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Currently, there are still many limitations in the research of conductive metal-organic frameworks (MOFs) in the field of electrocatalysis. On the one hand, most MOFs have a solid construction, seriously hindering their mass transfer process. On the other hand, innate bonding is not conducive to the optimization of electronic structures and the excitation of intrinsic active sites. Therefore, external/internal dual-control of MOFs is urgently needed to break the shackles of their activity. Herein, the hollow RuCoCu-MOF/CF nanorods with tunable cavities are directionally constructed by a self-sacrificial template method. Benefiting from the exact morphological control and the unique Ru–O–Co bond bridge, RuCoCu-MOF/CF exhibits superior performances for alkaline hydrogen evolution reaction (HER) and urea oxidation reaction (UOR). Surprisingly, a record-breaking voltage of 1.402 V drives a current density of 10 mA cm−2 for urea-assisted overall water splitting under alkaline conditions, greatly promoting the development of energy-efficient hydrogen production technology. This work firstly constructed the MOF-based self-supporting electrode with ultra-high urea-assisted hydrogen production and urea degradation performances via the dual controls of the cavity size and chemical bond bridge. This points out the direction for the development of unique integrated electrodes for both hydrogen production and decontamination. "External and internal dual-controls" strategy of the cavity size and chemical bridge construction in RuCoCu-MOF nanorod achieves bifunctional catalysis of urea-assisted energy-saving hydrogen production and urea decomposition. Surprisingly, the unique structure and the formation of the Ru–O–Co bond bridge make RuCoCu-MOF/CF only need a voltage of 1.402 V to reach a current density of 10 mA cm−2 in the energy-efficient HER||UOR electrolyzer, this excellent value represents the highest performance of overall water splitting under alkaline conditions. Besides, RuCoCu-MOF/CF also achieves 2.21 times higher HER activity than commercial Pt/C/CF and splendid UOR properties in the alkaline solution. [Display omitted] • The controllable cavity was constructed by the balance of dissolution-coordination and nucleation-growth processes. • The Ru–O–Co bond bridge as the electron channel optimizes the electronic configuration. • RuCoCu-MOF/CF achieves the record-breaking urea-assisted overall water splitting performance (V 10 = 1.402 V). • RuCoCu-MOF/CF achieves the ultra-low overpotential of 11.6 mV at η 10 for HER, which is better than that of Pt/C/CF. • The ultra-low onset potential of 1.32 V is displayed in RuCoCu-MOF for UOR. [ABSTRACT FROM AUTHOR]

• A capture & ions exchange strategy is used to construct Ru@HMCS/Ru-CoP with rich Ru form. • Ru nanoparticles and Ru dopants synergistically optimize the alkaline HER kinetics. • The unique core–shell structure enhances the conductivity and structural stability. • The η 10 value of Ru@HMCS/Ru-CoP is 2.9 mV, which is 48.8 mV lower than Pt/C. It is challenging to synchronously introduce Ru nanoparticles with strong H* adsorption ability and Ru dopants with excellent electronic regulation to improve hydrogen evolution reaction (HER) performance. With these in mind, this work creatively adopts the capture&ions exchange strategy to construct the Ru@HMCS/Ru-CoP catalyst with the Ru nanoparticles-coated hollow mesoporous carbon spheres (HMCS) shell and the Ru-doped CoP core. Notably, Ru nanoparticles and Ru dopants synergistically promote the optimization of HER kinetics. Moreover, the unique core–shell structure effectively increases the active area, conductivity, and structural stability of Ru@HMCS/Ru-CoP. As expected, the η 10 value of Ru@HMCS/Ru-CoP catalyst (2.9 mV) is 48.8 mV lower than that of Pt/C (51.7 mV). In summary, this work greatly improves the utilization of noble metal atoms and points out the direction for the development of electrocatalysts with low-load noble metal content. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts (SACs) are widely studied in various chemical transformations due to their high catalytic activity and atom utilization. However, modulating the catalytic performance of catalysts by adjusting the microenvironment remains a great challenge. In this paper, a novel master‐double guest vulcanization‐assisted strategy is reported for synthesizing Fe single‐atom catalysts on N,S codoped porous hollow leaf carbon (FeSA/N,S‐PHLC) with highly exposed FeN3SOH sites. Fe(mIm) (guest I) is loaded on the surface of ZIF‐L (host) and then trithiocyanuric acid (TCA, guest II) is bonded with Fe(mIm), and the resulting ZIF‐L@Fe(mIm)@TCA precursors can be converted to FeSA/N,S‐PHLC with controllable structures. In addition, XPS analysis yield an increase in pyridine N content in FeSA/N,S‐PHLC compared to FeSA/N‐PHLC. It can be demonstrated by theoretical calculations that the N,S‐coordinated axially hydroxy‐coordinated asymmetric Fe centers synergistically with the abundance of pyridinic nitrogen facilitate the adsorption and desorption of oxygen intermediates, and the 3d orbitals of the Fe active centers can be optimized. The prepared FeSA/N,S‐PHLC catalyst has a half‐wave potential (E1/2) of 0.91 V under alkaline conditions, and E1/2 = 0.75 V under acidic conditions. It shows excellent cycle stability (882 h) and power density (217 mW cm−2) in the assembly of zinc–air battery (ZABs) devices. [ABSTRACT FROM AUTHOR]

