High-efficiency Hydrogen Evolution Reaction Research Articles

Interfacial engineering of CoP-MoO2/NF heterojunction for high-efficient hydrogen evolution reaction coupled with 5-hydroxymethylfuran electrooxidation

Achieving efficient production of hydrogen and obtaining high value-added products can maximize energy efficiency, but challenging. Herein, a nanoarray-structured heterojunction catalyst (CoP-MoO2/NF) was proposed as a potent bifunctional electrocatalyst for hydrogen evolution reaction (HER) and 5-hydroxymethylfuran oxidation reaction (HMFOR). Density Functional Theory (DFT) showed that heterojunction enhanced the adsorption of reactants on the electrocatalyst surface, the CoP-MoO2/NF exhibits excellent HER activity with an overpotential of 37 mV and a Tafel slope of 43 mV·dec−1 at 10 mA·cm−2. Also, nearly 100% HMF conversion and 98.6% FDCA selectivity demonstrate the favorable performance of the material toward HMFOR. The work here shows a way for producing hydrogen in the future that is low-cost, efficient, reliable and also adds value to the final product.

Intercalated PtCo Electrocatalyst of Vanadium Metal Oxide Increases Charge Density to Facilitate Hydrogen Evolution.

Efforts to develop high-performance electrocatalysts for the hydrogen evolution reaction (HER) are of utmost importance in ensuring sustainable hydrogen production. The controllable fabrication of inexpensive, durable, and high-efficient HER catalysts still remains a great challenge. Herein, we introduce a universal strategy aiming to achieve rapid synthesis of highly active hydrogen evolution catalysts using a controllable hydrogen insertion method and solvothermal process. Hydrogen vanadium bronze HxV2O5 was obtained through controlling the ethanol reaction rate in the oxidization process of hydrogen peroxide. Subsequently, the intermetallic PtCoVO supported on two-dimensional graphitic carbon nitride (g-C3N4) nanosheets was prepared by a solvothermal method at the oil/water interface. In terms of HER performance, PtCoVO/g-C3N4 demonstrates superior characteristics compared to PtCo/g-C3N4 and PtCoV/g-C3N4. This superiority can be attributed to the notable influence of oxygen vacancies in HxV2O5 on the electrical properties of the catalyst. By adjusting the relative proportions of metal atoms in the PtCoVO/g-C3N4 nanomaterials, the PtCoVO/g-C3N4 nanocomposites show significant HER overpotential of η10 = 92 mV, a Tafel slope of 65.21 mV dec-1, and outstanding stability (a continuous test lasting 48 h). The nanoarchitecture of a g-C3N4-supported PtCoVO nanoalloy catalyst exhibits exceptional resistance to nanoparticle migration and corrosion, owing to the strong interaction between the metal nanoparticles and the g-C3N4 support. Pt, Co, and V simultaneous doping has been shown by Density Functional Theory (DFT) calculations to enhance the density of states (DOS) at the Fermi level. This augmentation leads to a higher charge density and a reduction in the adsorption energy of intermediates.

Dendritic boron and nitrogen doped high-entropy alloy porous carbon fibers for high-efficiency hydrogen evolution reaction

Among various electrocatalysts, high-entropy alloys (HEAs) have gained significant attention for their unique properties and excellent catalytic activity in the hydrogen evolution reaction (HER). However, the precise synthesis of HEA catalysts in small sizes remains challenging, which limits further improvement in their catalytic performance. In this study, boron- and nitrogen-doped HEA porous carbon nanofibers (HE-BN/PCNF) with an in situ-grown dendritic structure were successfully prepared, inspired by the germination and growth of tree branches. Furthermore, the dendritic fibers constrained the growth of HEA particles, leading to the synthesis of quantum dot-sized (1.67nm) HEA particles, which also provide a pathway for designing HEA quantum dots in the future. This work provides design ideas and guiding suggestions for the preparation of borated HEA fibers with different elemental combinations and for the application of dendritic nanofibers in various fields.

