Efficient Electrocatalytic Water Splitting Research Articles

Double MOF gradually activated S bond induced S defect rich MILN-based Co(z)-NiMoS for efficient electrocatalytic overall water splitting.

Herein, cactus like nanorods with rich S defects and functional group MILN-based Co(z)-NiMoS are synthesized through a facile method. First, we prepared MIL-88B precursor to give a fairly dispersed frame structure, and then Con+ was doped into disulfides, which are rich in sulfur bonds, and the imidazole group was cleverly connected into graphitized carbon via self-etching of ZIF-67. The doping of Con+ and functional groups makes tiny changes in the sulfide lattice, which promotes the unsaturation degree of the S bond and activates it gradually. The prepared semi frame sulfide with a unique structure, on the one hand, ensures the hydrophilicity and multiple active specific surface area, which lays superior functions in morphology. On the other hand, coupling metals that have strong valence change ability and functional groups by active S bonds play an important role in the process of electrocatalytic reaction. Amazingly, disintegration and self-reconstruction of MILN-based Co(z)-NiMoS occurs during oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) due to the activation of the S bond, which provides a new perspective for the overall water splitting mechanism. The electrochemical results show that the MILN-based Co(z)-NiMoS electrocatalyst exhibits overpotentials of HER, OER, and overall water splitting (OWS) to be 169 mV, 170 mV, and 1.466 V, respectively, making it a promising electrode material for OWS applications.

Nickel selenide from single-molecule electrodeposition for efficient electrocatalytic overall water splitting

The prepared electrode (NiSe-TMEDA/CC) from single-molecule electrodeposition is functional for both the OER and HER and shows a superior performance for overall water splitting with a low cell voltage in alkaline medium.

Engineering multinary heterointerfaces in two-dimensional cobalt molybdenum phosphide hybrid nanosheets for efficient electrocatalytic water splitting

A Co–Mo–P NS with rich heterointerfaces was elaborately constructed by a facile successive phosphidation strategy. The multinary heterointerfaces can optimize the ΔGH* and the reaction kinetics, thus contributing to the enhanced catalytic activity.

Ar plasma-assisted P-doped Ni3S2 with S vacancies for efficient electrocatalytic water splitting.

Doping engineering is considered an effective way to improve the electrocatalytic water splitting performance of catalysts. In this paper, P-doped Ni3S2/NF was prepared by Ar plasma-assisted chemical vapor deposition, where the P dopant was efficiently introduced into Ni3S2/NF under the assistance of Ar plasma. Meanwhile, numerous vacancies were generated due to plasma bombardment. In the doping process, the P dopants replace the S vacancies, which contributes to the strong bonding between the P dopants and Ni3S2. Due to the synergistic effect of the P dopants and S vacancies, the Sv-Ni3S2-xPx-4 catalyst has low HER and OER overpotentials of 89 mV and 216 mV at 10 mA cm-2, with a lower impedance value and good stability. The present work shows a facile route to introduce dopants and vacancies into catalyst materials for adding active sites, eventually improving their electrocatalytic performance.

Fe–Co–P multi-heterostructure arrays for efficient electrocatalytic water splitting

The local electronic structure can be adjusted by constructing the Fe–Co–P multi-heterostructure catalyst, leading to improved adsorption of the reaction intermediate on the active site and outstanding HER/OER and overall water splitting performances.

Ultrathin 2D flower-like CoP@C with the active (211) facet for efficient electrocatalytic water splitting

Due to the more exposed (211) facet, the electrocatalytic water splitting activity of 2D CoP@C is superior to that of its counterpart 3D structure.

Controllable synthesis of one-dimensional NiS2 nanotube and nanorod arrays on nickel foams for efficient electrocatalytic water splitting

One-dimensional NiS2 nanotube arrays and nanorod arrays are controllably grown on Ni foam surface. The electrocatalytic test shows that the NiS2 nanotube arrays require competitive overpotentials of 209 mV for HER and 367 mV for OER (to achieve a current density of 50 mA/cm2), respectively, which are much lower than the NiS2 nanorod arrays and other NiS2 nanostructures reported before. Specifically, the NiS2 nanotube arrays can be employed as an efficient bi-functional catalyst for overall water splitting, with a low cell voltage (1.58 V) to deliver a current density of 10 mA/cm2. The outstanding performance can be attributed to the special structural characteristics of nanotubes, which have high specific surface areas along with abundant active sites. The present study not only enriches the morphology of NiS2 nanostructures for highly efficient electrocatalytic reaction, but also provides an interesting self-assembly path for the synthesis of one-dimensional NiS2 nanostructures.

