein, cobalt ferrite oxide (Co 2 FeO 4) @ palladium oxide (PdO) nanostructures have been prepared through the combined use of hydrothermal and ultraviolet (UV) irradiation techniques. For hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics, the modified composition offers a high concentration of active sites, improved electrical conductivity, and stability. The Co, Fe, and Pd ions at the composite system's interface may affect the adsorption energy of reaction intermediates synergistically, enabling the process to continue with less potential. The electrocatalyst Co 2 FeO 4 @PdO demonstrates an excellent bifunctional approach to electrochemical water splitting (EWS) for HER and OER in alkaline medium. As-prepared electrocatalyst shows an overpotential value of 269 and 259 mV for HER and OER at 10 and 20 mA/cm2 current densities respectively. The low charge transfer resistance values such as 72.2 and 62.4 Ω and durability for 48 h has been observed toward HER and OER , support this material as an efficient and durable electrocatalyst for energy conversion systems. [Display omitted] • Effective Cobalt–Iron-Ferrite oxides and Palladium-oxide based bifunctional electrocatalyst. • Promising activity for HER and OER with lower Tafel slope values in the alkaline media. • Longer stability and durability for 20 h. [ABSTRACT FROM AUTHOR]

[Display omitted] Rechargeable metal batteries such as non-aqueous Li metal batteries and aqueous Zn metal batteries have received increasing attention due to the benefits of the high-energy metal anode. However, the dendric growth on the metal anode extremely leads to restricted cycling performance and potential safety issues. Herein, the MXene-modified conductive framework (MCF) is designed and fabricated as a universal current collector of anode for non-aqueous Li metal batteries and aqueous Zn metal batteries to suppress the dendric Li and Zn growth. The MCF exhibits the merits of good lithiophilicity and zincophilicity, enables an easy Li/Zn nucleation process, and possesses high plating/stripping reversibility. After plating Li/Zn, MCF@Li and MCF@Zn realize a dendrite-free surface, facilitating Li/Zn plating/stripping kinetics. The MCF@Li and MCF@Zn symmetric cell shows a low overpotential of 13 mV at 1 mA cm−2 after 900 cycles and 64 mV at 5 mA cm−2 after 750 cycles (1 mAh cm−2), respectively. Furthermore, the non-aqueous MCF@Li||LiFePO 4 full cells and the aqueous MCF@Zn||active carbon capacitors are assembled and present stable cycling ability and improved rate performance with low polarization. This work provides a universal current collector strategy to meet the requirements of non-aqueous and aqueous metal anodes, which may inspire more designs for metal-based energy storage systems. [ABSTRACT FROM AUTHOR]

Development of efficient, low cost and multifunctional electrocatalysts for water splitting to harvest hydrogen fuels is a challenging task, but the combination of carbon materials with transition metal-based compounds is providing a unique and attractive strategy. Herein, composite systems based on cobalt ferrite oxide-reduced graphene oxide (Co 2 FeO 4) @(rGO) using simultaneous hydrothermal and chemical reduction methods have been prepared. The proposed study eliminates one step associated with the conversion of GO into rGO as it uses direct GO during the synthesis of cobalt ferrite oxide, consequently rGO based hybrid system is achieved in-situ significantly, the optimized Co 2 FeO 4 @rGO composite has revealed an outstanding multifunctional applications related to both oxygen evolution reaction (OER) and hydrogen counterpart (HER). Various metal oxidation states and oxygen vacancies at the surface of Co 2 FeO 4 @rGO composites guided the multifunctional surface properties. The optimized Co 2 FeO 4 @rGO composite presents excellent multifunctional properties with onset potential of 0.60 V for ORR, an overpotential of 240 mV at a 20 mAcm−2 for OER and 320 mV at a 10 mAcm−2 for HER respectively. Results revealed that these multifunctional properties of the optimized Co 2 FeO 4 @ rGO composite are associated with high electrical conductivity, high density of active sites, crystal defects, oxygen vacancies, and favorable electronic structure arisinng from the substitution of Fe for Co atoms in binary spinel oxide phase. These surface features synergistically uplifted the electrocatalytic properties of Co 2 FeO 4 @rGO composites. The multifunctional properties of the Co 2 FeO 4 @ rGO composite could be of high interest for its use in a wide range of applications in sustainable and renewable energy fields. Illustration of multifunctional surface properties of Co 2 FeO 4 @rGO composite. [Display omitted] • In situ rGO and cobalt ferrite oxide (Co 2 FeO 4 @rGO) composite is prepared. • The synthesized composite exhibited tri-functional water catalysis. • Composite shows an overpotential of 240 mV at a 20 mAcm−2 for OER. • A long term durability of 48 h was also demonstrated by composite material. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of efficient catalysts for hydrogen evolution reaction (HER) from water splitting is one of the most promising strategies to achieve the goal of peak carbon dioxide emissions and carbon neutrality. Herein, Ru nanoclusters decorated MoSe 2 nanosheets supported on a Crepis tectorum fluff biomass-derived hollow carbon tube (Ru-MoSe 2 /CMT) are prepared as the HER catalysts in both alkaline and acidic conditions. The Ru modification induces the transformation of MoSe 2 from 2H phase to 1T phase. Benefiting from the strong water dissociation ability of Ru, Ru-MoSe 2 /CMT exhibits a low overpotential of 70 mV with a Tafel slope of 39 mV dec-1 in 1 M KOH. Furthermore, the assembled Ru-MoSe 2 /CMT || RuO 2 system with a low cell voltage of 1.54 V at 10 mA cm−2 exhibits outstanding overall water splitting performance superior to Pt/C || RuO 2 system. The Ru-MoSe 2 /CMT || RuO 2 system also achieves the excellent stability of up to 30 h in 1 M KOH. The synergy effect between Ru and MoSe 2 , as well as the improved electron transfer kinetics provided by the biomass-derived carbon substrate together contribute to the excellent HER activity of Ru-MoSe 2 /CMT. [ABSTRACT FROM AUTHOR]