Currently, the construction of heterostructures to optimize electrocatalytic activities is a hot research topic, since there is still a certain gap between the electrocatalytic properties of these heterostructures and that of Pt/C. With this in mind, we utilized in‐situ vapor‐phase phosphorization‐sulfurization to obtain the CoP3/MoS2−Co0.75Mo3S3.75 (CoP/CoMoS, for short) heterostructure on carbon cloth (CC), which exhibits Pt‐like electrocatalytic performance and excellent stability in acid electrolyte. Activated by CoP3 active phase, the electronic configuration of CoMoS and the adsorption energy of H* (▵GH*) are greatly optimized. Meanwhile, the rapid oxidation of CoMoS phase can be effectively avoided under the protection of CoP3 layer. This work provides a reference for the design of heterostructures and their mechanism of action in electrocatalysis. [ABSTRACT FROM AUTHOR]

Transition metal phosphide is regarded as one of the most promising candidates to replace noble‐metal hydrogen evolution reaction (HER) electrocatalysts. Nevertheless, the controllable design and synthesis of transition metal phosphide electrocatalysts with efficient and stable electrochemical performance are still very challenging. Herein, a novel hierarchical HER electrocatalyst consisting of three‐dimensional (3D) coral‐like Mn‐doped Co2P@an intermediate layer of Ni2P generated in situ by phosphorization on Ni foam (MnCoP/NiP/NF) is reported. Notably, both the incorporation of Mn and introduction of the Ni2P interlayer promote Co atoms to carry more electrons, which is beneficial to reduce the force of the Co−H bond and optimize the adsorption energy of hydrogen intermediate (|ΔGH*|), thereby making MnCoP/NiP/NF exhibit outstanding HER performance with onset overpotential and Tafel slope as low as 31.2 mV and 61 mV dec−1, respectively, in 1 m KOH electrolyte. [ABSTRACT FROM AUTHOR]

A heterogeneous structure formed by coupling two or more phases can reinforce the activity of active sites and expedite electron transfer, which is conducive to boosting its electrocatalytic activity. Herein, we designed nickel foam supported (NiCo2)Se@Ni(OH)2 (NCS@NH) heterojunction nanosheets by a two-step method. First of all, the NiCo2S4@Ni(OH)2 (NiCo2S4@NH) nanosheets coated on nickel foam were acquired via a hydrothermal method. In the selenization treatment that followed, NiCo2S4@NH was converted into NCS@NH heterogeneous nanosheets in which the selenide nanoparticles decorated on the surface of the Ni(OH)2 nanosheets formed heterojunction interfaces, and the heterogeneous structure could accelerate electron transfer, thus improving the catalytic activity. The Ni(OH)2 nanosheets can adequately contact the electrolyte and promote the decomposition of water. Meanwhile, the thickness of the Ni(OH)2 nanosheets gradually decreases with the increase of Co doping (1.5–2.5 mmol), consequently affecting the HER properties. Notably, when the amount of Co salt added is 2 mmol, NCS@NH exhibited superior HER properties (with a voltage of 253 mV at 100 mA cm−2) and excellent stability for 24 h. [ABSTRACT FROM AUTHOR]

The investigation and development of bimetallic phosphosulphide electrocatalyst with low cost and abundant reserves is extremely significant for the improvement of the efficiency of hydrogen evolution reaction (HER), while it remains a challenge. Herein, we explored a feasible method to prepare three-dimensional (3D) self-supported FeNiP-S/NF-5 nanosheet arrays on Ni foil (NF) by hydrothermal method and in situ phosphorization and following sulfurization treatment. The as-obtained FeNiP-S/NF-5 only needs a potential of 183 mV vs. RHE to reach 20 mA cm−2, which is smaller than that of FeNiP/NF (187 mV vs. RHE) and FeNiS/NF-5 (239 mV vs. RHE), presenting excellent electrocatalytic stability. Such outstanding performance of the FeNiP-S/NF-5 can be attributed to following several reasons: (i) bi-metallic phosphide and sulphide have the high intrinsic activity because of its synergistic effect; (ii) the 3D nanosheet arrays structure of FeNiP-S/NF-5 is conducive to expose plentiful active sites and facilitate the electrolyte penetration along with electron transportation; (iii) the sulfurization process followed phosphorization treatment could further optimize their electronic structure and inhibited the surface oxidation of catalyst in the catalytic process. Image 1 • NiS modified FeNiP nanosheet electrocatalyst have been synthesized. • The best condition of sulfurization treatment has also been investigated. • The 3D structure and the introduction of NiS can boost activity. [ABSTRACT FROM AUTHOR]

