Enhanced Hydrogen Evolution Reaction Activity Research Articles

RuSe2 nanoparticles loaded MoSe2 hybrid rods via interface engineering as an efficient electrocatalyst for hydrogen evolution electrocatalysis

Despite being regarded as a favorable substitute for platinum-based catalysts in hydrogen evolution reaction (HER), molybdenum diselenide (MoSe2) exhibits inferior electrocatalytic performance due to its inadequate conductivity and limited active sites. However, employing molecular engineering for modification holds great potential in significantly enhancing its performance, yet it still poses significant challenges. Herein, an interface engineering strategy was adopted to obtain RuSe2 modified MoSe2 composite catalysts (RuSe2/MoSe2). In alkaline media, RuSe2/MoSe2 exhibited a reduced overpotential of 147.8 mV at 10 mA cm−2 comparing with pristine MoSe2 (351.8 mV). Experimental findings and density functional theory (DFT) calculations indicated that increased conductivity, enhanced hydrophily and optimized adsorption free energies of hydrogen contribute to its enhanced HER activity. This work opens up an interface engineering strategy for designing more efficient selenide-based electrocatalysts.

Porous rod-like structured ternary nitride heterocatalyst Co3Mo3N/Ni3Mo3N for efficient and stable hydrogen evolution reaction

Heterostructure electrocatalysts have garnered widespread attention for effectively enhancing electrocatalytic activity. However, less attention has been paid to ternary nitride heterostructure catalysts for the hydrogen evolution reaction (HER), and their synthesis remains challenging. In this study, a Co3Mo3N/Ni3Mo3N heterostructure catalyst on nickel foam (NF) is designed and prepared via high-temperature nitridation of the heterostructured precursor. The resulting 1D/3D hierarchical structure electrode, featuring rich heterointerfaces, provides abundant active sites, enhancing mass transport and charge transfer. Experimental results reveal strong electronic interactions at the heterointerface, while density functional theory (DFT) calculations establish that Co3Mo3N/Ni3Mo3N possesses a lower water dissociation energy barrier and optimized hydrogen adsorption energy. Consequently, it demonstrates excellent HER performance, exhibiting low overpotentials of 36 mV in alkaline and 58 mV in neutral media at 10 mA cm−2. This study presents an innovative approach to designing ternary nitride heterostructure catalysts with enhanced HER activity, applicable to other heterostructure catalysts.

Strain derived from bubbles at monolayer MoS2/hBN interfaces for enhanced hydrogen evolution reaction activity

Strain derived from bubbles at monolayer MoS2/hBN interfaces for enhanced hydrogen evolution reaction activity

Emergence of electrochemical catalytic activity via an electrochemical-probe on defective transition metal dichalcogenide nanosheets

Two-dimensional transition metal dichalcogenides (2D TMDs) have shown exceptional electrochemical catalytic activity for the efficient generation of hydrogen through electrochemical water splitting. In the case of molybdenum disulfide (MoS2), a prominent member of 2D TMDs, the electrochemically active sites primarily reside at the edges, while the basal plane, which constitutes the majority of the MoS2 structure, remains relatively inactive. In this study, we aimed to activate the inert sites of the basal plane with some defective structure for hydrogen evolution reaction (HER) by employing an electrochemical-probe in combination with voltage sweeping. The initiation of HER at these previously inactive sites was visualized and confirmed using scanning electrochemical cell microscopy (SECCM). Our findings reveal that the enhanced HER activity originates from surface defects induced by the probing process.

Boosting the Electrocatalytic Water Splitting Performance Using Hydrophilic Metal-Organic Framework.

In this study, we employed a rapid and efficient microwave method to synthesize Metal-Organic Framework (MOF-303), which was subsequently embedded onto Palladium/Carbon (Pd/C) electrodes. The resulting hybrid material, Pd/C@MOF-303, was thoroughly characterized, and its performance in the Hydrogen Evolution Reaction (HER) was systematically investigated. The Pd/C@MOF-303 composite exhibited remarkable improvements in HER performance compared to the unmodified Pd/C electrode. At a benchmark current density of 10 mA cm-2, the overpotentials for Pd/C and Pd/C@MOF-303 were measured at 185 mV and 175 mV, respectively. This reduction in overpotential highlights the superior catalytic activity of the Pd/C@MOF-303 hybrid material in facilitating the HER. Furthermore, the Pd/C@MOF-303 electrode demonstrated enhanced HER activity, increased mass activity, and excellent charge transfer rates compared to its unmodified counterpart, Pd/C. The findings underscore the significance of the hydrophilic MOF-303 in tailoring the surface characteristics of electrocatalysts, thereby offering insights into the design principles for advanced materials with superior performance in electrochemical applications.