[Display omitted] • RuNi 1 Co 1 alloy nanoparticles embedded in the hollow carbon tubes with a mosaic structure was prepared. • The DFT calculations indicate that the addition of Ru could optimize the hydrogen adsorption free energy of Ni and Co sites. • RuNi 1 Co 1 @CMT exhibits considerable HER and OER activities, and a low cell voltage was required for the overall water splitting system. • RuNi 1 Co 1 @CMT || RuNi 1 Co 1 @CMT overall water splitting system can be driven by a solar panel, which realized green and sustainable hydrogen production. The development of efficient bifunctional catalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for reducing the cost of hydrogen production by water splitting. Herein, hollow microtubes composed of RuNi 1 Co 1 alloy nanoparticles uniformly embedded in the carbon matrix (RuNi 1 Co 1 @CMT) are prepared through a simple impregnation followed by reduction. Benefiting from the unique mosaic structure and the synergistic effect between Ru and NiCo, RuNi 1 Co 1 @CMT achieves more exposed active sites and improved reaction kinetics. As a consequence, RuNi 1 Co 1 @CMT exhibits considerable catalytic activities with the overpotentials of 78 mV for HER and 299 mV for OER at 10 mA cm−2 in 1 M KOH. In addition, RuNi 1 Co 1 @CMT exhibits excellent stability for up to 30 h in both HER and OER processes at 20 mA cm−2, which is attributed to the protection of the RuNi 1 Co 1 alloy particles by the carbon layer. Furthermore, the assembled RuNi 1 Co 1 @CMT || RuNi 1 Co 1 @CMT overall water splitting system shows a cell voltage of 1.58 V at 10 mA cm−2. The density functional theory (DFT) calculations indicate that the addition of Ru can optimize the hydrogen adsorption free energy of Ni and Co sites. Finally, a solar panel-driven water splitting device is built, which can realize green and sustainable hydrogen production. The fabrication of RuNi 1 Co 1 @CMT provides a new way for the preparation of effective alloy nanomaterials for energy storage and conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoSe 2 -MoSe 2 (1–1)/rGO has good HER activity in both acidic and alkaline media. • The CoSe 2 -MoSe 2 (1–1) nanosheets uniformly decorate the rGO matrix. • DFT results verify CoSe 2 -MoSe 2 (1–1) heterostructure owns small band gap and ΔG H*. • The rGO matrix and heterojunction structure improve the electronic conductivity. It is important to develop novel energy to solve energy shortage and environmental problems. Hydrogen evolution reaction (HER) is envisaged as a viable technology that can be used to develop sustainable clean energy. Herein, we report a catalyst with CoSe 2 -MoSe 2 heterostructure grown on reduced graphene oxide with an optimum Co/Mo proportion of 1:1 (CoSe 2 -MoSe 2 (1–1)/rGO). It exhibits good HER activities in both acidic and alkaline conditions. The CoSe 2 -MoSe 2 (1–1)/rGO shows an overpotential of 107 mV at 10 mA cm−2 with a Tafel slope of 56 mV dec−1 under acidic condition. Meanwhile, CoSe 2 -MoSe 2 (1–1)/rGO also presents an overpotential of 182 mV at 10 mA cm−2 and with a Tafel slope of 89 mV dec−1 under alkaline condition. These impressive performances of the catalyst are mainly due to the excellent electronic transmission capability of rGO and the abundant active sites of CoSe 2 -MoSe 2 heterostructure as well as the optimized hydrogen adsorption energy of CoSe 2 -MoSe 2 interface. The design of CoSe 2 -MoSe 2 (1–1)/rGO provides a meaningful guide for manufacturing electrode in energy storage and conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • FeSe 2 -MoSe 2 (1-1)/rGO has good HER activity in both acidic and alkaline media. • FeSe 2 -MoSe 2 (1-1)/rGO has well stability in both acidic and alkaline media. • On the morphology, FeSe 2 -MoSe 2 nanoparticles uniformly decorate the rGO matrix. • DFT results verify the FeSe 2 -MoSe 2 (1-1)/rGO owns small work function. It is of great significance to develop inexpensive and high-efficiency electrocatalysts for the hydrogen evolution reaction (HER). In this work, we synthesized iron molybdenum selenide (FeSe 2 -MoSe 2) loaded on reduced graphene oxide (FeSe 2 -MoSe 2 /rGO) by a one-step hydrothermal method. We further optimized the Fe/Mo ratio and determined the best ratio to be 1-1. In acidic (or alkaline) solution, the optimized FeSe 2 -MoSe 2 (1-1)/rGO has a small Tafel slope of 55 (or 80) mV dec−1 and needs an overpotential of 101 (or 178) mV to achieve 10 mA cm−2. These good properties are mainly due to the structure of bimetallic selenides combining rGO. Moreover, rGO enhances the electrical conductivity. Furthermore, the synergistic effect between FeSe 2 -MoSe 2 (1-1) and rGO results in better HER performance. Density functional theory (DFT) calculation proves that FeSe 2 -MoSe 2 (1-1)/rGO has a small work function. Based on our reasonable design and analysis, FeSe 2 -MoSe 2 (1-1)/rGO is expected to be an efficient and robust catalyst for large-scale applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Electrocatalytic water splitting used for generating clean and sustainable hydrogen (H 2) can be very promising to address current energy shortage and associated environmental issues. However, this methodology is severely impeded by the tardy oxygen evolution reaction (OER). Hence, designing a preferable kinetics and thermodynamics oxidation reaction that supersede OER is very significant for the energy-saving production of H 2. Herein, hollow needle-like copper cobalt sulfide was constructed on carbon cloth (CuCo 2 S 4 /CC) as a bifunctional electrocatalyst to accelerate H 2 generation and simultaneously convert ethanol into value-added acetic acid. Thanks to the synergistic effect and unique structure of Cu and Co, CuCo 2 S 4 /CC displays superior catalytic activity and durability in ethanol oxidation reaction (EOR) with a low potential of 1.38 V vs. RHE (@10 mA cm−2). Meanwhile, it exhibits excellent hydrogen evolution reaction (HER) performance. The homemade CuCo 2 S 4 /CC//CuCo 2 S 4 /CC ethanol–water electrolyser only demands a voltage of 1.59 V to deliver 10 mA cm−2, 150 mV less than that used for ordinary water splitting. This shows that the ethanol–water electrolyser elaborated here holds encouraging potential in the energy-saving production of H 2 and oxidation of ethanol into value-added acetic acid. This present work may open the way for the rational design of other electrocatalysts for efficient biomass oxidation reaction and relevant H 2 production applications. [ABSTRACT FROM AUTHOR]