Unravelling the role of work function difference on supported Ru nanoclusters for alkaline hydrogen evolution reaction

Fine tuning the work function difference (ΔΦ) between support and Ru which in turn affects the electron distribution of Ru is an effective method for the design of high-performance alkaline hydrogen evolution reaction (HER) catalysts. However, it remains a challenge to understand the intrinsic relationship between HER activity and ΔΦ at the atomic level. Herein, taking N doped graphene supported Ru nanoclusters (Ru/CxNy) as the theoretical model, we demonstrate that the HER activity can be correlated with the variation of ΔΦ. For Ru/C50 with smaller ΔΦ, we find that the Ru atoms located at the top layer of Ru nanoclusters (Ru-t) with lower coordination numbers are the main reaction sites. For Ru/C30N20 with larger ΔΦ, the stronger charge redistributions of Ru is observed, and the electron-deficient Ru atoms closing to the interface (Ru-i) are the main reaction sites with significant improvement HER activity. Our findings demonstrate the role of ΔΦ on Ru/CxNy systems for the alkaline HER, which can provide valuable theoretical guidance for the design of high efficient HER catalysts.

Accelerating water dissociation at hierarchical nanostructured electrocatalyst for efficient hydrogen evolution

The sluggish kinetics of the water electrolysis reaction is a key issue for hydrogen production, so the rational design of a high-efficiency hydrogen evolution reaction (HER) electrocatalyst with various structures has attracted extensive attention. Herein, a coaxial hierarchical three-dimensional (3D) nanostructure, Pt@Mo–S–Ni-CNTs, was prepared. In this nanostructure, carbon nanotubes (CNTs) as the core, Mo–S–Ni ultrathin nanosheets as shells, and ultrasmall metal nanoparticles (NPs) were grown uniformly on the surface of Mo–S–Ni nanosheets (NSs). At a current density of 10 mA m−2, the catalyst under investigation has remarkable hydrogen evolution reaction (HER) activity under acidic conditions. The overpotential (η10) is measured to be 61.2 mV, while the Tafel slope is determined to be 40.2 mV dec−1. Meanwhile, in an alkaline medium, η10 is 80.5 mV and the Tafel slope is 52.3 mV dec−1. It also shows great mass activities of 1.32 A mg−1 and 1.86 A mg−1, which are higher than those of commercial Pt/C HER catalysts. Impressively, the excellent HER activity and durability of Pt@Mo–S–Ni-CNTs are mainly attributed to the close binding effects among Pt, MoS2, and NiS. Theoretical simulations show that the MoS2/NiS interfaces facilitate H2O dissociation and that Platinum (Pt) enhances the absorption of hydrogen atoms (H) and increases the charge transfer kinetics of the Mo–S–Ni, thus significantly improving the HER activity. This work highlights the importance of engineering interface nanosheets based on transition-metal dichalcogenides for enhanced HER performance.

Modulate the surface charge toward efficient hydrogen evolution reaction: Electronic structure engineering of MoB-Ni3B interface

Rationally regulated the surface electronic structure of catalysts hold the key to enhance the kinetics of hydrogen evolution reaction (HER). Herein, we propose an electronic structure engineering strategy to modulate the surface charge of Ni3B by introducing MoB for high-efficient HER. The MoB-Ni3B interface exhibits characteristic lattice expansion and results in electron modulation between the Ni3B and MoB. Density functional theory calculations further indicate that the introduction of MoB leads to electron enrichment around Ni sites, which further activate Ni sites, weaken the adsorption of hydrogen intermediates and thus facilitate the unfavorable hydrogen desorption, resulting in the Gibbs free adsorption energy closer to zero. As expected, the hierarchical MoB-Ni3B displays an ultra-low overpotential (η10 = 35 and 57 mV for reaching a current density of −10 mA cm−2) in 1.0 M KOH and 0.5 M H2SO4, which is comparable to the commercial Pt catalyst and confirms the positive effect of the modulation of electronic structure on the kinetics and catalytic activity. The effectiveness of the electronic structure engineering strategy is expected to shed light on the construction of more advanced electrocatalysts.