Enhancing Hydrogen Evolution Reaction Activity of Palladium Catalyst by Immobilization on MXene Nanosheets.

Efficient catalysts with minimal content of catalytically active noble metals are essential for the transition to the clean hydrogen economy. Catalyst supports that can immobilize and stabilize catalytic nanoparticles and facilitate the supply of electrons and reactants to the catalysts are needed. Being hydrophilic and more conductive compared with carbons, MXenes have shown promise as catalyst supports. However, the controlled assembly of their 2D sheets creates a challenge. This study established a lattice engineering approach to regulate the assembly of exfoliated Ti3C2Tx MXene nanosheets with guest cations of various sizes. The enlargement of guest cations led to a decreased interlayer interaction of MXene lamellae and increased surface accessibility, allowing intercalation of Pd nanoparticles. Stabilization of Pd nanoparticles between interlayer-expanded MXene nanosheets improved their electrocatalytic activity. The Pd-immobilized K+-intercalated MXene nanosheets (PdKMX) demonstrated exceptional electrocatalytic performance for the hydrogen evolution reaction with the lowest overpotential of 72 mV (@10 mA cm-2) and the highest turnover frequency of 1.122 s-1 (@ an overpotential of 100 mV), which were superior to those of the state-of-the-art Pd nanoparticle-based electrocatalysts. Weakening of the interlayer interaction during self-assembly with K+ ions led to fewer layers in lamellae and expansion of the MXene in the c direction during Pd anchoring, providing numerous surface-active sites and promoting mass transport. In situ spectroscopic analysis suggests that the effective interfacial electron injection from the Pd nanoparticles strongly immobilized on interlayer-expanded PdKMX may be responsible for the improved electrocatalytic performance.

Efficient electrochemical hydrogen evolution activity of nanostructured Ag3PO4/MoS2 heterogeneous composite catalyst

Hydrogen (H2) generation by electrochemical water splitting is a key technique for sustainable energy applications. Two-dimensional (2D) transition-metal dichalcogenide (MoS2) and silver phosphate (Ag3PO4) possess excellent electrochemical hydrogen evolution reaction (HER) properties when they are combined together as a composite rather than individuals. Reports examining the HER activity by using Ag3PO4, especially, in combination with the 2D layered MoS2 are limited in literature. The weight fraction of MoS2 in Ag3PO4 is optimized for 1, 3, and 5 wt%. The Ag3PO4/1 wt % MoS2 combination exhibits enhanced HER activity with least overpotential of 235 mV among the other samples in the acidic medium. The synergistic effect of optimal nano-scale 2D layered MoS2 structure and Ag3PO4 is essential for creating higher electrochemical active surface area of 217 mF/cm2, and hence this leads to faster reaction kinetics in the HER. This work suggests the advantages of Ag3PO4/1 wt % MoS2 heterogeneous composite catalyst for electrochemical analysis and HER indicating lower resistivity and low Tafel slope value (179 mV/dec) among the prepared catalysts making it a promising candidate for its use in practical energy applications.

Elevating hydrogen evolution performance with plasma-induced sulfur vacancies and heteroatom doping in hollow-structured MnS–CoS catalysts

