Hydrogen Evolution Reaction Research Articles

Cobalt Incorporation Promotes CO2 Desorption from Nickel Active Sites Encapsulated by Nitrogen-Doped Carbon Nanotubes in Urea-Assisted Water Electrolysis.

The potential application prospects of urea-assisted water electrolysis toward hydrogen production in renewable energy infrastructure can effectively alleviate energy shortages and environmental pollution caused by rich urea wastewater. It is of prominent significance that adjusting the CO2 desorption of nickel-based electrocatalysts can overcome the slow reaction kinetics for urea oxidation reaction (UOR) to achieve exceptional catalytic activity. In this work, cobalt (Co) metal doping is employed to boost the UOR performance of nitrogen-doped carbon nanotubes encapsulating nickel nanoparticle electrocatalysts (Ni@N-CNT). The influence of diverse Co doping concentrations on the performance of UOR and hydrogen evolution reaction (HER) catalytic activities associated with stability are systematically investigated. The Co dopant can effectively promote the dynamical conversion of Ni to Ni3+ species; as a result, the UOR catalytic activity is improved by 1.8-fold at 1.6 V vs RHE. The DFT calculation results show that the CoNi bimetallic structure possesses a comparably lower binding energy for CO2 adsorption accelerating the rate-limiting step. Meanwhile, the Co dopant also boosts the HER performance, achieving a 57 mV reduction in overpotential at 100 mA cm-2 due to the creation of more active sites. In addition, the assembled urea-assisted water electrolysis attains 10 mA cm-2 at merely 1.51 V as well as excellent stability.

Electronic Structure Engineering of NiCoP Sites via N, Ru Dual Doping for Bifunctional Water Electrolysis.

Exploiting highly effective electrocatalysts is a challenge for boosting the overall efficiency of water splitting. Herein, we present a nitrogen and ruthenium dual-doping strategy to tailor the electronic structures of NiCoP(N, Ru-NiCoP), creating high-performance bifunctional electrodes for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The dual-doping approach is favorable for electronic interactions within the NiCoP and CoP, yielding a near-zero Gibbs free energy for H adsorption. Consequently, the optimized N, Ru-NiCoP electrodes exhibit exceptional bifunctional activities, with overpotentials of 53 and 405 mV at 100 mA cm-2 for the HER and OER, respectively. Notably, their performance surpasses that of commercial Pt/C and RuO2 catalysts at large current densities, demonstrating their potential for industrial water splitting applications. Moreover, the overall water-splitting device achieves a current density of 10 mA cm-2 with a driving voltage of only 1.54 V. This work provides an effective heteroatom doping strategy to develop low-cost and highly active electrocatalysts.

Incorporation of graphene quantum dots into magnesium copper phosphate (GQDs-MgCuPO4) for supercapattery and electrocatalysis applications

Abstract We efficiently synthesize magnesium copper phosphate nanoparticles (MgCuPO4) doped with graphene quantum dots (GQDs) using a hydrothermal method for supercapattery and oxygen evolution reactions in KOH electrolyte. The GQDs-MgCuPO4 electrode has a high specific capacity (1188 Cg-1 at 1.0 Ag-1) and a high-rate capability (67%). The symmetric supercapattery (GQDs-MgCuPO4/GQDs-MgCuPO4) provides a staggering energy density of 46 Wh-kg-1, as well as a high-power density of 1300 W-kg-1 and a high cyclic stability of 93% after 10,000 cycles. Furthermore, it demonstrates high efficiency in the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), with corresponding low overpotentials of 181 mV and 119 mV. The GQDs-MgCuPO4 stands out as a capable solution for various energy storage and conversion difficulties.

A Chalcogenide-Derived NiFe2O4 as Highly Efficient and Stable Anode for Anion Exchange Membrane Water Electrolysis.