Ultrafine CoRu alloy nanoclusters densely anchored on Nitrogen-Doped graphene nanotubes for a highly efficient hydrogen evolution reaction

Designing highly efficient and stable electrocatalysts for hydrogen evolution reactions (HER) is essential to the production of green and renewable hydrogen. Metal-organic framework (MOF) precursor strategies are promising for the design of excellent electrocatalysts because of their porous architectures and adjustable compositions. In this study, a hydrogen-bonded organic framework (HOF) nanowire was developed as a precursor and template for the controllable and scalable synthesis of CoRu-MOF nanotubes. After calcination in Ar, the CoRu-MOF nanotubes were converted into N-doped graphene (NG) nanotubes with ultrafine CoRu nanoclusters (hereon called Co-xRu@NG-T; x = 0, 5, 10, 15, 25 representing the Ru content of 0–0.25 mmol; T = 400 °C to 700 °C) that were densely encapsulated and isolated on the shell. Taking advantage of the synergistic effects of the porous, one-dimensional hollow structure and ultrafine CoRu nanoclusters, the optimized Co-15Ru@NG-500 catalyst demonstrated superior catalytic performance for HERs in alkaline electrolytes with an overpotential of only 30 mV at 10 mA cm−2 and robust durability for 2000 cycles, which outperforms many typical catalytic materials, such as commercial Pt/C. This work introduces a novel high-efficiency and cost-effective HER catalyst for application in commercial water-splitting electrolysis.

Cactus-like NC/CoxP electrode enables efficient and stable hydrogen evolution for saline water splitting

Designing efficient and robust catalysts for hydrogen evolution reaction (HER) is imperative for saline water electrolysis technology. A catalyst composed of CoxP nanowires array with N-doped carbon nanosheets (NC) was fabricated on Ni foam (NF) by an in-situ growth strategy. The material is designated as NC/CoxP@NF. In the preparation process, Co(OH)2 nanowires were transformed into a metal organic framework of cobalt (ZIF-67) on NF by the dissolution-coordination of endogenous Co2+ and 2-methylimidazole. The resulting cactus-like microstructure gives NC/CoxP@NF abundant exposed active sites and ion transport channels, which improve the HER catalytic reaction kinetics. Furthermore, the interconnected alternating nanowires and free-standing nanosheets in NC/CoxP@NF improve its structural stability, and the formation of surface polyanions (phosphate) and a NC nanosheet protective layer improve the anti-corrosive properties of catalysts. Thus, the NC/CoxP@NF has an excellent performance, requiring overpotentials of 107 and 133 mV for HER to achieve 10 mA cm−2 in 1.0 mol L−1 KOH and 1.0 mol L−1 KOH + 0.5 mol L−1 NaCl, respectively. This in-situ transformation strategy is a new way of constructing highly-efficient HER catalysts for saline water electrolysis.

S dopant-mediated hydrogen evolution reaction activity of CoSe2

CoSe2 has become one of the most appealing non-noble metal catalysts for hydrogen evolution reaction (HER) in the field of electrolysis water due to its abundant resources and good activity. Inversely, its slow kinetic behavior is still restrained, which plays a negative influence for high-efficiency HER. Herein, a certain of Ni or S was introduced into the (100) crystal facet of CoSe2 on the basis of density functional theory (DFT) calculations. Thermodynamic calculation results reveal that the HER activity for CoSe1S1 is relatively better than those of Ni0.375Co0.625Se2 and pristine CoSe2 when a certain of S atoms were introduced into CoSe2. More strikingly, the active sites of CoSe1S1 are reversed from cationic Co to anion S, which is close to the ideal value (0) of Gibbs free energy. Meanwhile, the kinetic performance of H adsorbed on the anionic S or Se site is optimal, and their migration energy barrier is lower in comparison with 1/2 of the cationic Co site. According to the electronic structure analysis, the conductivity of CoSe1S1 is prominent than other counterparts (such as Ni0.375Co0.625Se2 and CoSe2). This work indicates that CoSe1S1 exhibits an excellent catalytic performance for HER, and offers theoretical guidance in the aspect of experiments for designing high-efficient HER catalysts.