Transition-metal sulfides doped with various elements show great promise as highly effective catalysts for the hydrogen evolution reaction (HER), potentially serving as alternatives to Pt-based electrocatalysts. Defect engineering has been identified as a key strategy to enhance the HER activity of such catalysts. This study proposes an effective strategy to generate numerous topological/geometric defects on hollow spherical Mn-doped cobalt sulfide (MnS–CoS) via plasma etching. MnS–CoS catalysts with well-defined cavity structures were successfully prepared using a combination of template-assisted and hydrothermal synthesis methods. Under plasma induction, these catalysts exhibited uniformly formed nanocavity structures with a built-in electric field, which uniformly enhanced their topological/geometric defect levels. The plasma-etched MnS–CoS catalyst demonstrated significantly enhanced HER activity, exhibiting an excellent overpotential of 172 mV at a current density of 10 mA·cm⁻2 in alkaline media and a low Tafel slope of 120 mV·dec⁻¹. These improvements can be attributed to the remarkable conductivity of Co and Mn, along with the unique hollow spherical nanostructure of the material, which contained numerous gaps that promoted electron movement and electrolyte penetration, thereby enhancing the overall catalytic performance. The synergistic effects of heteroatom doping and plasma modulation played a crucial role in achieving outstanding catalytic performance toward the HER. Density-functional theory calculations based on a structural model of MnS–CoS-p confirmed that the introduction of defects and heteroatoms reduced hydrogen adsorption: the Gibbs free energy decreased from 0.72 eV for CoS to 0.23 eV for MnS–CoS-p. The excellent HER activity of the MnS–CoS materials stemmed from the abundance of reactive heterostructured interfaces, which optimized the electronic configuration and, thus, accelerated H2O adsorption and dissociation. This study highlights the potential of combining plasma-assisted defect manipulation and transition-metal-element doping to design high-performance catalysts. The findings also offer valuable insights into the development of environment-friendly energy-conversion technologies.

Introducing phosphorus atoms into MoS2 nanosheets through a vapor-phase hydrothermal process for the hydrogen evolution reaction.

Molybdenum disulfide (MoS2)-based electrocatalysts have been considered as promising alternatives to platinum for use in the hydrogen evolution reaction (HER). Developing MoS2 electrocatalysts with more active sites has been recognized as an efficient way to enhance the HER activity. Moreover, phase transition and heteroatom doping show great influence on the HER performance. In this work, we develop a vapor-phase hydrothermal (VPH) approach to introduce phosphorus (P) atoms into a MoS2 nanosheet array on carbon fiber cloth, which presents enhanced HER activity compared with MoS2 without P-doping. The improved performance is due to the synergistic effects of the new active sites formed by the P dopants and the sulfur (S) vacancies in the MoS2 nanosheets generated by the doping of P atoms, which increases the number of active sites. In general, the obtained P-doped MoS2/CFC exhibits a lower onset potential of 80 mV and an overpotential of 162 mV at 10 mA cm-2 than MoS2 without P-doping in 0.5 M H2SO4, accompanied by extremely large cathodic current density and excellent stability. This strategy may open up opportunities for heteroatom doping of electrocatalysts for various applications and provide a new method for material synthesis.

Ferritin cages as building blocks for higher-order assembly through copper-sulfur bonds for HER analysis.

Higher-order assembly of ferritins has been achieved on copper substrate by introducing cysteines on their surfaces with thiol groups as the active moiety. To elucidate the assembly mechanism, Raman spectroscopy was utilized to characterize the interaction between the copper substrate and the modified ferritin, AfFtnAA/E94C. The resulting higher-order architecture shows enhanced hydrogen evolution reaction activity.

First synthesis of RuSn solid-solution alloy nanoparticles and their enhanced hydrogen evolution reaction activity.

Solid-solution alloys based on platinum group metals and p-block metals have attracted much attention due to their promising potential as materials with a continuously fine-tunable electronic structure. Here, we report on the first synthesis of novel solid-solution RuSn alloy nanoparticles (NPs) by electrochemical cyclic voltammetry sweeping of RuSn@SnOx NPs. High-angle annular dark-field scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy maps confirmed the random and homogeneous distribution of Ru and Sn elements in the alloy NPs. Compared with monometallic Ru NPs, the RuSn alloy NPs showed improved hydrogen evolution reaction (HER) performance. The overpotentials of Ru0.94Sn0.06 NPs/C and Ru0.87Sn0.13 NPs/C to achieve a current density of 10 mA cm-2 were 43.41 and 33.19 mV, respectively, which are lower than those of monometallic Ru NPs/C (53.53 mV) and commercial Pt NPs/C (55.77 mV). The valence-band structures of the NPs investigated by hard X-ray photoelectron spectroscopy demonstrated that the d-band centre of RuSn NPs shifted downward compared with that of Ru NPs. X-ray photoelectron spectroscopy and X-ray absorption near-edge structure analyses indicated that in the RuSn alloy NPs, charge transfer occurs from Sn to Ru, which was considered to result in a downward shift of the d-band centre in RuSn NPs and to regulate the adsorption energy of intermediate Hads effectively, and thus enable the RuSn solid-solution alloy NPs to exhibit excellent HER catalytic properties.