Synergistically modulating electronic structure of NiS2 hierarchical architectures by phosphorus doping and sulfur-vacancies defect engineering enables efficient electrocatalytic water splitting

• P-doped NiS 2 hierarchical architectures with sulfur vacancies are synthesized. • The amounts of P dopants and sulfur vacancies could be precisely controlled. • The optimal catalyst manifests excellent catalytic performance with duriability. • The P dopant activates the electrochemical activities of neighboring Ni and S sites. • The association of P doping with S vacancies tunes the d-band center position. The synergistic achievement of heteroatom doping, defect engineering and appropriate structural design is efficient to adjust and boost the catalytic performance of catalysts yet challenging. Herein, phosphorus (P)-doped NiS 2 hierarchical architectures with sulfur vacancies are synthesized via a Prussian-blue-analogue-sacrificed strategy followed by a phosphidation process. By modulation of P doping and sulfur vacancies, the optimal catalyst manifests outstanding electrocatalytic activities, affording low overpotentials of 73 mV at 10 mA cm −2 for hydrogen evolution reaction (HER), and 255 mV at 20 mA cm −2 for oxygen evolution reaction (OER), respectively. Density functional theory calculations certify that the P dopant not only serves as the new active sites, but also activates the electrochemical activity of neighboring Ni and S sites. Moreover, the synergistic effect of P-doping and sulfur vacancies further improve electrochemical activities of HER and OER by optimizing the adsorption free energy of hydrogen (ΔG H* ) and oxygen-containing intermediates (OH*, O* and OOH*), respectively. This finding provides a directive strategy to achieve efficient non-noble metal catalysts for energy conversion and storage.

Modification strategies on transition metal-based electrocatalysts for efficient water splitting

Electrocatalytic water splitting driven by electrocatalysts is recognized as a promising strategy to generate clean hydrogen fuel. Searching and constructing high-efficient and low-cost electrocatalysts is vital in the practical applications of electrocatalytic water splitting. Although transition metal-based materials have been considered as promising electrocatalysts, the satisfactory activities are usually not built on the bulk materials, but strongly relying on elaborately designing these electrocatalysts. Herein, the recent theoretical and experimental progress on modification strategies to improve the intrinsic activities is summarized, especially including element doping, phase engineering, structure cooperation, interface engineering, vacancy engineering, strain engineering and self-functionalization. Finally, the future opportunities and challenges on these modification strategies are also proposed. Overall, it is anticipated that these modification strategies offer some new understandings on rationally constructing non-noble electrocatalysts for efficient electrocatalytic water splitting.

Decorating CoNi layered double hydroxides nanosheet arrays with fullerene quantum dot anchored on Ni foam for efficient electrocatalytic water splitting and urea electrolysis

The design and construction of noble-metal-free electrocatalysts with superior activity, high efficiency and robust stability is still a big challenge for overall water and urea splitting. Herein, a novel hybrid electrocatalyst comprising fullerene quantum dot (FQD)-decorated CoNi layered double hydroxides (CoNi-LDH) nanosheet arrays anchored on porous Ni foam (NF) is elaborately fabricated. Beneficial from the synergetic effect between FQD and CoNi-LDH, the obtained FQD/CoNi-LDH/NF exhibits superior electrocatalytic activity for hydrogen and oxygen evolution as well as urea oxidation under ambient atmosphere. Impressively, to drive a current density of 10 mA cm−2, it requires cell voltages of only 1.59 and 1.45 V for overall water and urea electrolysis, respectively, in a two-electrode electrolyzer consisting of FQD/CoNi-LDH/NF as both anode and cathode. Furthermore, this catalyst also displays outstanding reaction kinetics and favorable catalytic stability. Both experimental and density functional theory (DFT) calculation results demonstrate that the charge transfer from FQD to CoNi-LDH could account for the excellent catalytic performance of the newly-synthesized catalyst, and the decorated FQD finely modulates the electronic structure of CoNi-LDH, favoring the adsorption of active hydrogen atom, and thus promote the catalytic process. The present work would provide useful guidance for designing and developing multifunctional and efficient electrocatalysts for hydrogen production.