MOF-derived CoS2/WS2 electrocatalysts with sulfurized interface for high-efficiency hydrogen evolution reaction: Synthesis, characterization and DFT calculations

Developing high-efficiency, economical and non-noble-metal electrocatalysts is of great importance to produce hydrogen through hydrogen evolution reaction (HER) in water splitting. Transition metal dichalcogenide has received increasing interests in the application in efficient catalysis, energy conversion and storage. Now, a unique bimetallic sulfide composite (CoS2/WS2) has been prepared by calcination and one-pot hydrothermal method using metal–organic frameworks (MOFs) as precursors. The presence of suitable thioacetamide (TAA) plays a great role in forming the best sulfide interface between CoS2 and WS2 to enhance HER performance. Herein, the overpotential and Tafel slope of as-synthesized CoS2/WS2 at 10 mA cm−2 in 0.5 M H2SO4 medium are obtained as 79 mV and 52 mV dec–1, respectively, which are much lower than those of most non-noble metal-based electrocatalysts. Density Functional Theory (DFT) calculations verify that the bimetallic configuration through the sulfide interface changes the electronic structure, enhances the electrical conductivity and reduces the hydrogen adsorption energy (ΔGH*), effectively accelerating the Heyrovsky step in the HER process. Meanwhile, CoS2/WS2 shows excellent stability in durability tests. The method proposed in this work provides a feasible solution for synthesizing low-cost electrocatalysts.

Aluminum-incorporation activates vanadium carbide with electron-rich carbon sites for efficient pH-universal hydrogen evolution reaction

Vanadium carbide (VC) is the greatest potential hydrogen evolution reaction (HER) catalyst because of its platinum-like property and abundant earth reserves. However, it exhibits insufficient catalytic performance due to the unfavorable interaction of reaction intermediates with catalysts. In this work, using NH4VO3 as the main raw material, the flow ratio of CH4 to Ar was accurately controlled, and a non-transition metal Al-doped into VC (100) nano-flowers with carbon hybrids on nickel foams (Al-VC@C/NF) was prepared for the first time as a high-efficiency HER catalyst by chemical vapor carbonization. The overpotential of Al-VC@C/NF catalysts in 0.5 M H2SO4 and 1 M KOH at a current density of 10 mA cm−2 are only 58 mV and 97 mV, respectively, which are the best HER performance among non-noble metal vanadium carbide based catalysts. Simultaneously, Al-VC@C/NF exhibits small Tafel slope (45 mV dec-1 and 73 mV dec-1) and excellent stability in acidic and alkaline media. Theoretical calculations demonstrate that doped Al atoms can induce electron redistribution on the vanadium carbide surface to form electron-rich carbon sites, which significantly reduces the energy barrier during the HER process. This work provides a new tactic to modulate vanadium-based carbons as efficient HER catalysts through non-transition metal doping.

Heterogeneous Cu incorporated into Ni6Fe2-LDH/rGO induces spin exchange interaction to enhance alkaline hydrogen evolution

The efficiency of hydrogen evolution reaction (HER) takes an important influence on electrochemical water electrolysis, yet it still delivers sluggish kinetics mainly due to the high kinetic energy barriers. Herein, Cu1Ni5Fe2-Layered double hydroxides/reduced graphene oxide (denoted as Cu1Ni5Fe2-LDHs/rGO) with heterogeneous Cu atoms incorporated into Ni6Fe2-LDHs/rGO is constructed through a hydrothermal method and doping strategy in this works, wherein the subtle lattice distortion is availably regulated and optimized by Cu2+ Jahn-Teller effect, offering more active sites for HER. As benefits of the subtle lattice distortion and the spin exchange interaction, Cu1Ni5Fe2-LDHs/rGO displays ferromagnetism at room temperature and shows superior alkaline HER properties with a relatively low overpotentials of 50 mV at 10 mA cm−2 in 1.0 M KOH. The low Tafel slope of 38 mV dec−1 implies Cu1Ni5Fe2-LDHs/rGO owns an ultra-fast HER kinetic. This study can offer a new strategy to construct high efficient HER catalysts based on transition metal NiFe-LDHs.