Developing low-cost, highly active, and durable oxygen evolution reaction (OER) electrodes is one of the critical scientific issues for anion exchange membrane water electrolyzer (AEM-WE). Herein, we report a vacancy-rich and alkali-stable NiFe2O4-type electrode (named as NiFeOx-350-Ov), derived from the chemical-vapor deposited precursor NiFeSexSy-350, as an efficient and robust anode material. The obtained electrode affords current densities of 100 and 500 mA cm-2 at overpotentials of 245 and 270 mV, respectively, and displays excellent long-term durability sustaining 1.0 A cm-2 at least for 1000 h. When coupled with Ni4Mo/MoO2/NF as a hydrogen evolution reaction (HER) catalyst, the resulting platinum-group metal (PGM)-free single-cell AEM-WE exhibits a cell voltage of 1.71 V at the current density of 1000 mA cm-2 at 80 °C and long-term durability during a current-cycling test between 0.5 A cm-2 and 1.0 A cm-2 over 150 h at 60 °C. This work highlights a unique reconstruction strategy for preparing highly active and durable OER catalysts used in PGM-free AEM-WE.

Dynamic Creation of a Local Acid-like Environment for Hydrogen Evolution Reaction in Natural Seawater.

Electrolysis of natural seawater driven by renewable energy is practically attractive for green hydrogen production. However, because precipitation initiated by an increase in local pH near to the cathode deactivates catalysts or blocks electrolyzer channels, limited catalysts are capable of operating with untreated, natural seawater (viz., pH 8.2 to 8.3 and ca. 35 g salts L-1); most are used in strongly alkaline or acidic seawater. Here, we report a new natural seawater electrolysis cathode with precipitation-suppression via a Pt/WO2 catalyst to create a dynamically local acid-like environment. The in situ formed hydrogen tungsten bronze (HxWOy) phase via continuous hydrogen insertion from water acts as a proton reservoir. As a result, dynamically stored protons create a local acid-like environment near the Pt active sites. We evidence that this tailored acid-like environment boosts the hydrogen evolution reaction in natural seawater splitting and neutralizes generated OH- species to restrict precipitation formations. Consequently, a long-term stability of >500 h at 100 mA cm-2 was exhibited in direct seawater electrolysis.

Neutral nickel complexes with tetradentate N-heterocyclic carbene amidate ligands for electrocatalytic hydrogen evolution.

Neutral nickel complexes bearing tetradentate N-heterocyclic carbene (NHC) amidate ligands were prepared; the effect of the electronic properties of the ligand on the redox behavior as well as the electrocatalytic activity for hydrogen evolution reaction (HER) were investigated.

Efficient Hydrogen Evolution Reaction Catalyzed by an N-Heterocyclic Phosphine

Efficient Hydrogen Evolution Reaction Catalyzed by an N-Heterocyclic Phosphine

Enhancing hydrogen evolution reaction efficiency with electrospun Ni-doped Zn(O,S) microfibers photocatalyst: A novel approach for sustainable energy conversion

This study presents Ni-doped Zn(O,S) microfibers as an effective photocatalyst for addressing global energy and environmental challenges by producing green hydrogen as a sustainable alternative to fossil fuels. In addition, the embedment of nanocatalyst into PVP fibers also mitigates the harmful of nanoparticle leaching. Ni-doped Zn(O,S) microfiber photocatalysts with varying Ni concentrations were effectively produced using a simple electrospinning technique, followed by annealing at 180 °C for 3 h. The optimized ZN-2.5 microfiber photocatalyst has achieved the highest hydrogen (H2) production rate of 648.2 μmmol g−1 h−1. ZN-2.5 has recorded 3240.5 μmmol g−1 of hydrogen generation rate after 5 h of illumination in addition to extraordinary stability up to 30 h. This work demonstrates the significant improvement of the overall photocatalytic H2 evolution reaction (HER) process over ZN-X catalysts via doping small amounts of Ni to the Zn(O,S) matrix. Ni doping increases the microfibers light absorbance ability, improves charge separation transfer, and minimizes the recombination rate of the photogenerated electron-hole pairs. Moreover, Ni-doped Zn(O,S) achieved unique stability up to 7 runs for photocatalytic H2 production. More oxygen vacancies are formed on the surface of the photocatalyst upon illumination thus showing elevating activity while recycling the photocatalyst. The reported photocatalysts in this paper are low-cost, earth-abundant, and environment-friendly which is encouraging to design more novel photocatalysts following the same trend.

