NiMoO4 Nanorods Research Articles

A core-shell structured catalyst for enhanced oxygen evolution: NiFe double hydroxide coating over phosphorus -modified NiMoO4 nanorod cores

In this paper, we innovatively employed low-temperature phosphorization technology to successfully incorporate P doping into NiMoO4 nanorods. Subsequently, utilizing the electrodeposition method with a solution rich in Ni²⁺ and Fe³⁺ as the electrolyte, we delicately tuned the process to identify the optimal deposition time, achieving a uniform coating of NiFe LDH on the surface of the P-doped NiMoO4 nanorods. This led to the construction of a three-dimensional core-shell structured NiFe LDH@P-NiMoO4 composite material. To validate the performance of this composite, we conducted thorough structural characterization and electrochemical oxygen evolution reaction (OER) performance tests. The experimental results revealed that in a 1 M KOH electrolyte environment, when the current density reached 100 mA cm⁻², the composite exhibited exceptionally superior OER performance, with an overpotential of merely 267 mV and a Tafel slope as low as 93 mV dec⁻¹, firmly demonstrating its remarkable catalytic efficiency. Furthermore, the composite displayed good stability and durability during prolonged testing, providing a solid foundation for its practical application. In summary, this work not only paves a new way for the preparation of high-performance non-precious metal OER electrocatalysts but also provides robust support for the realization of efficient and stable energy conversion and storage technologies.

MXene introduced between CoNi LDH and NiMoO4 nanorods arrays: A bifunctional multistage composite for OER catalyst and supercapacitors

To improve the electrochemical activity and electrochemical energy storage performance of the catalyst, one of the best approaches is to adjust materials structure reasonably and design of micro-array to enhance specific surface area and expose more active sites. In this work, CoNi-LDH/MXene@NiMoO4 electrode with multistage structure was successfully designed, in which CoNi-LDH was vertically arranged on NiMoO4 nanorods coated with MXene. Oxygen evolution reaction (OER) performance was improved through the adjustment of LDH by MXene. The electrode has an excellent OER activity, which the overpotential is 222 mV at 100 mA cm−2. In addition, it can maintain high efficiency and stable operation for 120 h. The overall water-splitting (OWS) electrolytic cell was assembled with CoNi-LDH/MXene@NiMoO4 electrodes, which exhibited a low cell voltage (1.56 V) at 10 mA cm−2. Moreover, the assembled OWS electrolytic cell can operate stably under the low voltage by small-scale solar power generation and thermal power generation. Furthermore, CoNi-LDH/MXene@NiMoO4 electrode also showed good potential in electrochemical energy storage. This work opened a new avenue for MXene to regulate the activity of transition metal-based catalysts. The efficient preparation of clean energy by the interaction of MXene and transition metal groups show great prospects.

Microplasma-assisted construction of cross-linked network hierarchical structure of NiMoO4 nanorods @NiCo-LDH nanosheets for electrochemical sensing of non-enzymatic H2O2 in food

The accumulation of small doses of hydrogen peroxide (H2O2) into food can cause many diseases in the human body, and it is urgent to develop efficient detection methods of H2O2. Herein, the hierarchical structure composite of NiCo-LDH nanosheets crosslinked NiMoO4 nanorods was grown in situ on carbon cloth (NiMoO4 NRs@NiCo-LDH NSs/CC) by micro-plasma assisted hydrothermal method. Thanks to the synergistic effect of three metals and (NiMoO4 NRs@NiCo-LDH NSs/CC) provided by nanorods/nanosheets hierarchical structure, NiMoO4 NRs@NiCo-LDH NSs/CC exposes more active sites and achieves rapid electron transfer. The H2O2 electrochemical sensor was constructed as the working electrode with a linear range of 1 μmol L−1 to 9.0 mmol L−1 and detection limit of 112 nmol L−1. In addition, the sensor has been successfully applied to the detection of H2O2 in food samples, the recovery rate is 95.2%–106.62%, RSD < 4.89%.