Integrating transition metal complexes with carbon-based materials, especially graphene, is a useful strategy for synthesizing effective hydrogen evolution catalysts. Herein, we report a design of hollow hexagonal NiSe–Ni 3 Se 2 nanosheets grown on reduced graphene oxide (NiSe–Ni 3 Se 2 /rGO) by a simple hydrothermal method as an effective catalyst for hydrogen evolution reaction (HER) in the full pH range. In 0.5 M H 2 SO 4 , the NiSe–Ni 3 Se 2 /rGO possesses 112 mV to achieve 10 mA cm−2 and a small Tafel slope (61 mV dec−1). In 1.0 M PBS and 1.0 M KOH, the overpotentials are 261 and 188 mV at 10 mA cm−2, and Tafel slopes are 103 and 92 mV dec−1, respectively. Meanwhile, it owns good cycle stability and durability over 20 h in the whole pH range (0-14). In all solutions, the HER performance of NiSe–Ni 3 Se 2 /rGO is better than that of NiSe–Ni 3 Se 2. This is because the rGO substrate accelerates the electron transfer and improves the electrical conductivity, increasing HER activity of catalyst. • The hollow hexagonal NiSe-Ni3Se2 nanosheets uniformly decorate the rGO. • The hollow structure exposes more active sites and transport pathways. • The hybrid material exhibits superior performance for HER in all pH media. • The stability of the composite is good under a variety of pH conditions. [ABSTRACT FROM AUTHOR]