Different surfaces of copper with single-atom doping for hydrogen evolution reaction in alkaline conditions

The advantages of Cu-based materials make it a potential catalyst for alkaline hydrogen production reactions (HER), but the inertness of pure Cu restricts its application. Thus, it is very meaningful to seek strategies to improve the catalytic activity. In this work, we designed the 15 modified Cu surface models by integrating single atom doping with surface engineering to be used to explore the catalytic activity of Cu surfaces in alkaline HER and the mechanism of effective adsorption and dissociation of water. The results indicated that the combination of surface engineering with single-atom doping can greatly activate the electro-catalysis activity of copper surface. All these 15 catalysts can effectively achieve hydrogen evolution in alkaline conditions, among which the H2O dissociation energy barriers of Cu(210)-Os and Cu(210)-Ru are just 0.47 eV and 0.60 eV, which are much lower than that of pure Pt(111). Thus, it is expected that Cu(210) doped with proper noble metal elements is an ultra-low-cost and ultra1-high-performance catalyst for alkaline HER. Meanwhile, Os and Ru-doped Cu(110) and Cu(211) surfaces also demonstrate remarkable alkaline HER activity compared with the metal catalysts that have been reported hitherto. These offer a novel concept and theoretical guidance to design cheaper and more efficient HER catalysts.

Alkaline Hydrogen Evolution Reaction Electrocatalysts for Anion Exchange Membrane Water Electrolyzers: Progress and Perspective

Alkaline Hydrogen Evolution Reaction Electrocatalysts for Anion Exchange Membrane Water Electrolyzers: Progress and Perspective

High-throughput screening of a transition metal single-atom electrocatalyst for the CH3NO2 reduction reaction

The hydrogenation reduction of nitro compounds involves the wide application of functional amines as important chemical intermediates in the fine chemical industry. However, the development of low-cost, mild reaction conditions and high-performance catalysts for the reduction of nitro compounds is challenging. In this study, the potential of electrocatalysts in which 26 transition metal atoms are anchored to the surface of N-doped graphene (TMN4@G) was explored to determine the mechanism of the electrocatalytic CH3NO2 reduction reaction (CNORR) via density functional theory. First, the stability of TMN4@G was evaluated to screen out the catalyst which is stable at 300 K via ab initio molecular dynamics. Second, the Gibbs free energy with all possible reaction pathways of the CNORR was calculated to search for high-performance catalysts. These results demonstrate that monodentate adsorbed CdN4@G, FeN4@G, CoN4@G and bidentate adsorbed MoN4@G exhibit excellent catalytic activity. The overpotential of MoN4@G is only 0.357 V. Finally, Finally, the role of central metal atom on the catalytic activity of single-atom catalysts in CNORR and the impact of hydrogen evolution reaction on the adsorption of CH3NO2 were further discussed. We hope that this theoretical simulation provides an effective scheme for the reduction of nitro compounds under mild conditions.

High-Entropy Metal Sulfide Promises High-Performance Carbon Dioxide Reduction.

The efficient conversion of carbon dioxide (CO2) requires the development of stable catalysts with high selectivity and reactivity within a wide potential range. Here, the high-entropy metal sulfide CuAgZnSnS4 is designed for CO2 reduction with excellent performance (FEcarbonproducts ≥ 90%) in whole test potential windows (600 mV) based on the synergistic effect of the high-entropy metal sulfide. In particular, CuAgZnSnS4 exhibits better single-product selectivity with the highest FEHCOOH/FECO value (29.03) at -1.28 versus reversible hydrogen electrode (RHE). In combination with in situ measurements and theoretical calculations, it is further revealed that the synergistic effect of CuAgZnSnS4 realizes the controllable regulation of the surface electronic structure at Sn active sites, strengthening orbital interactions between *OCHO and Sn active sites. As a result, the effective adsorption and activation of *OCHO instead of *H are obtained, improving the single-product selectivity of electrocatalytic CO2 reduction and inhibiting the competitive hydrogen evolution reaction significantly. Our findings may complete the understanding of the synergistic effect for high-entropy materials in catalysis and offer new insight into the design of efficient electrocatalysts with high catalytic activity.