Enhancing hydrogen evolution reaction activity through defects and strain engineering in monolayer MoS2.

Molybdenum disulfide (MoS2) has recently emerged as a promising electrocatalyst for the hydrogen evolution reaction (HER). However, the poor in-plane electrical conductivity and inert basal plane activity pose major challenges in realizing its practical application. Herein, we demonstrate a new approach to induce biaxial strain into CVD-grown MoS2 monolayers by draping it over an array of patterned gold nanopillar arrays (AuNAs) as an efficient strategy to enhance its HER activity. We vary the magnitude of applied strain by changing the inter-pillar spacing, and its effect on the HER activity is investigated. To capitalize on the synergistic effect of improved ΔG H via strain engineering and leverage basal plane activation by introduction of sulphur vacancies, we further exposed the strained MoS2 monolayers to oxygen plasma treatment to create S-vacancies. The strained MoS2 on AuNAs with optimal inter-pillar spacing is exposed to oxygen plasma treatment for different durations, and we study its electrocatalytic activity towards the HER using on-chip microcell devices. The strained and vacancy-rich monolayer MoS2 draped on AuNAs with a 0.5 μm inter-pillar spacing and exposed to plasma for 50 s (S0.5μmV50-MoS2) is shown to exhibit remarkable improvement in HER activity, with an overpotential of 53 mV in 0.5 M H2SO4. Thus, the synergistic creation of additional vacancy defects, along with strain-induced active sites, results in enhancement in HER performance of CVD-grown monolayer MoS2. The present study provides a highly promising route for engineering 2D electrocatalysts towards efficient hydrogen evolution.

Sol–Gel Synthesized Nickel‐Doped Ruthenium Oxide Aerogel for Highly Efficient Acidic Hydrogen Evolution Reaction

Solar and wind energy for water electrolysis are gaining interest in contemporary times. In this context, platinum catalysts are commonly recognized as the standard for the hydrogen evolution reaction (HER), yet their effectiveness is constrained by their high cost and inadequate stability. Combining Ru and Ni lowers the material expense and greatly improves the electrocatalytic performance. Therefore, in the present study, a 3D nanostructured amorphous RuO2 aerogel is doped with various concentrations of Ni for enhanced HER activity. The results indicate that the 4% Ni‐RuO2 aerogel exhibits a 0D colloidal network featuring interconnected mesopores, with a high specific surface area of 241.5 m2·g−1. In addition, the 4% Ni‐RuO2 aerogel catalyst exhibits the lowest overpotentials of 63 and 122 mV at current densities of 10 and 50 mA·cm−2, respectively, along with enhanced hydrogen adsorption activity for the HER due to the 3D porous structure of the aerogel. However, a further increase in Ni doping leads to a decrease in HER activity due to a reduction in the number of catalytic Ru sites. The study found that doping with the optimum amount of Ni causes a redistribution of charges on the sample surface, thereby uncovering more reaction sites and enhancing the electrocatalytic performance.

Crystallinity and interfacial Mo–N–C bond engineered MoS2 embedded graphitic nitrogen doped carbon hollow sphere for enhanced HER activity

To restrain fossil fuel depletion, the need of the hour is the development of efficient, durable, and non-precious electrocatalysts for the hydrogen evolution reaction (HER). The hierarchical nanostructure consisting of transition metal dichalcogenides and graphitic heteroatom-doped carbon with an abundant interfacial M–N–C catalytic site is highly demanding for electrolytic applications. Herein, we report crystallinity-engineered ultrathin MoS2 nanosheets hierarchy over nitrogen-doped graphitic carbon (NC) hollow spheres as a promising material for HER. The well optimized NC@MoS2 demonstrates superior HER activity with a low onset overpotential of 9 mV and an overpotential of 145 mV at a current density of −10 mA cm−2. It exhibits low Tafel slope of 39 mV dec−1 and excellent chronoamperometric stability. Superior HER activity originates from interfacial Mo–N–C bonds. Density functional theory (DFT) calculations unveil that Mo–N–C bonds between MoS2 and NC matrix ease electronic transportation and further diminish Gibbs free energy for HER.

Integrated PtxCoy-Hierarchical Carbon Matrix Electrocatalyst for Efficient Hydrogen Evolution Reaction.