Ruthenium co-anchored by nitrogen and oxygen on lignin derived carbon for high-efficient hydrogen evolution

Developing efficient electrocatalysts for hydrogen evolution reaction (HER) is crucial to hydrogen production by water electrolysis. Ruthenium (Ru) supported on nitrogenated carbon catalysts as well as the active sites on them have been widely investigated in HER. Nevertheless, the loading of Ru is still high and some oxygen species usually exist in the nitrogenated carbon and their roles are seldom discussed. Herein, we report a novel HER catalyst of 2 wt% Ru/CNO that Ru clusters uniformly dispersed on O-rich nitrogenated carbon (O-rich CN) synthesized from renewable lignin and low-cost melamine. In 1.0 M aqueous KOH, it presents low overpotential of 13 mV at 10 mA cm−2, comparing to that of 39 mV on a commercial 20 wt% Pt/C catalyst. In particular, it also exhibits low value of 659 mV and excellent stability at a large current density of 2000 mA cm−2. The combination of various spectroscopic experiments and density functional theory calculations reveals that Ru cluster co-anchored by nitrogen and oxygen is the active site. This study unveils the crucial role of O in nitrogenated carbon to HER and demonstrates a lignin derived carbon as an excellent electrocatalyst support, supplying a strategy for developing high-efficient HER catalysts.

Tuning the interface of MIMII(OH)F@MIMII1-xS (MⅠ: Ni, Co; MⅡ: Co, Fe) by atomic replacement strategy toward high performance overall water splitting

Constructing heterostructure is considered as one of the most promising strategies to reveal high efficiency hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance. Nevertheless, it is highly challenging to obtain stable interfaces and sufficient active sites via conventional method. In addition, Ni, Co and Fe elements share the valence electron structures of 3d6-84s2, the appropriate integration of these metals to induce synergistic effect in multicomponent electrocatalysts can enhance electrochemical activity. Herein, in this work, the MIMII(OH)F@MIMII1-xS (NiFe(OH)F@NiFe1-xS, NiCo(OH)F@NiCo1-xS, CoFe(OH)F@CoFe1-xS) autogenous heterostructure on nickel foam are constructed. As a result, NiFe(OH)F@NiFe1-xS-0.05, NiCo(OH)F@NiCo1-xS-0.05, and CoFe(OH)F@CoFe1-xS-0.05 demonstrate outstanding overpotential for HER (70 mV, 90 mV, 81 mV at −10 mA cm−2) and OER (370 mV, 470 mV, 370 mV at 10 mA cm−2) in alkaline electrolyte, while the overpotential for HER is 176 mV, 189 mV, 167 mV at −10 mA cm−2 and corresponding OER is 290 mV, 390 mV, 300 mV at 10 mA cm−2 in simulated seawater, respectively. In addition, the NiFe, NiCo, CoFe-based electrolyzer acquire favorable overall water splitting activity in alkaline (1.72 V, 1.87 V, 1.66 V) and simulated seawater (1.73 V, 1.75 V, 1.69 V) at 10 mA cm−2. Overall, the above results authenticate the feasibility of developing autogenous heterostructure electrocatalysts for providing hydrogen and oxygen in alkaline and simulated seawater.