Mesoporous NiMoO4 nanorod electrode materials for flexible and asymmetric energy storage devices.

Recently, ternary metal oxides as cathode materials have been the focus of research into supercapacitors owing to their high power density and cost-efficient features. The development of excellent electrode materials is the key to improving supercapacitor total performance. Herein, we report several kinds of NiMoO4 nanostructures grown on nickel foam using a simple hydrothermal strategy. The assembled hybrid devices show an energy density of 35.9 W h kg-1 at a power density of 2708 W kg-1. After repeated charging and discharging cycling and bending tests, they show excellent durability performance and mechanical stability performance.

In situ growth of NiMoO4-C nanocomposite and electrodeposition of multi-metal selenide to enhance oxygen evolution efficiency in alkaline solution

This study primarily centers on the fabrication of NiMoO4-C@Ni(FeMo)-Se composite electrocatalysts directly onto nickel foam substrates through a hydrothermal followed by electrodeposition technique. Through this method, the carbon submicron sphere structure, interlinked by NiMoO4 nanorods, undergoes further optimization, resulting in a more refined NiMoO4-C@Ni(FeMo)-Se core-shell structure. The NiMoO4-C@ Ni(FeMo)-Se /NF composite electrode exhibited exceptional OER catalytic activity in a 1 M KOH solution, with an overpotential of merely 228 mV at a current density of 50 mA·cm−2 and a Tafel slope of 35.9 mV·dec−1, significantly superior to that of the blank NF. Additionally, a 40-hour stability test at a current density of 50 mA·cm−2 demonstrated that the potential remained nearly constant, highlighting the exceptional OER activity and long-term stability of the synthesized catalyst. Moreover, in the overall water splitting process, the utilization of a dual-electrode NiMoO4‐C@Ni(FeMo)‐Se/NF||Pt‐C/NF electrolytic cell demands a remarkably low potential of 1.48 V to achieve a current density of 10 mA·cm−2, demonstrating exceptional electrocatalytic activity and long-term stability. Therefore, this study provides a promising route for the application of hydrogen production from alkaline aqueous solutions.

Synthesis of Ni decorated MoOx nanorod catalysts for efficient overall urea-water splitting.

Substituting slow oxygen evolution reaction (OER) with thermodynamically favorable urea oxidation reaction (UOR) is considered as one of the feasible strategies for achieving energy-saving hydrogen production. Herein, a uniform layer of NiMoO4 nanorods was grown on nickel foam by a hydrothermal method. Then, a series of Ni-MoOx/NF-X nanorod catalysts comprising Ni/NiO and MoOx (MoO2/MoO3) were prepared through regulating annealing atmosphere and reduction temperature. The optimized Ni-MoOx/NF-3 with a large accessible specific area can act as a bifunctional catalyst for electrocatalytic anodic UOR and cathodic hydrogen evolution reaction (HER). At a current density of 100 mA cm-2, the introduction of urea can significantly reduce the overpotential of Ni-MoOx/NF-3 by 210 mV compared to OER. In addition, Ni-MoOx/NF-3 has a higher intrinsic activity than other catalysts. It only requires -0.21 and 1.38V to reach 100 mA cm-2 in HER and UOR, respectively. Such an excellent performance can be attributed to the synergistic function between Ni and MoOx. The presence of metallic Ni and reduced MoOx in pairs is beneficial for improving the electrical conductivity and modulating the electronic structure, resulting in enhancing the electrocatalytic performance. When assembling Ni-MoOx/NF-3 into an overall urea-water splitting system, it can achieve energy-saving hydrogen production and effective removal of urea-rich wastewater.