Pt-based catalysts are regarded as state-of-the-art electrocatalysts for producing clean hydrogen energy; however, their wide application is restricted by their low abundance, high cost, and poor stability. Herein, we report an integrated PtxCoy-hierarchical carbon matrix electrocatalyst (Pt/Co@NCNTs, Pt3Co@NCNTs, PtCo@NCNTs, and PtCo3@NCNTs) that is developed using a thermally driven Co migration strategy forming alloy nanoparticles to achieve efficient hydrogen evolution reaction (HER). Benefiting from its electronic regulation effect and unique hierarchical hollow structure, the Pt3Co@NCNTs catalyst loaded with 11.5 wt % Pt exhibits superior catalytic performance and durability for HER compared with commercial 20 wt % Pt/C. Under both alkaline and acidic conditions, Pt3Co@NCNTs exhibits excellent HER activity with overpotentials of 21 and 45 mV at 10 mA cm-2, respectively. Density functional theory (DFT) results further verify that the interaction between Pt and Co in Pt3Co@NCNTs can modulate electronic rearrangement, optimize the d-band center, and accelerate water dissociation and *H desorption, thereby enhancing HER activity.

RuIn Solid-Solution Alloy Nanoparticles with Enhanced Hydrogen Evolution Reaction Activity

RuIn Solid-Solution Alloy Nanoparticles with Enhanced Hydrogen Evolution Reaction Activity

Promotion of Sulfur Vacancies and Mn Substitution in Few-Layered Molybdenum Disulfide Towards Superior Hydrogen Evolution in Acid

The superior features of hydrogen as an energy source with high energy density (120 MJ kg-1) and zero CO2 emission, makes it a strong candidate for replacing fossil fuels. Recently the European Commission has pledged to invest €470 billion in renewable hydrogen technologies by 2050, with a significant portion of this investment expected to be allocated for the deployment of renewable hydrogen electrolyzers by 2030. Water electrolysis via Proton Exchange Membrane (PEM) with Pt/Pd-based noble metals as a cathode, is currently the most effective method for hydrogen production, but alternatives are highly needed due to the scarcity and the higher cost of these metals. One of the promising classes of electrocatalysts for hydrogen evolution reaction (HER) is transition metal dichalcogenides (TMDs), and among them molybdenum disulfide (MoS2) has shown promising properties as an electrocatalyst for hydrogen production. MoS2 has different phases of 1T, 2H, and 3R with 2H-MoS2 being the most promising electrocatalyst for hydrogen production due to its semiconductive behavior and long-term stability. However, the poor conductivity, large band gap and no active basal plane towards HER limits the applications of 2H-MoS2 for water electrolysis in PEM cells. Strategies such as introduction of defects, S-vacancies, edge engineering and doping can result in enhanced HER activity of 2H-MoS2. Incorporating different transition metals (Ni, Co, Mn, Fe) into MoS2 lattice can increase the number of active sites and improve charge transfer during the electrocatalytic reaction. Based on Density Functional Theory (DFT) studies, insertion of Mn into MoS2 layer can decrease the bandgap to zero, resulting in large number of available electronic states around the Fermi level. In this work we introduce Mn doped MoS2 produced via a cost-effective microwave-assisted solid-state approach to explore the potential of few-layered MoS2, doped with different levels of manganese (5%, 10% and 15% at.) for HER in acidic media. The electrocatalytic activity towards HER reveals that 10% at. Mn incorporation into MoS2 lattice, reduces the overpotential (η10) from 210 mV for pristine MoS2 to 148 mV for 10%Mn-MoS2, respectively. In addition, Tafel slope analysis has confirmed a faster kinetics of 10%Mn-MoS2 (53 mV dec-1) compared to MoS2 (75 mV dec-1) revealing the Volmer–Heyrovsky mechanism as the rate determining step (rds). Further characterization by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and DFT studies show that Mn substitution promotes the creation of sulfur vacancies, which in turn enhances the catalytic activity towards HER. Additionally, the 10% Mn-doped MoS2 demonstrates remarkable activity in a single-cell PEM electrolyzer with long-term durability. This study highlights the potential of Mn doped MoS2 as an efficient, low-cost electrocatalyst for hydrogen production, with implications for the development of a sustainable hydrogen economy. Figure 1

Tuning Mo Incorporation in Ni-Fe-Mo Solid Solutions: Towards an Improved Hydrogen Adsorption Energy