The electrochemical nitrate reduction reaction (eNO 3 RR) to ammonia (NH 3) is a promising alternative method to the Haber-Bosch process that requires high temperature and pressure. In this contribution, the integrated Co 3 O 4 nanowire arrays on Ni foam (Co 3 O 4 /NF) are reported to exhibit the outstanding performance with a high NH 3 yield rate of 117.01 mg h−1cm−2, a superior NH 3 Faradaic efficiency of 99.28 %, a high effective current density of 1475.71 mA cm−2, and a good operation durability during 40 consecutive recycling tests (40 h) in 1.0 M NaOH (0.1 M NaNO 3). The high-valence metal cations as electron-deficient centers can act as Lewis-acid sites, favorably interacting with the Lewis base NO 3 −, and accordingly boosting the NO 3 − adsorption and activation. Moreover, the in-situ growth array configuration provides the substantial active sites and constructs a fast electron-transport channel, thus facilitating the conversion of NO 3 −-to-NH 3. Density functional theory (DFT) calculations also reveal that the Co atoms as the active sites are preferred to adsorb NO 3 −, implying that the NO 3 − electroreduction dominates the cathodic reaction rather than hydrogen evolution reaction. This study provides a viable method to design integrated electrodes with enhanced eNO 3 RR activity and selectivity, which might have broad prospects in the application of renewable energy. The efficient nitrate-to-ammonium conversion is achieved by the integrated Co 3 O 4 nanowire arrays rich in electron-deficient centers. Benefitted from the massive exposed active sites, improved conductivity and charge transfer efficiency, as well as the abundant Lewis acid sites, Co 3 O 4 nanowire arrays present the brilliant nitrate electroreduction performance, including 117.01 mg h−1 cm−2 NH 3 yield rate and 99.28 % Faradaic efficiency in 1.0 M NaOH with 0.1 M NO 3 −. [Display omitted] • High-valence metal cations are favorable to boost NO 3 − adsorption and activation. • Integrated nanowire arrays configuration can provide massive exposed active sites. • Co 3 O 4 /NF can provide a fast electron-transport channel and excellent conductivity. • Co 3 O 4 /NF presents the considerable activity and stability towards eNO 3 RR process. [ABSTRACT FROM AUTHOR]

Seeking the efficient and robust electrocatalysts necessarily enhances performance of hydrogen evolution reaction (HER). Increasing the surface active sites is a means to improve the performance. Herein, we use the Ni 0·85 Se anchored on reduction of graphene oxide (Ni 0·85 Se/rGO) hybrid material skillfully established by one-step facile hydrothermal method as a robust and stable electrocatalyst applying to hydrogen evolution reaction (HER). In terms of morphology, Ni 0·85 Se nanospheres composed of many nanosheets are uniformly distributed on the graphene sheet layer. We also detailedly analyze its properties. Based on the interaction between Ni 0·85 Se and rGO, and the roles of graphene are as a substrate to heighten conductivity, possesses more active surface area by limiting growth of Ni 0·85 Se, and increases dispersion for exposing more active surface area and enlarge ion/electron transfer rate. In HER, the Ni 0·85 Se/rGO catalyst displays the overpotential of 128 mV with a common current density of 10 mA cm−2, a small Tafel slope of 91 mV dec−1, an extremely low onset potential of 37 mV, outstanding stability that a high current retention of 97.7% after 1000 cycles and well long-term stability for 18 h, outperforming the capability of Ni 0·85 Se nanospheres in alkaline solution for HER. The above results indicate that the Ni 0·85 Se/rGO hybrid material is a good HER ability and non-noble metal electrocatalyst has potential value in HER. • The Ni 0.85 Se nanospheres uniformly decorate the rGO sheets. • The Ni 0.85 Se/rGO electrocatalyst possesses more active surface area. • The stability of the composites can reach 97.7%. • The hybrid material exhibits superior performance for HER. [ABSTRACT FROM AUTHOR]