Bimetallic phosphides have been widely investigated as electrocatalysts for oxygen evolution reaction (OER) due to their efficient activity and environmental friendliness. While the reasonable design and controllable synthesis of bimetallic phosphide with typical nanostructure is still a great challenge. Hence, we put forward a novel and straightforward way for constructing FeP nanoparticles coated Ni 2 P ultrathin nanotube arrays on the surface of Ni foil (FeP@Ni 2 P/NF), which is synthesized through two steps of electrodeposition and subsequent in-situ phosphorization process. The obtained FeP@Ni 2 P/NF shows excellent electrochemical activity for OER, and it only needs potential of 1.52 V vs. RHE to reach the current density of 50 mA cm−2 in an alkaline media. The excellent electrocatalytic activity of FeP@Ni 2 P/NF mainly benefits from: (i) the synergistic effect between FeP and Ni 2 P promoting electron transfer; (ii) the formation of the unique 3D ultrathin nanotube arrays increasing the quantity of active sites and avoiding the agglomeration of catalysts during testing. In addition, the influence of reaction condition on the electrochemical activity for OER has also been investigated through altering the phosphorization temperature of precursor. Image 1 • The bimetallic phosphide was obtained through electrodeposition and phosphorization process. • The typical nanoparticle coated nanotube structure could expose more active sites. • Temperature of phosphorization treatment is a crucial factor to the enhanced activity. • The synergistic effective between FeP and Ni 2 P contributes to the excellent performance. [ABSTRACT FROM AUTHOR]

Three compounds constructed by homopiperazine with 1,5-naphthalenedisulfonic acid, 4,5-dichlorophthalic acid and 2,2′,5,5′-biphenyltetracarboxylic acid have been analyzed with respect to hydrogen bonds appeared in the crystal structures. Single crystal X-ray diffraction studies showed that partial protons were transferred to homopiperazine, which made it possible to form N–H⋯O hydrogen bonds in all three compounds. Moreover, O–H⋯O and C–H⋯O hydrogen bonds are founded in 2 and 3 respectively. All of the three compounds displayed 3D supramolecular network structures for the effect of various hydrogen bonds interactions. In addition solvent water molecules and ethanol molecules played an indispensable role in the construction of compounds 2 and 3. Some main supramolecular synthons observed in three compounds were shown to construct most of these hydrogen bonding networks. These new multi-component molecular solids of homopiperazine were characterized by powder X-ray diffraction, infrared spectroscopy, 1H nuclear magnetic resonance and thermogravimetric analysis. Image 1 • Three supramolecular compounds forming by H-bonds were synthesized. • Water molecules play an indispensable role in supporting the structure of 2. • These compounds showed 3D supramolecular network owing to H-bonds interactions. [ABSTRACT FROM AUTHOR]

Transition metal phosphides are very attractive because of the remarkable performance in energy storage and conversion. Herein, a series of bimetallic phosphides are synthesized through a one-step solid-state reaction. The obtained bimetallic phosphides show outstanding properties as supercapacitor electrode materials. Results show that the incorporation of secondary metal into phosphides tunes composition, electronic structure and then the electrochemical performance. And electrochemical properties are closely associated with the secondary metal content. Notably, the obtained NiCoP shows the best performance with 2011 F g−1 at 1 A g−1. And an asymmetric supercapacitor (ASC) based on NiCoP shows energy density of 47.6 W h kg−1, along with 90.5% of capacitance maintained after 10000 cycles. In addition, the NiCoP also possesses great performance toward hydrogen evolution reaction (HER), which displays the lowest potential of 0.221 V vs. RHE and 0.173 V vs. RHE at 10 mA cm−2 in 0.5 M H 2 SO 4 as well as 1.0 M KOH, respectively. The excellent properties may result from the enhanced electrical conductivity, synergistic effects among metal elements and the increased local electrical dipole. The regulation of electronic structure through introduction of secondary metal atom sheds considerable light on realization and preparation of the bimetallic transition metal compounds as electrode materials. • Electronic structure is related to the secondary metal content. • NiCoP shows outstanding performance with 2011 and 1461 F g−1 at 1 and 10 A g−1. • Excellent property is due to increased local electrical dipole and conductivity. • NiCoP holds promise as outstanding electrode material in asymmetric supercapacitor. • NiCoP shows excellent electrocatalytic performance toward HER in both acidic and alkaline solutions. [ABSTRACT FROM AUTHOR]

The introduction of metal atom or heteroatom into transition metal phosphide is an effective strategy to enhance the electrochemical activity for hydrogen evolution reaction, while the controllable synthesis and purposeful design of efficient and stable transition metal phosphide based electrocatalyst with typical structural morphology is still a big challenge. Here, we investigated the relationship among the variety of the doped metal element (Fe and Mn), the corresponding morphology and electrocatalytic performance of the obtained sample for hydrogen evolution reaction. We found that with the doping of Fe and Mn, the cylinder-like CoP has transformed into microflower-like CoP-FeP and rambutan-like CoP-MnP, respectively. Meanwhile, the obtained CoP-FeP exhibits the excellent electrocatalytic activity hydrogen evolution reaction (HER) over a wide pH range (0–14), followed by CoP-MnP and CoP, resulting from the typical nanostructure and the moderately optimized electronic structure of P and Co center. Image 1 • CoP-MP (M = Fe, Mn) nanomaterials with different morphology have been controlled synthesized. • CoP-FeP shows excellent electrochemical performance for HER over a wide pH range (0–14). • The introduction of Fe or Mn element could optimized electronic structure of Co centers and P. [ABSTRACT FROM AUTHOR]