Chemically grown Bi2MoX6 (X = O, S, and Se) nanostructures for efficient electrochemical hydrogen evolution reaction

Here, we present the fabrication of an effective and chemical bath deposition (CBD) of Bi2MoX6 (X = O, S, and Se) electrocatalyst for efficient electrochemical hydrogen evolution reaction (HER) activity. To enhance the electrochemical activity of Bi2MoO6 (BMO) electrode, the influence of sulfurization and selenization on the wet chemically synthesized BMO has been extensively studied here. These BMO, Bi2MoS6 (BMS), and Bi2MoSe6 (BMSe) nanostructured developed on nickel-foam are synthesized by a mild two-stage reaction process; a CBD following a sulfo-selenization procedure on BMO. Compared to BMO and BMS electrocatalysts, the BMSe has shown a higher HER activity through a lower overpotential about 120 mV at 10 mA cm−2 and a lower value of Tafel slope (57 mV dec−1). Surface morphology analysis endows hydrangea flower-type petals, nanosheets, and E. coli bacteria-type surface morphologies for BMO, BMS, and BMSe electrocatalysts, respectively. Thus, this article gives an easy tactic for enhancing the electrochemical HER activity of the BMO through the process of sulfurization/selenization at room temperature (25–27 °C).

Manipulating interfacial charge redistribution in Mott-Schottky electrocatalyst for high-performance water/seawater splitting

Interface engineering is an effective approach towards developing low-cost highly efficientelectrocatalystsforgreen hydrogen productionin alkaline water or seawater environments. Herein, we have successfully fabricatedan interface engineered Mott-Schottky heterostructure catalyst i.e.,Fe3O4@Ni3S2, in which, Ni3S2 nanosheets are evenly dispersed on the surface of Fe3O4 flower-like nanosheets, which are supported by a Ni foam substrate. Due to the synergistic effect between Ni3S2 and Fe3O4, theFe3O4@Ni3S2 heterostructure catalystdemonstrates remarkable catalytic activity under alkaline conditions whichis attributed to thehighlyexposed active sites, adjustment of the d-band center, and the built-in electric field at the interface. The catalyst Fe3O4@Ni3S2 has low overpotentials of 207 and 217 mV for the OER (oxygen evolution reaction) and 99 and 118 mV for the HER (hydrogen evolution reaction) in alkaline and seawater electrolytes, respectively, allowing it to yield a current density of 10 mA cm−2. Furthermore, the Fe3O4@Ni3S2||Fe3O4@Ni3S2 electrolyzer can achieve a current density of 10 mA cm−2 for alkaline fresh water and seawater (1 M KOH + seawater) electrolysis at low voltages of 1.57 V and 1.58 V, respectively. This study presents a novel approach for fabricating high-performance multi-interface 3D catalysts for overall water/seawater splitting.