Designed synthesis of hierarchical Mn3O4@SnO2/Co3O4 core-shell nanocomposite for efficient electrocatalytic water splitting

The hierarchical Mn3O4@SnO2/Co3O4 core-shell nanocomposite has been successfully synthesized via a facile structural construction strategy. The SnO2/Co3O4 nanosheets (SnO2/Co3O4 NSs) were enclosed on the surface of Mn3O4 nanorods (Mn3O4 NRs). The prepared materials were investigated as the catalyst toward oxygen evolution reaction (OER) performance in alkaline. By contrast, the design of core-shell hierarchical nanocomposite of Mn3O4@SnO2/Co3O4 possesses the obvious electrocatalytic OER performance than others, showing the overpotential of approximately 420 mV at a current density of 10 mA cm−2 with a low Tafel slope of 70.1 mV dec−1, in which the interesting structure can provide the interfacial and cooperative effect between core (hierarchical SnO2/Co3O4 NSs) and shell (1D Mn3O4 NRs) that 1D Mn3O4 NRs can act as an electron acceptor and accelerates electron transfer, and that hierarchical SnO2/Co3O4 NSs provide a large specific surface area and multiple exposed surface active sites between electrode material and electrolyte.

Nanoporous NiAl-LDH nanosheet arrays with optimized Ni active sites for efficient electrocatalytic alkaline water splitting

A novel nanoporous NiAl-LDH nanosheet array with optimized Ni active sites is prepared for efficient electrocatalytic alkaline water splitting.

Constructing NiS–VS heterostructured nanosheets for efficient overall water splitting

Self-supported porous NiS/VS heterostructured nanosheets were designed towards efficient electrocatalytic water splitting.

Synthesis of an iron-doped 3D-ordered mesoporous cobalt phosphide material toward efficient electrocatalytic overall water splitting

The development of porous metal phosphides with abundant active sites is of great importance for efficient electrocatalytic water splitting.

Boosting hydrogen and oxygen evolution reactions on electrodeposited nickel electrodes via simultaneous mesoporosity, magnetohydrodynamics and high gradient magnetic force

Efficient electrocatalytic water splitting (HER and OER) using electrodeposited mesoporous nickel electrodes, significantly improved by the magneto-hydrodynamic effect and high-gradient magnetic force, is demonstrated.

Hierarchical 2D yarn-ball like metal–organic framework NiFe(dobpdc) as bifunctional electrocatalyst for efficient overall electrocatalytic water splitting

MOF electrocatalyst, NiFe(dobpdc) (dobpdc = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate), has a 2D nanosheets structure with large pore size, high surface area and exhibits electrocatalytic activity for OER and HER with extremely low overpotentials.

Co-Doped FeS2 with a porous structure for efficient electrocatalytic overall water splitting

The development of earth-abundant and high-efficiency electrocatalysts for overall water splitting is highly fascinating and still presents a challenge caused by the low activity for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) at the same time.

Rational design of Cu–Co thiospinel ternary sheet arrays for highly efficient electrocatalytic water splitting

CuCo2S4 ternary sheet arrays are successfully synthesized on the micro-fibre of carbon felt, which exhibits excellent OER, HER and overall water splitting performance benefiting from the unique structure.

Construction of hierarchical nickel/cobalt iron-hydroxide and nickel/cobalt selenide nanotubes for efficient electrocatalytic water splitting

Hierarchical Ni/CoFeOH and Ni/CoSe2 nanotube arrays were fabricated via a three-step strategy, and exhibited enhanced electrochemical performance for OER and HER, respectively.

Sandwich-like structured NiSe2/Ni2P@FeP interface nanosheets with rich defects for efficient electrocatalytic water splitting

Constructing well-defined nanointerfaces is vital to enhance the catalytic performances through electronic coupling effects from different components. However, it is still a challenge to construct metal selenides-based interfacial nanomaterials with satisfactory oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performances for overall water splitting. Herein, sandwich-like structured NiSe2/Ni2P@FeP nanosheet arrays are rationally constructed, which starts from NiSe2 arrays directly on carbon cloth as backbones, followed by coating FeP nanoparticles on the backbones through the phosphorization process. Further, abundant nanointerfaces with rich defects and disordered structure are constructed during the phosphorization process, which can boost the charge transfer rate and provide rich electroactive sites. Consequently, as-synthesized NiSe2/Ni2P@FeP nanosheet arrays exhibit good HER and OER performances with small overpotentials, low Tafel slopes and good stability. Further, the overall water splitting device built by NiSe2/Ni2P@FeP exhibits a voltage of 1.554 V to attain 10 mA cm−2. Our current work may provide some new insights on rationally constructing nanointerfaces with rich defects to boost the catalytic performances for overall water splitting.