Tuning d–p Orbital Hybridization of NiMoO4@Mo15Se19/NiSe2 Core‐Shell Nanomaterials via Asymmetric Coordination Interaction Enables the Water Oxidation Process

AbstractThe electrocatalytic performance of MoNi‐based nanomaterials undergo selenization has garnered significant interest due to their modified electronic structure, while still posses certain challenges for obtained bimetallic selenides. Here, a novel MoNi‐based electrocatalyst of NiMoO4@Mo15Se19/NiSe2 core‐shell nanomaterials is constructed to promote the desorption of OOH* which can facilitate the water oxidation process. NiMoO4@Mo15Se19/NiSe2 core‐shell nanoarrays show that the “cores” are mainly NiMoO4 nanorods while the “shells” are the bimetallic selenides nanoflakes, which are super architectures that can expand more active sites and accelerate the electron transfer. Moreover, the hybridization interaction between Ni 3d, Mo 4d, and Se 4p orbitals leads to an asymmetric distribution of electric clouds, which decreases the adsorption energy and transformation of oxygen‐containing species. Electrochemical data displays that the overpotentials of NiMoO4@Mo15Se19/NiSe2 core‐shell nanomaterials are only 195 mV, 220 mV, and 224 mV for oxygen evolution reaction (OER) in alkaline freshwater, alkaline simulated seawater, and alkaline natural seawater. The current density decay is negligible after 100 h stability at about 1.46 V with a three‐electrode system in alkaline natural seawater. The low cost and the unique MoNi‐based bimetallic selenides in this work provide a more constructive solution for designing efficient and stable OER catalysts in the future.

Fe/P dual-doping NiMoO4 with hollow structure for efficient hydrazine oxidation-assisted hydrogen generation in alkaline seawater

Electrosynthesis of hydrogen straightforwardly from seawater represents a potential solution towards carbon-neutral economy. However, with the sluggish oxygen evolution reaction (OER) at anode, the sustainable and cost-effective application is greatly hindered by extra energy consumption and serious chlorine chemistry in seawater. Herein, based on the advanced hydrazine-assisted electrolysis strategy, we reported a trifunctional Fe, P dual-doping NiMoO4 nanorods with a hollow structure for highly active hydrogen evolution reaction (HER) (23 mV @ 10 mA cm−2) and OER (213 mV @ 10 mA cm−2) activity, which also significantly decreased the cell voltage (activity variation for ∼1.40 V) in two-electrode system by replacing OER with thermodynamically beneficial hydrazine oxidation reaction (HzOR). Notably, a record low electricity expense of 2.3 kW h m−3 was obtained among commercial reactor in alkaline seawater/0.5 M N2H4. Meanwhile, the corrosion resistance of catalyst allows stable catalytic performance in seawater without any ClO- generation. Density functional theory calculations showed that Fe/P co-doping effectively endowed optimized electronic structure and modulated d-band centre for intermediates adsorption/desorption.

A highly efficient and long-term durable electrocatalyst for oxygen evolution in alkaline seawater by growing Ni1.5Fe1.5B on the NiMoO4 nanorods

The development of efficient and stable catalysts for the oxygen evolution reaction (OER) that can function effectively in seawater is crucial for addressing the energy crisis. In this study, a low-cost hydrothermal-dip-coating method was employed to synthesize Ni1.5Fe1.5B nanosheets decorated three-dimensional NiMoO4 nanorods anchored on nickel foam (NiMoO4@Ni1.5Fe1.5B). This catalyst exhibits high conductivity and electrochemically active surface areas, which can be attributed to the synergistic effect between NiMoO4 and Ni1.5Fe1.5B, the presence of numerous oxygen vacancies, and the modification of boron. The NiMoO4@Ni1.5Fe1.5B catalyst exhibits exceptional catalytic activity for the oxygen evolution reaction (OER), as evidenced by overpotentials of 235 and 262 mV required to achieve current densities of 100 and 200 mA cm−2, respectively, in 1 M KOH. Notably, the leaching of Mo during the OER in alkaline conditions contributes to the preservation of the 3D core-shell structure of NiMoO4@Ni1.5Fe1.5B, resulting in improved stability and resistance to chloride-induced corrosion. In seawater with a concentration of 1 M KOH, the catalyst requires overpotentials of 261 and 299 mV to achieve current densities of 100 and 200 mA cm−2, respectively, and can operate continuously for 72 h without significant performance degradation.