Cactus-like (Ni,Co)Se2 nanosheets with 3D structure decorated on the conductive substrate for efficient hydrogen evolution reaction

Transition metal selenides are a fascinating class of substitute for traditional noble metal electrocatalysts for hydrogen evolution reaction (HER). However, the monometallic selenides still have the disadvantages of low electroactive sites and electrical conductivity. To address such drawbacks, three-dimensional (3D) hierarchical nanostructures composed of bimetallic compounds have aroused great attention. In this study, cactus-like bimetallic nickel–cobalt nanosheets with a 3D nanostructure are successfully prepared on the surface of conductive substrate by a one-step hydrothermal reaction. Then a high-efficiency bimetallic catalyst ((Ni,Co)Se2/CFP) is obtained by a facile chemical vapor deposition. Benefiting from bimetallic components and the unique 3D structure, the cactus-like (Ni,Co)Se2/CFP only requires a low overpotential of 154 mV to reach the current density of 10 mA cm−2. The Tafel slope of (Ni,Co)Se2/CFP (67 mV dec−1) further shows that (Ni,Co)Se2/CFP has faster HER kinetics. Besides, the long-term stability test demonstrates the excellent durability of (Ni,Co)Se2/CFP in 0.5 M H2SO4. This research offers a useful technique and guide for improving the structure of bimetallic selenides based on transition metals to design high-efficient HER electrocatalysts.

Greatly Boosting Seawater Hydrogen Evolution by Surface Amorphization and Morphology Engineering on MoO2/Ni3(PO4)2

AbstractHydrogen production through seawater electrolysis faces several challenges, one of which involves the development of electrocatalysts with high catalytic performance. Here, surface amorphization and morphology engineering are combined to design a novel electrocatalyst for highly‐efficient hydrogen evolution reaction (HER). The surface‐amorphized MoO2/Ni3(PO4)2 microcolumns supported on nickel foam (SA‐MoO2/Ni3(PO4)2/NF) display remarkable performance with low overpotentials of 34 and 46 mV at a current density of 10 mA cm−2 in 1 m KOH and alkaline seawater, respectively. In addition, the alkaline electrolysis cell (AEC) integrated with SA‐MoO2/Ni3(PO4)2/NF as the cathode and Ni foam as the anode achieves a current density of 100 mA cm−2 at 1.87 V in 6 m KOH seawater at 60 °C, superior to that of industrial NiMo electrode as cathode (2.05 V). DFT calculations demonstrate that the surface amorphous layer (MoOx) improves the hydrogen adsorption energy of sample and reduces the energy barrier of water dissociation. It is found that substantial improvement in catalytic performance stems from the synergistic effect between surface amorphization and unique microcolumn morphology. These findings may provide insights into combining surface amorphization and morphology engineering strategies to enhance catalytic performance and pave the way for the development of highly efficient seawater HER electrocatalysts.

High-temperature shock enabled synthesis of ultrafine Ru nanoparticles anchoring onto tungsten carbide with strong metal-support interaction for ampere-level current density hydrogen evolution

Developing cost effective, active and durable alternatives to platinum electrocatalysts is the major challenge for sustainable hydrogen production. Rational design and controlled synthesis of hybrid structures with strong metal-support interaction may offer a feasible strategy to achieve efficient and stable hydrogen evolution reaction (HER). Herein, a low cost and high-performance ultrafine Ru nanoparticles anchored tungsten carbide (Ru/WC) HER electrocatalyst is successfully prepared by high-temperature shock (HTS) technology, which can be accomplished in less than 0.5 s. In a strong alkaline medium, the as-prepared Ru/WC exhibits a low overpotential of 4 mV and 72 mV at the current densities of 10 mA cm−2 and 100 mA cm−2, respectively. Low Tafel slope of 44 mV dec−1, high turnover frequency (TOF) of 2.55 s−1 at an overpotential of 100 mV, long-term electrochemical stability up to 150 h, and ampere-level current density can be achieved. Furthermore, Ru/WC also shows exceptional activity and stability under acidic conditions. Notably, Ru/WC can accommodate HER current density as high as 2000 mA cm−2 at a small overpotential of 365 mV, which holds great promises for industrial large-scale production. This work provides a simple, rapid, and solvent-free strategy for synthesizing high efficiency HER electrocatalyst with ampere-level current density.