It is a great challenge to induce the formation of the RuP4 phase and realize the construction of a metal‐rich phase/phosphorus‐rich phase‐ruthenium phosphide heterostructure by directional regulation of the proportion of P and metal atoms. The ultra‐high conductivity of Ru2P and the excellent ability of V‐doped RuP4 to absorb/desorb H* are confirmed by density functional theory (DFT) calculations, which laid a theoretical foundation for the construction of a unique Ru2P/V‐RuP4 structure to accelerate HER reaction kinetics. This work innovatively uses the V‐doping strategy to induce the formation of RuP4 phase with high intrinsic activity, and finally construct V‐RuxPy nanosheets with rich Ru/Ru2P/V‐RuP4 heterostructures. Thanks to the rich Ru/Ru2P/V‐RuP4 heterostructure and the optimization of V dopants, the V‐RuxPy catalyst only needs 180 mV to obtain an industrial‐grade current density of 1 A cm−2. In summary, this work provides a new idea for the design and performance optimization of ruthenium‐based catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • a/c-RuCoMo y O x /NF was synthesized by coprecipitation-microwave method. • Microwave time affects the transition from crystalline to amorphous structure. • a/c-interface and electron interaction make a/c-RuCoMo y O x /NF have mighty activity. • The η 10 value of a/c-RuCoMo y O x /NF is 39 and 166 mV for HER and OER. Due to the vast difference in structure and the unique electronic state at the heterointerface, the amorphous/crystalline (a/c) heterostructure exhibits excellent potential in electrocatalysis. However, there are great challenges in constructing the material with ample a/c-heterointerfaces and controllably modulated a/c-heterointerface region through a simple one-step method. Herein, the a/c-RuCoMo y O x /NF (nickel foam) electrocatalyst is synthesized by the coprecipitation-microwave treatment method. Notably, microwave time directly affects the ratio of amorphous region (RuCoMoO x) to crystalline region (CoMoO 4 and CoO). Surprisingly, the a/c-RuCoMo y O x /NF with abundant crystallinity/amorphous heterointerfaces exhibits the ultralow η 10 values of 39 and 166 mV for HER and OER, which are 0.5-fold and 0.63-fold lower than that of Pt/C-NF and RuO 2 -NF benchmarks, respectively. Overall, this work provides a novel idea and convenient method for the construction of amorphous/crystalline heterointerfaces with modulated interface region, and guides the direction for the preparation of superior electrocatalysts by regulating the a/c-heterointerface region. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The uniform bimetallic CoFeP hollow microspheres have been synthesized. • The hollow structure of CoFeP is helpful to increase the exposed actives. • The bimetallic composites can provide the better intrinsic activity. • The synergistic effect from bimetallic phosphides contributes to the enhanced performances. Abstract The ingenious design and synthesis of bifunctional electrocatalysts with high activity and robust stability for hydrogen evolution reaction and oxygen evolution reaction (HER and OER) is desirable and challenging. Herein, bimetallic phosphides CoFeP with hollow microspheres structure has been synthesized through a facile gas phosphorization as bifunctional electrocatalyst for overall water splitting. SEM and TEM demonstrate the formation of uniform hollow microspheres of CoFeP. The hollow structure of CoFeP is helpful to increase the exposed actives and the larger contact surface with electrolyte. The bimetallic composites can provide the better intrinsic activity. Compared with single metallic phosphides CoP and FeP, the obvious enhancement of electrocatalytic performances of CoFeP can be observed. The electrochemical results show that the bimetallic CoFeP hollow microspheres only have the lower overpotential of 177 and 350 mV (vs. RHE) to drive a current density of 10 mA cm−2 for HER and OER, respectively. The reasons may be due to the hollow nanostructure and the synergistic effect from bimetallic phosphides. This work provides a facile and effective way to design excellent phosphides electrocatalysts for water splitting based on gas phosphorization of bimetallic oxides precursors. [ABSTRACT FROM AUTHOR]