Atomic ruthenium doping in collaboration with oxygen vacancy engineering boosts the hydrogen evolution reaction by optimizing H absorption

Development of cost effective and performance efficient catalyst for hydrogen evolution reaction (HER) holds great importance to advance a green future. In this work, atomic Ru doped NiMoO4 nanorod arrays with rich oxygen vacancy were tailor-synthesized on nickel foam. Both theoretical calculations and experiments elucidated the synergistic effects of Ru doping and oxygen vacancy engineering for the facilitating of H adsorption and water activation energy barrier reduction for water dissociation, which significantly enhanced the hydrogen evolution kinetics and thereby accelerated the water splitting process. The sample obtained exhibits a remarkably low overpotential of 49 mV at 10 mA cm−2 and a super robust stability, which is comparable to the performance of commercially available Pt/C and among one of the most efficient catalysts towards water splitting. Moreover, an integrated green energy-to-hydrogen device using sunlight, wind and thermal as the power sources was successfully built to prove the promising potential of the developed catalyst for the practical applications. This work provides a feasible strategy to prepare low-cost metal oxide electrocatalysts by noble element doping and oxygen vacancy engineering for efficient hydrogen evolution reaction.

Ni2P/Co2P as a highly efficient catalyst for enhancing the electrochemical performance of P-NiMoO4 for oxygen evolution reaction

A growing trend in electrocatalysis is to explore interfacial interactions and surface intermediate adsorption in highly efficient bimetallic phosphide catalysts for developing efficient oxygen evolution reactions (OER). In this work, Ni2P and Co2P nanoparticles (NPs) were distributed on P-modified NiMoO4 nanorods prepared by the hydrothermal procedure, which exhibited high catalytic activity and outstanding durability for the OER. By regulating the high interfacial contact between Ni2P, Co2P, and P-NiMoO4, the Ni2P and Co2P NPs reduced the electron density, thus optimizing the OER. Compared to the NiMoO4 NRs, the P-NiMoO4@Ni2P/Co2P electrocatalyst showed remarkable activity towards the OER owing to the strong electron interaction and synergistic effect among the three components. Consequently, the P-NiMoO4@Ni2P/Co2P electrode yielded significant OER activity, with an overpotential of 260 mV, a Tafel slope of 41 mV/dec, and 92.9% Faradaic efficiency. Furthermore, the P-NiMoO4@Ni2P/Co2P electrocatalyst demonstrated excellent stability (up to 50 h) for the OER, which was higher than those of the NiMoO4-based catalysts reported in the literature. Several factors contribute to the excellent OER activity, including electron transfer between Ni2P, Co2P, and P-NiMoO4, and the abundant active sites generated from their interfacial interactions. Therefore, this study presents a novel approach for developing highly efficient ternary electrocatalysts for the long-term electrocatalytic evolution of oxygen.

Clever fusion of structure and function: A coupled sulfurization-driven OER performance study based on ZIF-67 nanoparticles and NiMoO4 nanorods

Hydrogen fuel cells (HFCs) and water electrolysis are emerging clean energy technologies that can alleviate the problems of environmental pollution and energy shortage. Oxygen Extraction Reaction (OER) is a slow four-electron transfer process with a high energy barrier, and often regarded as the bottleneck of a series of clean energy technologies. In this paper, NiMoO4 nanorods (denoted as NMO) were in situ grown on nickel foam substrate, and then ZIF-67 nanoparticles were assembled onto NiMoO4 nanorods (denoted as NMO@ZIF-67). Finally, the surface layers of NiMoO4 nanorods and ZIF-67 nanoparticles were vulcanized by hydrothermal treatment for 6 h to obtain the catalyst NiMoO4 @NiMoCo-S-6 (denoted as NMO@NMC-S-6). In 1 M KOH aqueous solution, NMO@NMC-S-6 exhibited excellent electrochemical performance, only 176 mV and 243 mV overpotentials were required at current densities of 10 and 100 mA cm-2, respectively, and Tafel slope of NMO@NMC-S-6 is 24.81 mV dec-1. In addition, benefitting from the combined structure of nanorods and nanoparticles effectively prevented nanoparticles aggregation and enhanced its own structure and transport channel stability, NMO@NMC-S-6 showed remarkable stability in 20 h electrochemical test. This work brings a reference orientation for constructing cost-efficient alkaline OER catalyst through structure combination strategy.