The Mo 2 C@C catalyst was prepared by the calcination method under the argon gas flow of the activated walnut shell-ammonium heptamolybdate hybrid powder mixture, enhancing the electrocatalytic hydrogen evolution process. • The waste walnut shell powder was chosen as the carbon source for HER catalysts. • The walnut shell powders derived carbon matrix can enhance the electron transfer. • The open pores can facilitate electrolyte permeation and hydrogen release. Herein, we choose the waste walnut shell as the carbon source, and ammonium heptamolybdate as the molybdenum source to prepare the β-Mo 2 C catalyst supported on carbon matrix (Mo 2 C@C) by the calcination method for hydrogen evolution reaction (HER). The open pores in the porous Mo 2 C nanoparticle clusters can facilitate electrolyte permeation and hydrogen molecules release as well as the carbon matrix can enhance the conductivity. As a result, the optimal Mo 2 C exhibits an efficient HER performance, with an overpotential of 140 mV at 10 mA cm−2 and a Tafel slope of 63 mV dec−1 as well as excellent electrochemical stability. The strategy changing waste walnut shell into the effective catalysts sets an example for the searching and designing rational energy materials. [ABSTRACT FROM AUTHOR]

In this paper, we report the three-dimensional self-supported CoMoO 4 nanosheet clusters on the nickel foam (denoted as CoMoO 4 /NF) by a facile hydrothermal-calcination method for efficient hydrogen generation. As a result, the freestanding CoMoO 4 electrode exhibits an efficient electrochemical activity towards hydrogen evolution reaction, showing overpotentials as low as 68 and 178 mV at current densities of 10 and 100 mA cm−2 in the alkaline condition (1 M KOH), respectively, a Tafel slope value of 82 mV per decade. Moreover, the electrode exhibits remarkable electrochemical durability for 1000 cycles. Significantly, the water splitting electrolyzer assembled with CoMoO 4 /NF || NiFe LDH/NF (the nickel iron layered double hydroxide supported on the nickel foam) system achieved 20 mA cm−2 at 1.63 V, showing the CoMoO 4 /NF is promising for practical water splitting applications. • The low-cost and effective transition metal oxide of CoMoO 4 was adopted for hydrogen generation. • The open nanostructure can facilitate permeating electrolyte as well as releasing hydrogen molecules. • The crosslinked nanosheet clusters can offer amounts of active sites for hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

Abstract At present, there is an urgent need for plentiful non-noble metal catalyst to substitute for valuableness platinum based metal catalyst in electrochemical water splitting. Here, we fabricated a three-demensional (3D) Ni Co NiCo 2 O 4 nanosheets electrocatalyst that directly grew on Ni foam firstly and then were reduced in 0.1 mol dm−3 sodium borohydride solution. This electrode exhibited high activity in 1.0 mol dm−3 KOH solution with an onset potential of ∼40 mV and a tafel slope of 77 mV dec−1. Furthermore, the Ni Co NiCo 2 O 4 /NF electrode showed a splendid durability during long-playing electrochemical test. Our work may provide an inexpensive, easy-to-obtain and excellent catalyst candidate for future electrolytic water research and industry studies that may involve hydrogen applications in the future. Highlights • The Ni Co NiCo 2 O 4 /NF is an inexpensive, easy-to-obtain and excellent electrode. • When the current density up to 10 mA cm−2 requires an overpotential 125 mV. • Metallic Ni and Co core enhance the electrode activity. [ABSTRACT FROM AUTHOR]