Abstract Stable, earth-abundant and efficient electrocatalysts for overall water splitting are urgently needed. In this work, we have reported the synthesis of FeNiP/NC hollow microboxes (FeNiP/NC) based bifunctional electrocatalyst via the phosphorization process using rationally designed cube-type metal-organic framework (FeNi-MOF) as both the template and carbon source. The FeNiP/NC, which were obtained by assembling the uniform FeNiP nanoparticals together through N-doped carbon, manifests outstanding catalytic performances for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in KOH solution. Notably, FeNiP/NC displays exceptional activity when it was utilized as both anode and cathode toward overall water splitting with potential of 1.54 V at a current density of 10 mA cm−2 in alkaline electrolyte, which is much better than FeP/NC and Ni 2 P/NC electrocatalyst. More importantly, the improvement of the catalytic activities of FeNiP/NC mainly benefits from the well dispersion of FeNiP nanoparticles on the surface of carbon support, the large active surface area and the doping of N and C derived from organic ligands. In addition, the enhanced electrocatalytic performance of FeNiP/NC for OER is closely related with the in-situ formed surficial MOOH (M = Fe, Ni) active sites, which has been confirmed by X-ray photoelectron spectroscopy (XPS) analysis. Graphical abstract Image 1 Highlights • Uniform FeNiP nanoparticles assembled together through N-doped carbon based hollow microboxs have been synthesized. • FeNiP/NC was obtained using FeNi-MOF as precursor. • Hollow FeNiP/NC is a bifunctional electrocatalyst for HER and OER in alkaline media. • The MOOH (M = Fe, Ni) with high activity for OER have in-situ formed on the surface of FeNiP/NC. [ABSTRACT FROM AUTHOR]

Abstract The suitable hydrogen-binding free energy (ΔG H*) of active sites for hydrogen evolution reaction (HER) is the key for enhancing the electrocatalytic performances of transition metal based electrocatalysts. Usually metal/nonmetal elemental doping and unique nanostructure can be used to adjust the M H bonding energy for accelerating both generation and departure of H 2. Herein, a simple in-situ phosphorsulfurization method has been used to synthesized nickel cobalt phosphosulphide (NiCoP|S/CC) nanoneedles grown on the surface of carbon cloth (CC) at low temperature as electrocatalyst for hydrogen evolution reaction (HER) in both acid (0.5 M H 2 SO 4) and alkaline (1.0 M KOH) electrolyte solution. Typically, NiCo 2 O 4 /CC with nanoneedles structure is used as precursor. And NaH 2 PO 2 and H 2 S is used as phosphorus and sulfur source, respectively. Compared with single metal phosphophides, the enhanced electrocatalytic performance of NiCoP|S/CC for HER can be attributed to the formation of new specie phosphosulphide and synergistic effect between phosphosulphide and carbon support CC. This work provide a new method with adjusting ΔG H* of active sites for preparing the excellent electrocatalysts for water splitting. Graphical abstract Image 1 Highlights • NiCo 2 O 4 /CC with nanoneedles was used as precursor for the phosphosulphide. • The phosphosulphide can provide the suitable ΔG H* for hydrogen evolution. • The synergistic effect between phosphosulphide and carbon support contributes to the enhanced activity. [ABSTRACT FROM AUTHOR]

It is impending but still a big challenge to design and synthesize electrocatalyst with typical nanostructure and efficient catalytic activity for hydrogen evolution reaction (HER). Herein, we report a low-temperature phosphorization process to synthesize nickel-iron bimetallic phosphides (NiFeP) using MIL-88-Fe 2 Ni MOF (metal-organic framework) as precursor. The as-synthesized NiFeP shows superior electrocatalytic performance with lower onset overpotential, smaller Tafel slope, bigger exchange current density and lower overpotential to reach the current density of 10 mA cm −2 than both NiP 2 and FeP for HER in alkaline solution. The enhanced electrochemical activity may be attributed to the existence of the synergistic effect between NiP 2 and FeP. SEM and TEM images show that the obtained NiFeP bimetallic phosphides preserve the size and morphology of the parent MIL-88-Fe 2 Ni MOF. And the prominent and stable performance of NiFeP nanorods for HER may also ascribes to the typical rod-like nanostructure with large specific surface area. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS 2) exhibits the modest properties toward hydrogen evolution due to its poor electrical conductivity and a limited number of active sites. To make up for the defects in MoS 2 , we built hierarchical P-doped MoS 2 /NiS 2 @carbon hollow nanospheres (P–MoS/NiS@CHNS) electrocatalyst via one-step hydrothermal method owning to the priority of the reaction between Ni2+ and H 2 S. Motivated by high-efficient electron transfer at the interface of heterostructure and the activation of MoS 2 by P dopant, P–MoS/NiS@CHNS exhibits optimal Gibbs free energies (ΔG H∗) and superior HER performance with low overpotential (ƞ 10) of 110 ​mV ​at 10 ​mA ​cm−2 and small Tafel slope of 61 ​mV dec−1. The focus of this work is to optimize the HER performance of MoS 2 through P-doping and heterostructure construction, which can further provide a reference for the design of MoS 2 based catalysts. Image 1 • The P–MoS 2 /NiS 2 heterostructure is in favor of expeditious electrons transfer. • Thanks to the priority of the reaction between Ni2+ and H 2 S, the heterostructure was constructed. • The introduction of P optimizes the electron configuration of MoS 2. • The well-designed P–MoS/NiS@CHNS electrocatalyst has the optimal ΔG H∗ and E a value. [ABSTRACT FROM AUTHOR]