Dual-synergistic effect of medium-entropy metal sulfoselenide nanoparticles toward efficient overall seawater splitting

Developing efficient and durable electrodes for overall water splitting (OWS) in seawater electrolytes is a major challenge. Herein, we synthesized highly active and stable Fe1.2(CoNi)1.8S3Se3 medium-entropy metal sulfoselenide (MESSe) nanoparticles for the electrodes. The Fe1.2(CoNi)1.8S3Se3 MESSe electrode exhibited excellent electrocatalytic performance in alkaline simulated seawater, with a η100 value of 156 mV for the hydrogen evolution reaction and 262 mV for the oxygen evolution reaction. Compared to Fe1.2(CoNi)1.8S6 sulfide and Fe1.2(CoNi)1.8Se6 selenide, the electronic structure of Fe1.2(CoNi)1.8S3Se3 MESSe positively modulates the adsorption/desorption process of *H/*OH intermediate and significantly reduces the free energy of the rate-determining step, thereby accelerating the reaction kinetics of both hydrogen/oxygen evolution reactions. The performance of OWS is significantly enhanced by utilizing the prepared electrode, enabling it to achieve 100 mA cm−2 with only 1.77 V in alkaline simulated seawater. Furthermore, the durability of the electrode is maintained at this high current density in alkaline simulated seawater, alkaline seawater as well as seawater electrolyte. This work will lay the foundation for the development of innovative medium-entropy metal sulfoselenides, promoting their application in a wide range of electrochemical energy systems operating under extreme conditions.

Constructing 3D Crosslinked Macromolecular Networks as a Highly Efficient Interface Layer for Ultra-Stable Zn Metal Anodes.

Aqueous zinc ion batteries (AZIBs) are experiencing rapid development due to their high theoretical capacity, abundant zinc resources, and intrinsic safety. However, the progress of AZIBs is hindered by uncontrollable parasitic reactions and excessive dendrite growth, which compromise the durability and effective utilization of zinc metal anodes. To address these challenges, the study has constructed a 3D crosslinked macromolecular network composed of zinc ion-bonded potato starch (StZ) as an interface layer on Zn foil (StZ-Zn) to inhibit hydrogen evolution, regulate Zn2+ flux, and ensure uniform Zn deposition. Density functional theory calculations, molecular dynamics simulations, COMSOL Multiphysics simulations, and in situ Raman spectra demonstrate that the 3D StZ interface layer facilitates Zn2+ desolvation by restructuring the solvation shells. This process reduces the concentration of H2O at the anode, thereby inhibiting the hydrogen evolution reaction. Consequently, Zn2+ transport is more efficient, promoting a homogeneous Zn2+ flux and enabling dendrite-free Zn deposition. As a result, StZ-Zn||StZ-Zn symmetric cell delivers a superb lifespan of 4800 h at the current density of 5 mA cm-2, and the corresponding cumulative capacity is as high as 12000 mAh cm-2. Notably, StZ-Zn||NaV3O8·1.5H2O full cell can stably operate for 2500 cycles at 5 A g-1 with an outstanding capacity retention of 92%.

Transition Metal Anchored Novel Holey Boron Nitride Analogues as Single-Atom Catalysts for the Hydrogen Evolution Reaction.

The increasing global energy demand and environmental pollution necessitate the development of alternative, sustainable energy sources. Hydrogen production through electrochemical methods offers a carbon-free energy solution. In this study, we have designed novel boron nitride analogues (BNyne) and investigated their stability and electronic properties. Furthermore, the incorporation of transition metals (TM) at holey sites in these analogues was explored, revealing their potential as promising electrocatalysts for the hydrogen evolution reaction (HER). The inclusion of transition metals significantly enhances their structural stability and electronic properties. The TM-anchored BNynes exhibit optimal Gibbs free energy changes (ΔGH) for effective HER performance. Additionally, the favorable alignment of d-band centers near the Fermi level supports efficient hydrogen adsorption. Machine learning models, particularly the Random Forest model, have also been employed to predict ΔGH values with high accuracy, capturing the complex relationships between material properties and HER efficiency. This dual approach underscores the importance of integrating advanced computational techniques with material design to accelerate the discovery of effective HER catalysts. Our findings highlight the potential of these tailored boron nitride analogues to enhance electrocatalytic applications and improve HER efficiency.