Porous Ni 2 P nanoflower supported on nickel foam (Ni 2 P@Ni foam) electrodes are synthesized via a simple hydrothermal growth strategy accompanied with further phosphating treatment. The prepared electrodes are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). Electro-catalytic performances towards urea electro-oxidation are tested by cyclic voltammetry (CV), chronoamperometry (CA) coupled with electrochemical impedance spectroscopy (EIS). By phosphating Ni(OH) 2 precursor, the final obtained Ni 2 P@Ni foam electrode presents a porous Ni 2 P nanoflower structure within abundant porosity, and so exposes a large amount of electro-catalytic active sites and electronic transmission channels to accelerate the interfacial reaction. Compared with Ni(OH) 2 @Ni foam precursor, the Ni 2 P@Ni foam catalyst exhibits more excellent electro-catalytic activity as well as lower onset oxidation potential. Remarkably, the Ni 2 P@Ni foam catalyst reaches a peak current density of 750 mA cm −2 with an onset oxidation potential of 0.24 V (vs. Ag/AgCl) accompanied by an excellent stability in 0.60 M urea with 5.00 M KOH solutions. Benefiting from the unique porous nanosheet structure, the as-synthesized Ni 2 P@Ni foam catalyst performs a highly enhanced catalytic behavior for alkaline urea electro-oxidation, indicating that the material can be hopefully applied in direct urea fuel cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • A modified guar gum layer inhibits the Zn dendrites growth. • Breaking intramolecular hydrogen bonds prevents the HER. • RFH-GG@Zn symmetric cell demonstrates 2500 h cycling life. • AC||RFH-GG@Zn capacitors present cycling stability of 60,000 cycles. Zn-based energy storage devices such as Zn ion hybrid capacitor (ZICs) and Zn ion batteries (ZIBs) have attracted extensive attention due to the advantages of low cost, chemical stability, and high capacity of Zn metal anode. However, the Zn anode faces the difficulties of inevitable dendrite growth and hydrogen evolution reaction (HER) during cycling. Herein, we construct guar gum film, as artificial solid electrolyte interphase, on the Zn metal to suppress the dendrite grown and promote Zn deposition. Meanwhile, the Zn2+ desolvation process is enhanced by regulating the hydrogen bonding inside the film. As a result, the Zn anode coated with guar gum with rich free hydroxyl groups (RFH-GG@Zn) remains a low overpotential (45 mV) after an alternant plating/stripping process for more than 2,500 h. The application of RFH-GG@Zn promotes the cycling performance and rate ability of ZICs and ZIBs. This work aims to prepare high-performance Zn metal anodes by reducing intramolecular hydrogen bonding to enhance the protective effect of the coating on Zn anodes. [ABSTRACT FROM AUTHOR]

The exploitation of efficient and low-cost electrocatalysts for the oxygen evolution reaction (OER) is the key to the industrialization of the hydrogen production technology from water splitting. Herein, Ni 1 Fe 2 @Fe 2 O 3 composites with core-shell structure embedded in Metaplexis japonica fluff-derived carbon microtube matrix (Ni 1 Fe 2 @Fe 2 O 3 @C) are prepared by nitrate soaking and subsequent high-temperature calcination, which are used to catalyze the OER. The existence of carbon matrix greatly prevents the agglomeration of metal particles and creates an efficient electron transfer path for OER. The synergy among the carbon matrix, Ni 1 Fe 2 core and Fe 2 O 3 shell together enhances the OER performance, thus endowing Ni 1 Fe 2 @Fe 2 O 3 @C with the considerable catalytic activity with the overpotential of 271 mV at 10 mA cm−2 and a Tafel slope of 78 mV dec−1. Ni 1 Fe 2 @Fe 2 O 3 @C also shows good stability due to the double protection of metal particles by biomass carbon matrix and ultrathin Fe 2 O 3 shell. The water splitting device composed of Pt/C as the cathode and Ni 1 Fe 2 @Fe 2 O 3 @C as the anode exhibits water splitting activity close to that of Pt/C || RuO 2 system in alkaline medium, and the stability retention rate of the system reaches to 93 % after 30 h electrolysis. [Display omitted] • Ni 1 Fe 2 @Fe 2 O 3 composites with core-shell structure embedded in Metaplexis japonica fluff-derived carbon microtube matrix were prepared. • The existence of carbon matrix greatly prevents the agglomeration of metal particles and creates an efficient electron transfer path for OER. • Ni 1 Fe 2 @Fe 2 O 3 @C exhibits considerable catalytic activity with the low overpotential for OER. [ABSTRACT FROM AUTHOR]