Transition metal nitrides (TMNs) have attracted great attention as ideal active materials in the field of electrocatalysts in recent years due to their excellent electrical conductivity, wide band gap and adjustable morphology. Pure phase Co 4 N nanoparticles encapsulated nitrogen-doped carbon (NC) nanotubes (Co 4 N@NC) were in-situ synthesized by one-pot method. In this paper, the morphology of carbon nanotubes is controlled by adjusting the pyrolysis time, so that more active sites are exposed on carbon nanotubes. Thus, the cobalt nitride catalyst with excellent catalytic performance for hydrogen evolution reaction (HER) in acidic electrolyte was obtained. In summary, due to the protection of mesoporous nitrogen-doped carbon to Co 4 N nanoparticles, large electrochemically active surface area, good conductivity and more exposed active sites, Co 4 N@NC possesses excellent HER performance in acidic electrolytes. The overpotential of Co 4 N@NC at the current density of 10 mA cm−2 is 117 mV (η 10), and it shows long-term stability in 0.5 M H 2 SO 4 solution for 50 h. This study provides a strategy for the development of catalysts for the controllable synthesis of high-performance transition metal nitrides. [Display omitted] [ABSTRACT FROM AUTHOR]

Co and N co-doped RuO 2 nanosheets with rich V O (N,Co-RuO 2 -V O) were constructed by the 'melting-quenching' method. Thanks to the synergistic optimization of the electronic configuration of Ru and the reaction path of the basic HER by V O and N dopants, N,Co-RuO 2 -V O exhibited an impressive HER activity of 2208.63 mA m g R u - 1 mass activity at 100 mV, which was 8.05-fold that of Pt/C (274.2 mA m g P t - 1 ). [Display omitted] • Co,N-RuO 2 nanosheets with rich O defects were prepared by melting-quenching. • V O and N dopants synergistically optimized the electronic structure of Ru atoms. • The Ru-N dual active sites mechanism accelerates alkaline HER. • The mass activity of N,Co-RuO 2 -V O was 8.05-fold that of Pt/C due to the of N and V O. • N,Co-RuO 2 -V O obtained an industrial current density of 1 A cm−2 at only 148.6 mV. Optimizing the electronic structure of Ru by introducing N dopants or O vacancies (V O) into RuO 2 is expected to be a promising strategy to stimulate the hydrogen evolution reaction (HER) performance. However, it is a challenge to develop a fast and low-energy method to simultaneously achieve the construction of N dopants and V O. This work was the first to optimize the quenching technique for achieving the co-introduction of V O and N in Co-RuO 2 nanosheets (N,Co-RuO 2 -V O). Related characterizations confirmed that V O and N dopants synergistically optimized the electronic configuration of Ru and the reaction path of alkaline HER. As expected, the mass activity of N,Co-RuO 2 -V O (2208.63 mA m g R u - 1 ) was 8.05-fold that of Pt/C at 100 mV for alkaline HER. Surprisingly, N,Co-RuO 2 -V O required only 148.6 mV to achieve an industrial-grade current density of 1 A cm−2, which was much lower than the commercial Pt/C catalyst (312 mV). Overall, this work provides an energy-efficient new strategy for the development of Ru-based catalysts with ampere-level currents. [ABSTRACT FROM AUTHOR]

In this work, nickel cobalt bimetallic sulfide with typical multi-shell hollow sphere structure behaved superior electrocatalytic activity towards hydrogen evolution reaction (HER), which have been prepared through a easy method included solvothermal step, calcination step and in-situ sulfurization step. The composition and structure of the obtained nickel cobalt bimetallic sulfide are controlled through adjusting the sulfurization temperature and dosage of sulfur source. The as-prepared Ni–Co-S multi-shell hollow microspheres (abbreviated as Ni-Co-S) behaves superb HER properties in alkaline medium and Ni-Co-S-340(60) performs the most superior property, in which reflected the lowest overpotential (129 mV vs. RHE) at the current density of 10 mA cm−2 and the smallest Tafel slope (96.1 mV dec−1) among all the synthesized samples. The superior electrocatalytic performance of the obtained Ni-Co-S-340(60) for HER is owing to the unique multi-shell hollow structure derived from the intrinsic porous character of Ni-Co-BTC MOF precursor in one hand. And in the other hand, introducing highly active NiCo 2 S 4 into NiS 2 would enhance its elctrocatalytic activity because of the strong interfacial effect between NiS 2 and NiCo 2 S 4. Image 1 [ABSTRACT FROM AUTHOR]

In this work, we synthesized Se doped MoS 2 @Ni 3 S 2 with nanosheets coated nanorods structure supported on Ni foam (MoNiSeS). Firstly, MoS 2 @Ni 3 S 2 (MoNiS) nanorods was synthesized by hydrothermal method. After selenization treatment, MoSe 2 successfully formed on the edge of MoS 2 nanosheets and particle Ni 3 S 2 transformed into NiSe, in which MoSe 2 and NiSe acted as new phase in MoNiSeS. The obtained MoNiSeS only needs a low overpotential of 68 mV to reach the current density of 10 mA cm−2, and has a low Tafel plots of 72.77 mV dec−1 and good electrochemical durability, whose electrochemical activity is much better than that of MoNiS and NiSeS, implying the introduction of Mo and Se is beneficial to improve the electrocatalytic performance of NiS for HER. In addition, the proper amount of Mo source, which has an effect on the morphology of product, has also been investigated. For MoNiSeS, the typical nanosheets coated nanarods expose more active sites and the synergic effects is good to the improvement of the catalytic activity. Meanwhile, WNiSeS has also been prepared using the same method and the corresponding results show that the electrochemical activity of WNiSeS is much better than that of NiSeS, proving the universality of this strategy. • The introduction of Mo and Se can improve the activity of NiS for HER. • The effect of the Mo on the morphology of product has been investigated. • MoNiSeS with nanosheets coated nanorods structure have been synthesized. [ABSTRACT FROM AUTHOR]