Electrocatalytic water splitting by bifunctional Zircon-doped borophene

Oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are crucial for renewable energy technologies such as water splitting. Borophene, a two-dimensional (2D) boron material, has attracted significant interest for its unique electron deficiency and potential applications in energy conversion. However, practical studies on borophene’s electrocatalytic performance remain limited. Here, we demonstrate a strategy to enhance the bifunctional electrocatalytic activity in HER and OER of borophene by doping with zirconium compounds. The addition of Zr to boron enhances electrocatalytic properties by improving performance in both OER and HER, achieving overpotentials and Tafel slopes of 252 and 240 mV, 43 and 203 mV/dec, respectively. Additionally, conducting the measurements at 40 °C led to achieving the overall water-splitting potential of 1.541 (V vs. RHE). Stability tests over 1000 h at ± 10 mA/cm2 highlight the composite’s robustness, outperforming Pt/C in HER and matching the stability of RuO2 in OER. Ex-situ analyses: X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and X-ray diffraction (XRD) reveal insights into the chemical structure evolution during the electrochemical process. This study not only advances the understanding of borophene’s electrocatalytic mechanisms but also paves the way for its application in efficient and sustainable energy technologies.

Self‐Supported Metallic Alkaline Hydrogen Evolution Electrocatalysts Tolerant for Ampere‐Level Current Densities

AbstractElectrocatalytic water splitting is an attractive approach for large‐scale hydrogen generation, critical for global carbon neutrality. However, the prevalent commercialized alkaline water electrolysis is generally conducted at low current densities due to sluggish kinetics and high overpotential, severely hampering high‐efficiency hydrogen production. Exploration of hydrogen evolution reaction (HER) electrocatalysts that can reliably operate at ampere‐level current densities under low overpotentials is thus a primary challenge. In contrast to extensive studies using powdery electrocatalysts, the self‐supported metallic catalytic cathode has become a burgeoning direction toward ampere‐level current densities, owing to their integrated design with intensive interfacial binding, high conductivity and mechanical stability with industrial tolerance/adaption. Recent years have witnessed tremendous research advances in designing self‐supported metallic electrocatalysts. Therefore, this flourishing area is specially summarized. Beginning with the introduction to the theory and mechanism of alkaline HER, the engineering strategies on self‐supported metallic electrodes are systematically summarized, including metal and alloy construction, heterostructure engineering, doping manipulation, and surface design. Meanwhile, particular emphasis is focused on the relationship between structure, activity, and stability under ampere‐level HER. Finally, the existing challenges, requirements of industrial‐scale application, and future direction for designing electrocatalysts are summarized, aiming to provide a better solution for industrial alkaline water electrolysis.

Beneficial surface defect engineering of MoS2 electrocatalyst for efficient hydrogen evolution reaction

Hydrogen evolution reaction (HER) is considered the most efficient method for hydrogen production using an effective electrocatalyst. Molybdenum disulfide (MoS2), with its unique 2D layered structure, is the most promising electrocatalyst. This is attributed to its flexibility, which facilitates the exploration of various MoS2 phases and properties, closely mirroring those of platinum, particularly its Gibbs energy (ΔGH* ̃ 0.08 eV), which makes MoS2 an excellent electrocatalyst. However, its low electrical conductivity and inert basal planes limit its effectiveness for HER. This study utilized a facile hot-gun approach to successfully introduce sulfur vacancies, simultaneously incorporating oxygen from the air, which partially occupied these vacancies. This process resulted in the formation of an intermediate MoOxSy interlayer, yielding a highly effective electrocatalyst. Exposure to the hot gun for a short duration led to several changes, notably expanding the interlayer spacing and altering the atomic S:O ratio from approximately 75 % to 57 %, primarily affecting the MoS2 structure. The optimal duration for hot-gun treatment was determined to be 30 s, enhancing electrochemical activity for HER, with an overpotential of 486 mV vs. RHE (briefly marked as VRHE) at a current density of 10 mA·cm−2 and Tafel slope of 224 mV·dec-1. The improvement in basal active sites, attributable to the formation of defects from sulfur vacancies and partial passivation by oxygen at these sites, was identified as the key factor for this enhanced performance.