The design of inexpensive bifunctional electrocatalysts with excellent catalytic activity is crucial for the cost reduction from water splitting. As a kind of biomass with hollow tubular structure, Metaplexis japonica fluff is expected to be a natural substrate for the growth of nanostructured electrocatalysts. Herein, nanowire-like NiCo precursors are grown on Metaplexis japonica fluff biomass substrates by hydrothermal method, which are then converted into carbon microtube supported NiCoP-NiS 2 composites (NiCoP-NiS 2 /CMT) by low-temperature phosphorization and sulfidation treatment. As expected, the biomass substrate provides a guiding role for the growth of NiCoP-NiS 2 nanowires, which is conducive to expose more active areas and promote charge transfer during the reaction. As a result, the obtained NiCoP-NiS 2 /CMT exhibits good electrocatalytic performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 M KOH, which only requires overpotentials of 134 and 308 mV at 10 mA cm−2, respectively. In addition, the constructed symmetric water splitting device exhibits a cell voltage of 1.62 V at 10 mA cm−2, and it also displays good stability during the 24 h test. [Display omitted] [ABSTRACT FROM AUTHOR]

Designing earth-abundant hydrogen evolution reaction (HER) electrocatalysts with superior performance and eminent stability is the key to the practical production of high purity hydrogen. In the present work, Mn oxides with various valence state complex Fe–Ni sulfide (Mn x O y @FNS) heterogeneous materials were successfully fabricated through a feasible two-step hydrothermal process and can be directly used as active and efficient HER electrodes in alkaline media. This binder-free and defect-rich catalyst barely requires 105 and 365 mV to achieve −10 and −500 mA cm−2, respectively. Profiting from the disordered structure and the efficient interfacial effects between Mn oxides and Fe–Ni sulfide (FNS), this heterogeneous catalyst reveals sufficient electroactive sites, ample active edges and optimal electroconductivity. Additionally, during the 20 h HER reaction, the Mn x O y @FNS electrode exhibits outstanding durability. • Interlaced and plicated nanostructure provides sufficient exposed edge. • The disordered structure in Mn x O y @FNS afford plentiful electroactive sites. • This binder-free and defect-rich Mn x O y @FNS needs 105 to attain −10 mA cm−2. • This electrocatalyst exhibits excellent HER stability. [ABSTRACT FROM AUTHOR]