Rational construction of high‐efficiency and low‐cost catalysts is one of the most promising ways to produce hydrogen but remains a huge challenge. Herein, interface engineering and heteroatom doping were used to synthesize V‐doped sulfide/phosphide heterostructures on nickel foam (V‐Ni3S2/NixPy/NF) by phosphating treatment at low temperature. The incorporation of V can adjust the electronic structure of Ni3S2, expose more active sites, and protect the 3D structure of Ni foam from damage. Meanwhile, the heterogeneous interface formed between Ni3S2 and NixPy can provide abundant active sites and accelerate electron transfer. As a result, the V‐Ni3S2/NixPy/NF nanosheet catalyst exhibits outstanding activity in the hydrogen evolution reaction (HER) with an extremely low overpotential of 90 mV at a current density of 10 mA cm−2 and stable durability in alkaline solution, which exceeds those most of the previously reported Ni‐based materials. This work shows that rational design by interfacial engineering and metal‐atom incorporation has a significant influence for efficient hydrogen evolution. [ABSTRACT FROM AUTHOR]

Developing efficient, stable and ideal urea oxide (UOR) electrocatalyst is key to produce green hydrogen in an economical way. Herein, Ru doped three dimensional (3D) porous Ni 3 N spheres, with tannic acid (TA) and urea as the carbon and nitrogen resources, is synthesized via hydrothermal and low-temperature treated process (Ru–Ni 3 N@NC). The porous nanostructure of Ni 3 N and the nickel foam provide abundant active sites and channel during catalytic process. Moreover, Ru doping and rich defects favor to boost the reaction kinetics by optimizing the adsorption/desorption or dissociation of intermediates and reactants. The above advantages enable Ru–Ni 3 N@NC to have good bifunctional catalytic performance in alkaline media. Only 43 and 270 mV overpotentials are required for hydrogen evolution (HER) and oxygen evolution (OER) reactions to drive a current of 10 mA cm−2. Moreover, it also showed good electrocatalytic performance in neutral and alkaline seawater electrolytes for HER with 134 mV to drive 10 mA cm−2 and 83 mV to drive 100 mA cm−2, respectively. Remarkably, the as-designed Ru–Ni 3 N@NC also owns extraordinary catalytic activity and stability toward UOR. Moreover, using the synthesized Ru–Ni 3 N@NC nanomaterial as the anode and cathode of urea assisted water decomposition, a small potential of 1.41 V was required to reach 10 mA cm−2. It can also be powered by sustainable energy sources such as wind, solar and thermal energies. In order to make better use of the earth's abundant resources, this work provides a new way to develop multi-functional green electrocatalysts. [Display omitted] • The synthesized electrocatalyst exhibits porous specific sphere morphology to exposed abundant active sites. • The prepared electrocatalyst presents excellent electrocatalytic performances toward HER, OER and UOR. • Small overpotential is required to drive overall water-splitting under the urea assistance with remarkable stability. • Sustainable energies are investigated to power the electrolyzer for hydrogen generation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Introducing Co and P to activate inert Cu-based nanowires to achieve efficient HER/OER. • Co-doped Cu 3 P nanospheres stacked into nanochains by through a valid approach. • Prepared catalyst has excellent HER/OER activity and long term stability. Developing durable, effective and inexpensive electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are crucial for the advancement of water splitting as a solution to the energy shortage. In this study, nanospheres stacked into nanochains are successfully prepared by oxidative corrosive engineering, solvothermal, and following calcination process (Co-Cu 3 P/CF). The unique nanochain structure facilitates growing the specific surface area, thereby exposing plenitude active sites. The introduced phosphorus (P) and Co ions can alter the electronic characteristics of metal phosphides, not only can accelerate the electron transport of the catalysts, but speed up the reaction kinetics. Thus, the prepared Co-Cu 3 P/CF exhibits low overpotentials, with 240/84 mV, in alkaline media for OER/HER to attain 10 mA cm−2. In alkaline freshwater/seawater, the self-assembled electrolyzer needs only 1.51/1.58 V to achieve 10 mA cm−2. This work provides an approach for the preparation of high-performing and economical electrocatalysts. [ABSTRACT FROM AUTHOR]