Low-loading and ultrasmall Ir nanoparticles coupled with Ni/nitrogen-doped carbon nanofibers with Pt-like hydrogen evolution performance in both acidic and alkaline media

The construction of highly active and durable electrocatalysts for hydrogen production from water electrolysis in a wide pH range is crucial for the sustainable development of clean energy. In this work, low-loading and ultrasmall Ir nanoparticles decorated on the surface of Ni/nitrogen-doped carbon nanofibers (NCNFs) are rationally constructed through a simple chemical reduction deposition route. Benefiting from the rich electrochemical active sites and excellent electrical conductivity, the obtained Ni-NCNFs-Ir catalyst exhibits superior hydrogen evolution reaction (HER) activities in both acidic and alkaline solutions. Specifically, the optimized 0.1Ni-NCNFs-5Ir catalyst with Ir content of 6.0 wt% exhibits remarkable low overpotentials of 22 and 25 mV at 10 mA cm−2 in 0.5 M H2SO4 and 1 M KOH, respectively, which are better than many other reported Ir- or Ni-based electrocatalysts. In addition, the prepared 0.1Ni-NCNFs-5Ir catalyst shows favorable durability. Our theoretical results reveal that the relevant C- and Ir-sites jointly contribute to the high HER catalytic property of the Ni-NCNFs-Ir system, and two complicated electron transfer processes (Ni → C → N and Ir → C → N) are beneficial to promote the electrocatalytic performance. This work provides a meaningful strategy to develop high-efficiency HER electrocatalysts in a wide pH range.

In-plane heterostructured MoN/Mo2N nanosheets as high-efficiency electrocatalysts for alkaline hydrogen evolution reaction

Economical and efficient electrocatalysts are crucial to the hydrogen evolution reaction (HER) in water splitting to produce hydrogen. Heterostructured electrocatalysts generally exhibit enhanced HER catalytic activity due to the strong electron coupling effects and synergistic optimization of hydrogen adsorption–desorption. Herein, in-plane heterostructured MoN/Mo2N nanosheets are fabricated as high-efficiency HER electrocatalysts in the alkaline medium from bulk MoS2 by molten salt-assisted synthesis. Density-functional theory calculations and experiments show that the in-plane heterostructured MoN/Mo2N nanosheets facilitate interfacial electron redistribution from Mo2N to MoN, giving rise to more negative H2O adsorption energy and optimal hydrogen adsorption free energy (ΔGH* = −0.017 eV). Consequently, a low overpotential of 126 mV at 10 mA cm−2 and a small Tafel slope of 69.5 mV dec−1 are achieved in the 1M KOH electrolyte, demonstrating excellent HER characteristics. Moreover, the overpotential shows negligible change after operating at 50 mA cm−2 for 12 h, confirming the excellent stability. The results reveal a novel and effective strategy to design highly efficient 2D in-plane heterostructured HER electrocatalysts for water splitting.

Sustainable bacterial cellulose derived composites for high-efficiency hydrogen evolution reaction

Incorporating heteroatoms into carbon structure has been demonstrated to be efficient for hydrogen evolution reaction (HER). However, the preparation complexity and poor durability are insufficient for the future hydrogen economy. In this work, the preparation of ZIF-67/BC precursor with BC as the template was done for the in-situ growth of MOFs (ZIF-67) crystals, followed by the carbonization and phosphating of ZIF-67/BC to prepare the CoP-NC/CBC N-doped composite carbon material with CoP as the primary active material. The results show that as an HER catalyst, CoP-NC/CBC can provide a current density of 10 mA cm−2 at an overpotential of 182 mV in the acidic electrolyte of 0.5 M H2SO4 or the same current density at an overpotential of 151 mV in the alkaline electrolyte of 1.0 M KOH. The work validates a design idea for advanced non-precious metal-based HER catalysts with high activity and stability.