Herein, ruthenium (Ru) and iridium (Ir) are introduced to tailor the atomic and electronic structure of self-supported nickel-vanadium (NiV) layered double hydroxide to accelerate water splitting ...kinetics, and the origin of high hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities are analyzed at atomic level. X-ray photoelectron spectroscopy and X-ray absorption near-edge structure spectroscopy studies reveal synergistic electronic interactions among Ni, V, and Ru (Ir) cations. Raman spectra and Fourier and wavelet transform analyses of the extended X-ray absorption fine structure indicate modulated local coordination environments around the Ni and V cations, and the existence of V vacancies. The Debye-Waller factor suggests a severely distorted octahedral V environment caused by the incorporation of Ru and Ir. Theoretical calculations further confirm that Ru or Ir doping could optimize the adsorption energy of intermediates in the Volmer and Heyrovsky steps for HER and accelerate the whole kinetic process for OER.
A closely interconnected network of MoP nanoparticles (MoP‐CA2) with rich nanopores, large specific surface area, and high conductivity can function as a highly active non‐noble metal catalyst for ...electrochemically generating hydrogen from acidic water. The network exhibits nearly 100% Faradaic efficiency and needs overpotentials of 125 and 200 mV to attain current densities of 10 and 100 mA cm−2, respectively. The catalytic activity is maintained for at least 24 h.
Water electrolysis is considered as the most promising technology for hydrogen production. Much research has been devoted to developing efficient electrocatalysts for hydrogen production via the ...hydrogen evolution reaction (HER) and oxygen production via the oxygen evolution reaction (OER). The optimum electrocatalysts can drive down the energy costs needed for water splitting via lowering the overpotential. A number of cobalt (Co)‐based materials have been developed over past years as non‐noble‐metal heterogeneous electrocatalysts for HER and OER. Recent progress in this field is summarized here, especially highlighting several important bifunctional catalysts. Various approaches to improve or optimize the electrocatalysts are introduced. Finally, the current existing challenges and the future working directions for enhancing the performance of Co‐implicated electrocatalysts are proposed.
Electrochemical water splitting is a well‐established technology with which to produce high‐purity hydrogen. Recent progress in cobalt‐based heterogeneous electrocatalysts for water splitting is reviewed. Strategies to obtain optimized or enhanced performance are introduced through specific examples. The current existing challenges and future working directions for enhancing the performance of Co‐implicated electrocatalysts are discussed.
The development of cost-effective hydrogen evolution reaction (HER) electrocatalysts based on 3d-transition metal is highly desired but still challenging. Herein, we report on the synthesis of the ...three-dimensional self-supported nickel-oxide-coated cobalt manganese sulfide nanosheets array on carbon cloth (CoMn-S@NiO/CC), which is used as an efficient electrocatalyst for HER in alkaline media. The performance of CoMn-S@NiO/CC is significantly improved through an in situ electrochemical reduction process. The electrochemically activated CoMn-S@NiO/CC (ECA CoMn-S@NiO/CC) drives 100 and 200 mA cm–2 at overpotentials of 232 and 278 mV, respectively, with long-term stability for hydrogen production in 1.0 M KOH. Such high hydrogen evolution activity for ECA CoMn-S@NiO/CC is owed to the incorporation of Co ions, increase in electrochemically active surface area, and the newly formation of amorphous regions on its surface.
In this communication, we demonstrate for the first time that ultrathin graphitic carbon nitride (g-C₃N₄) nanosheets can serve as a low-cost, green, and highly efficient electrocatalyst toward the ...reduction of hydrogen peroxide. We further demonstrate its application for electrochemical glucose biosensing in both buffer solution and human serum medium with a detection limit of 11 μM and 45 μM, respectively.
The development of low-cost, high-efficiency, and stable bifunctional electrocatalysts toward the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is of paramount importance for ...large-scale water splitting. Here, we develop a new strategy for the first design and synthesis of a NiO@Ni decorated WS2 nanosheet array on carbon cloth (NiO@Ni/WS2/CC) composite. This composite serves as a unique three-dimensional (3D) synergistic electrocatalyst that not only combines the intrinsic properties of individual NiO@Ni and WS2, but also exhibits significantly improved HER and OER activities when compared to that of pure NiO@Ni and WS2. This electrocatalyst possesses Pt-like activity for HER and exhibits better OER performance than that for commercial RuO2, as well as demonstrating superior long-term durability in alkaline media. Furthermore, it enables an alkaline electrolyzer with a current density of 10 mA cm–2 at a cell voltage as 1.42 V, which is the lowest one among all reported values to date. The excellent performance is mainly attributed to the unique 3D configuration and multicomponent synergies among NiO, Ni, and WS2. Our findings provide a new idea to design advanced bifunctional catalysts for water splitting.
In this Letter, we demonstrate the direct growth of FeP nanoparticles film on carbon cloth (FeP/CC) through low-temperature phosphidation of its Fe3O4/CC precursor. Remarkably, when used as an ...integrated 3D hydrogen evolution cathode, this FeP/CC electrode exhibits ultrahigh catalytic activity comparable to commercial Pt/C and good stability in acidic media. This electrode also performs well in neutral solutions. This work offers us the most cost-effective and active 3D cathode toward electrochemical water splitting for large-scale hydrogen fuel production.
In this communication, cobalt phosphide nanoparticles film was developed on carbon cloth (CoP NPs/CC) through low-temperature phosphidation of its corresponding Co NPs/CC precursor. When directly ...used as a cathode for electrochemical hydrogen evolution in strongly acidic solutions, the CoP NPs/CC electrode exhibits high performance with a low onset overpotential of 33 mV, a Tafel slope of 70 mV dec−1 and a Faradaic efficiency of nearly 100%. This catalyst maintain its catalytic activity for at least 30 h and only needs overpotentials of 48 and 190 mV to attain current densities of 10 and 100 mA cm−2, respectively.
•CoP nanoparticles film on carbon cloth (CoP NPs/CC) was derived from Co NPs/CC.•CoP NPs/CC acts as an acid-stable hydrogen evolution cathode with superior activity.•CoP NPs/CC exhibits long-term electrochemical stability.
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•Ni-WN heterostructure nanowires array on carbon cloth (Ni-WN/CC) was firstly fabricated.•This Ni-WN/CC was directly used as a 3D hydrogen-evolving cathode.•This electrode exhibits ...superior catalytic activity.
Earth-abundant Ni has emerged as an interesting catalytic material toward electrochemical hydrogen evolution reaction (HER) in alkaline media, but developing high-performance Ni-integrated HER catalysts is still a big challenge. Herein, we describe the development of self-standing Ni-tungsten nitride heterostructure nanowires array on conductive carbon cloth (Ni-WN/CC) as a highly efficient 3D hydrogen-evolving cathode in 1.0M KOH with catalytic activity outperforming most reported Pt-free HER catalysts. This Ni-WN/CC electrode exhibits a negligible onset overpotential and a Tafel slope of 71mVdec−1. It demands overpotentials of only 47, 70, and 155mV to drive 10, 20, and 100mAcm−2, respectively, with its activity being maintained for 10h. Such high hydrogen evolution activities are due to electrocatalytic synergistic effects of Ni and WN.
In this communication, for the first time, we demonstrate the electrodeposition of Ni3S2 on ZnO (ZnOatNi3S2) array supported on nickel foam. We further demonstrate the direct use of ZnOatNi3S2 array ...as a binder-free electrode material for supercapacitors and this electrode exhibits a very high specific capacitance of 1529 F ga1 at a current density of 2 A ga1, good rate capability and cycling stability.
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