Developing efficient hydrogen evolution reaction (HER) electrocatalysts is extremely important for large-scale hydrogen production from water splitting. In this work, ultra-small MoS 2 nanosheets with 5% Ni doping grown on both sides of hollow carbon microtubes (5%-Ni-MoS 2 /aCMT) are prepared by a hydrothermal method. The vertically oriented Ni-doped MoS 2 nanosheets provide more active sites for HER, while open porous structure promotes ions transport, and hollow carbon microtube substrate accelerates electrons transport as well as hydrogen release. Density functional theory (DFT) analysis proves that the optimal amount of Ni doping can effectively adjust the electronic structure of MoS 2. As a result, 5%-Ni-MoS 2 /aCMT electrode exhibits enhanced kinetics for HER in both acidic and alkaline conditions. To deliver the current density of 10 mA cm−2, it requires overpotentials of 140 and 88 mV in 1 M KOH and 0.5 M H 2 SO 4. 5%-Ni-MoS 2 /aCMT exhibits better stability than commercial Pt/C at a high current density of 200 mA cm−2. Moreover, 5%-Ni-MoS 2 /aCMT/NF (nickel foam) || RuO 2 /NF electrolyzer exhibits ultra-long stability of 30 h at the current density of 100 mA cm−2 and excellent overall water splitting performance with requiring low cell voltages of 1.52 and 1.71 V to generate current densities of 10 and 50 mA cm−2. [Display omitted] • The Ni doping with an optimized content adjusted the electronic structure of MoS 2 , and improved the intrinsic activity. • The ultra-small vertically oriented and defect-rich Ni-doped MoS 2 nanosheets provide more active sites for HER. • The natural N-doped aCMT substrate promotes electron transport during the HER process. • 5%-Ni-MoS 2 /aCMT behaves an enhanced kinetics process based on EIS and DFT analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • The hierarchical Ni-Fe phosphide nanosheets with numerous nanopores were constructed. • The Ni-Fe-P/NF shows superior catalytic activity and durability for both EOR and HER. • Hybrid-water cell exhibits lower energy consumption compared with water electrolysis. • The hybrid water electrolysis product is more valuable than the raw ethanol or O 2. Hydrogen (H 2) generated via water electrolysis exhibits great potential in addressing the urgent environmental and energy issues. Nevertheless, this approach is immensely handicapped by the tardy oxygen evolution reaction (OER). The ethanol oxidation reaction (EOR) can feasibly substitute the OER for hydrogen generation with less power expending on account of the more beneficial thermodynamics and kinetics. Herein, the hierarchical nickel–iron phosphide (Ni-Fe-P) nanosheet directly grown on Ni foam (NF) is proposed as a high-efficiency self-supported bifunctional electrocatalyst. Integrating the advantages of the unique architecture and the composition, the Ni-Fe-P/NF electrode displays highly alluring electrocatalytic activity and stability toward EOR as well as hydrogen evolution reaction (HER). The as-assembled Ni-Fe-P/NF//Ni-Fe-P/NF hybrid ethanol–water electrolyser only requires 1.53 V to supply 10 mA cm−2, outperforming the sole water splitting (1.66 V). Noteworthily, the liquid product of electrolysis is more meritorious than the raw material, highlighting that the hybrid ethanol–water electrolyser we elaborated possesses prodigious potentiality for application in energy-saving H 2 generation and the oxidation of ethanol into acetic acid. This work may provide an innovative strategy in designing and developing other high-efficiency organic molecule electrocatalysts and related energy-saving H 2 production applications in the future. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) derivatives are excellent electrocatalytic materials due to their own structural characteristics. However, it is still very essential to design a logical synthesis route of MOFs derivatives to avoid the adverse effects caused by the collapse of MOFs structure and improve its intrinsic catalytic activity. For these reasons, we designed and synthesized cobalt-based metal-organic framework (ZIF67) grown in situ at the edge of Co(OH) 2 nanosheets. Through adjusting the alcohol-water ratio of the reaction solution, the number of ZIF67 grown on the Co(OH) 2 can be controlled to make it grow uniformly at the edge of nanosheet. After the selenization reaction in a tube furnace, ZIF67 is transformed into CoSe 2 (Co-Z/Se-2) with a yolk-shell structure. This precisely designed synthetic route allows Co-Z/Se-2 to expose more active sites, which is conducive to electron transport and has good performance in both urea oxidation reaction (UOR) and hydrogen evolution reaction (HER). Co-Z/Se-2 as UOR catalyst only needs 1.390 V to reach 50 mA cm−2. Co-Z/Se-2 as bifunctional catalysts, are assembled to be a urea electrolyzer cell. Co-Z/Se-2 || Co-Z/Se-2 only needs 1.490 V to drive 10 mA cm−2, and can maintain a good stability for 20 h. Image 1 • ZIF67 grown on Co(OH) 2 template prevents the stacking phenomenon of ZIF67. • The morphology of ZIF67 can be controlled by the water-alcohol ratio. • CoSe 2 with yolk-shell structure is obtained through selenization reaction. • CoSe 2 as a bifunctional catalyst has an excellent performance in urea electrolysis. [ABSTRACT FROM AUTHOR]

• Ultrathin in-plane 1T-2H MoS 2 heterostructures are coaxially arrayed on 3D CFs. • The 1T-2H ultrathin heterostructures exhibit surprising structure stability. • Our ASC device exhibits an ultrahigh energy density of 81.4 Wh kg−1. Metallic 1T MoS 2 is a promising anode candidate for supercapacitors due to its intrinsically excellent electrical conductivity and high electrochemical activity. However, it is quite unstable and hard to be massively synthesized through common methods. Herein, structurally stable ultrathin (1–3 layers) in-plane 1T-2H MoS 2 heterostructures have been rationally modulated and coaxially aligned on three-dimensional carbon nanofibers (MoS 2 /CF) through a facile hydrothermal approach for supercapacitors and electrocatalysis. Benefiting from the unique heterostructure, the MoS 2 /CF composite shows amazing stability with no obvious change after being stored in air for over 36 months. In addition, it presents high specific capacitance of 310 F g−1 and remarkable rate capability of 78% at 100 mV s−1. The fabricated asymmetric supercapacitor delivers an impressive energy density of 81.4 Wh kg−‍‍‍‍‍1 in 1 M Na 2 SO 4 solution attributed to the high specific capacitance and large operating voltage range of 2 V. Moreover, the MoS 2 /CF composite also demonstrates enhanced electrocatalytic activity for hydrogen evolution reaction with a low overpotential of 194 mV at 10 mA cm−2. The work may promote the developments of high-performance bifunctional energy conversion and storage systems in future. [ABSTRACT FROM AUTHOR]