Heterogeneous bimetallic oxides/phosphides nanorod with upshifted d band center for efficient overall water splitting

Electrocatalytic water splitting is the most directly available route to generate renewable and sustainable hydrogen. Here, we report the design of a composite material in which arrays of square pillar-like NiMoO4 nanorods coated with N, P-doped carbon layers are uniformly contained in numerous nested nanoparticle structures. The catalysts have superior catalytic activity, requiring only 59 mV and 187 mV for HER and OER to attain a current density of 10 mA/cm2, respectively. The assembled two-electrode electrolytic cell required a voltage of 1.48 V to reach 10 mA/cm2, along with excellent long-term stability. Theoretical calculations reveal that electrons aggregate and redistribute at the heterogeneous interface, with the d-band centers of the Ni and Fe atoms being positively shifted compared to the Fermi level, effectively optimizing the adsorption of intermediates and reducing the Gibbs free energy, thus accelerating the catalytic process. Meanwhile, an integrated solar-driven water-splitting system demonstrated a high and stable solar-to-hydrogen efficiency of 18.20%. This work provides new possibilities for developing non-precious metal-based bifunctional electrocatalysts for large-scale water splitting applications.

Boosting the Catalytic Performance of NiMoO4 Nanorods in H2 Generation upon NH3BH3 Hydrolysis via a Reduction Process.

Although a range of noble metal catalysts, including Ru, Rh, Pd, Pt, and Au, have been developed for efficient H2 generation upon NH3BH3 hydrolysis at room temperature, this is a highly urgent need for exploring earth-abundant metal nanocatalysts for H2 generation upon NH3BH3 hydrolysis. Herein, a NaBH4 reduction strategy was developed to boost the catalytic performance of NiMoO4 nanorods in H2 generation upon NH3BH3 hydrolysis. Indeed, the pristine NiMoO4 nanorods were catalytically inert in NH3BH3 hydrolysis. Significantly, the reduced NiMoO4 nanorods presented excellent catalytic activity in H2 generation upon NH3BH3 hydrolysis, with a turnover frequency (TOF) of 31.2 L(H2)·gcat-1·h-1. Interestingly, the TOF of NH3BH3 hydrolysis over reduced NiMoO4 nanorods significantly increased from 31.2 to 53.6 L(H2)·gcat-1·h-1 under 0.3 M NaOH. The boosting catalytic performance of NiMoO4 nanorods via NaBH4 reduction in H2 generation might be attributed to the higher content of Oads and the formation of nickel boride in the reduced NiMoO4 nanorods. In this work, NH3BH3 hydrolysis over reduced NiMoO4 nanorods was not only used for safe H2 generation but also for its in situ tandem hydrogenation in organic chemistry.