Using low cost and high efficiency non-precious bimetallic phosphosulphide as electrocatalyst for hydrogen evolution reaction (HER) is not only convenient but also environment-friendly for industrial production. Therefore, we propose a simple and efficient method to prepare a series of Cu-doped bimetallic phosphosulphide nanosheet arrays on nickel foam (CuNiS@Ni 2 P/NF). The CuNiS@Ni 2 P/NF exhibits the superior HER performance with appropriate doping amount of Cu. It just needs a potential of 144 mV to obtain the current density of 10 mA cm−2 in 1.0 M KOH, which is smaller than that of CuNiS@Ni 2 P/NF-0.25 (206 mV) and CuNiS@Ni 2 P/NF-0.125 (219 mV). The excellent HER performance of CuNiS@Ni 2 P/NF nanosheet arrays can be ascribed to: (i) the moderate Cu-doped effectively optimized the electronic structure and morphology of the electrocatalyst; (ii) typical nanosheet arrays structures exposing more active sites; (iii) the high immanent activity excited by the multi-component synergy. • Cu-doped bimetallic phosphosulphide nanosheet arrays on Ni foam has been prepared. • The moderate amount of Cu doping could optimize the electronic structure of the product. • The typical structure and multi-component synergy contribute to the enhanced performance. [ABSTRACT FROM AUTHOR]

• The RuP 4 @CoP/Ti electrocatalyst with acacia-like structure was obtained using a facile method. • The incorporation of Ru can accelerate the charge transfer between Ru, Co, and P. • The RuP 4 @CoP/Ti possesses super activity under either acidic or alkaline solution. • The existence of Ti foil could enhance the electrical conductivity and disperse the active phases. The transition metal phosphate with lower price and rich abundance have a tendency to replace Pt-based catalytic materials for hydrogen evolution reaction (HER). Nevertheless, for transition metal phosphate based electrocatalyst, the further improvement of the electrocatalytic performance and the deep exploration of the regulation and control mechanism are still bottleneck problems. At present, we use a novel method to prepare the Ti foil supported the CoP acacia-like arrays decorated with RuP 4 nanoparticles composite (RuP 4 @CoP/Ti). The obtained RuP 4 @CoP/Ti possesses excellent electrocatalytic performance, which needs the overpotential of 66.2 mV to reach the current of density of 10 mA cm−2 and has the Tafel slope of 52.6 mV dec−1 in 0.5 M H 2 SO 4. In addition, it requires the overpotential of 36 mV to reach the current of density of 10 mA cm−2 and has Tafel slope of 54.8 mV dec−1 in 1 M KOH. Moreover, the obtained RuP 4 @CoP/Ti also presents outstanding long-term durability under either acidic or alkaline condition. The reason for such excellent properties is due to the unique acacia-like structure, the synergistic effect between CoP and RuP 4 , the existence of Ti foil and the introduction of Ru, which can optimize the electronic structure of Co and P. [ABSTRACT FROM AUTHOR]

• NiCo-LDH decorated NiCoS nanorods with hierarchical structure has been prepared. • The moderate amount of NiCo-LDH by electrodeposition could enhance the activity. • The synergistic effect of the composite contribute to the enhanced performance. As the key step in the overall water splitting system, hydrogen evolution reaction (HER) has become one of the main methods of hydrogen production in industrial applications. Here, through the strong coupling between NiCo-LDH nanosheets and NiCoS nanorods, the three-dimensional heterogeneous structure formed by the composite can provide a large catalytic specific surface area. The modification of LDH lamellar will provide abundant edge active sites and enhance its structural stability. The synergistic effect of NiCo-LDH and NiCoS can optimize the electronic structure and promote mass transfer and water cracking. Benefiting from the above points, the NiCoS@NiCo-LDH/NF obtained showed the significant boost in HER process. It only required 99 mV to reach current density of 10 mA·cm−2 and maintained excellent durability for 24 h for HER, which proved NiCoS@NiCo-LDH/NF was a cost-free, high-efficient and outstandingly stable HER catalyst in basic solution. [ABSTRACT FROM AUTHOR]

The development of phosphide-based electrocatalyst with excellent properties and good stability under both acidic and alkaline condition is the hotspot of recent research. Herein, we synthesized N doped CoP coated with carbon nanotubes (CoP@NC) electrocatalyst for hydrogen evolution reaction (HER), in which, the ZIF-67 (ZIF = zeolite imidazole skeleton) nanoparticles wrapped Co-MOF (MOF = metal-organic skeleton) nanorods has been used as precursor. The improvement of catalytic performance of N-doped CoP can be attributed to the fact that the introduction of N can optimize the electronic structure and the in-situ grown carbon nanotubes can improve charge transfer rate and avoid the agglomeration of active units. In addition, the effect of phosphorization temperature and the amount of carbon nanotube on the electrochemical activity of the samples were also investigated, and the obtained CoP@NCs only required low overpotential of 250 mV and 234 mV to drive the current density of 100 mA cm−2 under acidic and basic conditions, respectively. This work opens up an efficient paradigm for optimizing the performance of electrocatalysts. • N doped CoP coated with carbon nanotubes (CoP@NC) has been synthesized. • The in-situ formed carbon nanotubes could efficiently improve the charge transfer rate. • The use of Co-MOF in the core part could efficiently the accumulation of active phase. • The carbonization atmosphere has an obviously effect on the electrocatalytic performance. [ABSTRACT FROM AUTHOR]