Sugar gourd-like NiCo layered double hydroxide @ NiMoO4 hierarchical core-shell material for high-performance asymmetric supercapacitors

As one of the strategies for preparing electrode materials with excellent electrochemical properties, reasonable structural design has been widely used to improve the performance of electrode materials. In this work, a core-shell structure with a unique sugar gourd-like appearance is designed, in which NiMoO4 (NMO) nanorods string together multiple NiCo-LDH (NCL) hollow nanocages to form NCL@NMO/NF composite electrode. The unique structure and the synergistic effect between the two substances give it high cycle stability and excellent capacity. DFT calculations show that the electronic structure at the NCL@NMO heterogeneous interface changes after compounding, so that electrons are transferred from the NCL to the NMO surface, and the difference in the work function promotes the transfer of electrons and accelerates the reaction rate. When used as the positive electrode of asymmetric supercapacitor (ASC), the material exhibits a specific capacity of 1186 C g−1 at a current density of 1 A g−1, and a capacity retention rate of 85.5 % after 5000 cycles at 5 A g−1. In addition, the assembled NCL@NMO/NF//AC ASC exhibits a high energy density of 80.38 Wh kg−1 at a power density of 800 W kg−1, and has high cycle stability (89.2 % after 5000 cycles).

A high-performance NiMoO4/g-C3N4 direct Z-scheme heterojunction photocatalyst for the degradation of organic pollutants

Photocatalytic degradation of harmful organic pollutants in water has been considered an important research subject due to its efficient and cost–effective handling of toxic substances for ecosystems protection. We report a direct Z–scheme heterojunction photocatalyst made up of NiMoO4/g–C3N4 (NMOCN) nanocomposite for degrading the antibiotic, i.e., ciprofloxacin (CIP) and the organic dye, i.e., malachite green (MG). The nanocomposites were systematically prepared, and their structural, morphological, optical, and photoelectrochemical properties were analyzed. XRD analysis verified that NiMoO4 had a monoclinic crystal structure. The FESEM and HRTEM images showed that NMOCN composites were comprised of NiMoO4 nanorods coupled with g-C3N4 nanosheets. UV−VIS absorbance spectral analyses showed that NMOCN composites had a narrow band gap with good visible light absorption properties. Mott–Schottky and EIS measurements revealed that NMOCN composites had an optimum band structure and low charge transfer resistance for heterojunction formation. Increasing the relative mass content of g–C3N4 in NMOCN composites improved the photocatalytic degradation efficiency. NMOCN–30 (30 wt.% of g–C3N4) composite provided a maximum degradation efficiency, i.e., 90.82% for CIP (in 75 min) and 98.84% for MG (in 120 min), while showing excellent stability against CIP and MG up to six consecutive cycles. In addition, the EPR measurement and trap test results proved that all ·OH, ·O2–, and h+ participated in photodegradation activity. Thus, the presented nanocomposite photocatalysts with a Z–scheme heterojunction can help to build up a viable strategy for water pollution treatment with enhanced photocatalytic degradation capabilities.

NiMoO4@H–BiMoNi with nanorod cluster structure for an efficient hydrogen evolution reactions in electrocatalysts

The physicochemical and electrocatalytic properties of existing single-component electrocatalyst for the hydrogen evolution reaction can hardly meet the requirements for widespread industrial applications, so the development of more efficient and mature electrocatalyst for the hydrogen evolution reaction is necessary. In this study, the growth of BiMoNi nanorod clusters on nickel foam (NF/NiMoO4) modified with nickel molybdate was investigated using a direct electrocatalyst for the hydrogen evolution reaction. Vertically aligned NiMoO4 nanorods act as the central growth framework providing a large number of electrochemical sites and fast ion electron transfer channels. BiMoNi nanocluster particles were used to modify the NiMoO4 nanorods, where the in situ growth of Bi–O bonds promoted an increase in charge transfer, further improving the efficiency of the response of material to electrochemical hydrogen evolution reactions. The final NF/NiMoO4@H–BiMoNi nanorod cluster achieved the best electrocatalytic performance, with the NF/NiMoO4@H–BiMoNi nanorod cluster structure exhibiting a low overpotential of 53 mA at a current density of 10 mA cm−2 in a 1.0 M KOH solution. The results indicate that the electrocatalyst for the hydrogen evolution reaction studied in this thesis have some potential applications.

Construction of Ni4Mo/MoO2 heterostructure on oxygen vacancy enriched NiMoO4 nanorods as an efficient bifunctional electrocatalyst for overall water splitting

Despite great efforts over the past decade, rational design of bifunctional electrocatalysts with low cost and high efficiency still remains a challenge to achieve industrial water splitting. Herein, we synthesized the nickel-molybdenum nanorod array catalyst supported on NF (NMO@NM/MO) by a two-step process of hydrothermal and reductive annealing. Partial reduction of the NiMoO4 induces the structural reconstruction and formation of the Ni4Mo/MoO2 heterostructure on oxygen vacancy enriched nanorod, which bring out sufficient active sites, large specific surface area and favorable interfacial charge transfer. Thanks to the unique core–shell structure with the heterostructured Ni4Mo/MoO2 surface and defect-rich NiMoO4 core, the obtained electrocatalyst shows greatly improved hydrogen evolution reaction (HER) activity with an ultralow overpotential of 63 mV at 100 mA cm−2 (vs. 314 mV for the NiMoO4). Density function theory calculations reveal that the construction of the Ni4Mo/MoO2 heterostructure effectively accelerates H2O dissociation kinetics, while the defective NiMoO4 facilitates H* adsorption/desorption. Moreover, the heterostructure catalyst also displays excellent oxygen evolution reaction (OER) performance with the low overpotential of 274 mV at 100 mA cm−2. When coupling HER and OER by using NMO@NM/MO as both the cathode and anode, the alkaline electrolyzer delivers a current density of 10 mA cm−2 at only 1.50 V as well as good robustness. The synergistic effect of the hetero-interface and the defect engineering endows the electrocatalyst with excellent bifunctional catalytic activity for HER and OER. This work may provide a route for rational design of heterostructure electrocatalysts with multiple active components.

Flower-like CoP coated NiMoO4 nanorods as self-supported core-shell heterojunction electrode can facilitate oxygen evolution reaction at a low overpotential

Transition metal phosphates, as the most promising catalyst for oxygen evolution reaction (OER), have attracted much attention in recent years. In this work, CoP nanosheets are electrodeposited on NiMoO4 nanorods to form a self-supported core-shell structure electrode with CoP-NiMoO4 heterojunctions. Density functional theory (DFT) calculations demonstrate CoP-12@NiMoO4/NF electrode can reduce reaction energy barrier of rate-determining step (RDS) from 8.743 eV to 2.519 eV. In 1 M KOH, the electrode shows a low overpotential of 165 mV (10 mA cm−2), a low Tafel slope of 45 mV dec−1 and the significant stability. Compared with other non-noble metal OER electrocatalysts, the prepared CoP-12@NiMoO4/NF electrode exhibits better electrocatalytic activity, which can provide a new choice of electrocatalysts for future practical applications.

NiMoO4/Eu6MoO12 composite on foam Ni as electrode material for supercapacitors

By a one-step hydrothermal reaction, NiMoO4/Eu6MoO12 composite supported on nickel foam was successfully synthesized. The properties of the composite were optimized by adjusting the content of europium nitrate in the reactants. The NiMoO4 nanorods array formed on nickel foam was used as structural support, and Eu6MoO12 nanoparticles were added to the surface, increasing the material's specific surface area and the active site.The two chemicals' combined effect made the electrode reaction more reversible. In addition, Eu with variable oxidation states increased the oxygen vacancy and promoted the Faraday reaction. And the formation of Eu6MoO12 also significantly reduced the charge transfer resistance of the composite, it influenced the electrochemical behavior of materials. Electrochemical experiments show that the specific capacity of NiMoO4/Eu6MoO12 is 1184.0 C g−1 at 1 A/g. The energy density of NiMoO4/Eu6MoO12//AC device is 22.34 W h kg−1 when the power density is 749.52 W kg−1. In addition, the device also has a capacity retention rate of 80.2% after 5000 cycles. The material's superior electrochemical performance demonstrates that it has promising future applications in the realm of energy storage.