The production of hydrogen by water electrolysis has emerged as a promising pathway to achieve a 100% renewable and sustainable hydrogen economy. Up to now, alkaline water electrolysis has been highlighted as a truly alternative strategy for hydrogen production due to the usage of non-expensive electrocatalysts. Ni-based electrocatalysts already have a long century history because of high conductivity, stability, and earth abundancy. However, their strong hydrogen interaction energy slows the Hydrogen Evolution Reaction (HER) activity. Tuning the morphology of the catalyst by increasing the active surface area (e.g., production of nanosheets, nanowires, nanoparticles, etc.) and enhancing the intrinsic activity (e.g., doping, alloying, etc.) can improve the catalytic activity. Binary and ternary alloys based on nickel are a common route to boost their intrinsic activity and tune the morphology. Ternary alloys like CuAlNi, NiMoFe and NiMoW have been previously proposed, although the role of each element is still not fully investigated. Among the alloys, Ni-Fe mixtures have shown better catalytic activity towards HER, and the Mo incorporation has resulted in a reduced onset potential due to favorable hydrogen-metal interaction and development of active sites. The strategy for NiFeMo synthesis is mainly by hydrothermal method or electrodeposition which are limited by low material loading and production volume. Therefore, searching for a technique which is capable of producing trimetallic alloys with a scalable amount is of high interest for the development of hydrogen production. Here, we studied the preparation of FeNi3Mox via a fast and straightforward solution precursor plasma spraying (SPPS) method. The liquid precursors containing metal salts of Ni, Fe, and Mo are used to produce trimetallic solid solutions. The non-stoichiometric nanostructured electrocatalysts are deposited onto stainless-steel mesh (SS-mesh), Ni foam, and carbon paper for the HER in alkaline. We found that tuning Mo content (~9 At%) in the solution precursor conducts to an improved overpotential of 112 mV (iR-corrected) at -10 mA cm-2 and a Tafel slope of 109 mV dec-1 in agreement with a Volmer-Heyrovsky HER route. Energy dispersive X-ray spectroscopy (XPS) has confirmed the reduction in the superficial Ni and Fe oxides with Mo insertion which is directly affecting the electron transport. In addition, to investigate the effect of Mo in more detail, we evaluated the work function using ultraviolet photoelectron spectroscopy (UPS) which shows that Mo incorporation changes linearly the electrocatalyst’s work function and it is highly correlated to the hydrogen binding energy. Consequently, the change in the work function, resulting in a weaker hydrogen adsorption energy which leads to an improved hydrogen production. Theoretical catalytic activity maps from Density Functional Theory (DFT) studies have revealed the enhanced HER activity is the responsibility of the active sites near the superficial Mo atoms. Figure 1

Surface reconstruction of RuO2/Co3O4 amorphous-crystalline heterointerface for efficient overall water splitting

The rational construction of amorphous-crystalline heterointerface can effectively improve the activity and stability of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, RuO2/Co3O4 (RCO) amorphous-crystalline heterointerface is prepared via oxidation method. The optimal RCO-10 exhibits low overpotentials of 57 and 231 mV for HER and OER at 10 mA cm−2, respectively. Experimental characterization and density functional theory (DFT) results show that the optimized electronic structure and surface reconstruction endow RCO-10 with excellent catalytic activity. DFT results show that electrons transfer from RuO2 to Co3O4 through the amorphous-crystalline heterointerface, achieving electron redistribution and moving the d-band center upward, which optimizes the adsorption free energy of the hydrogen reaction intermediate. Moreover, the reconstructed Ru/Co(OH)2 during the HER process has low hydrogen adsorption free energy to enhance HER activity. The reconstructed RuO2/CoOOH during the OER process has a low energy barrier for the elementary reaction (O*→*OOH) to enhance OER activity. Furthermore, RCO-10 requires only 1.50 V to drive 10 mA cm−2 and maintains stability over 200 h for overall water splitting. Meanwhile, RCO-10 displays stability for 48 h in alkaline solutions containing 0.5 M NaCl. The amorphous-crystalline heterointerface may bring new breakthroughs in the design of efficient and stable catalysts.

Modulating the electronic structure of MoS2 nanosheets by Mn doping for improving hydrogen evolution reaction: an experimental and theoretical DFT-QTAIM study

This study provides experimental and theoretical analyses of the effects of Mn doping on the electronic structure of MoS2 nanosheets and its impact on the performance of the hydrogen evolution reaction (HER). Experiments show that Mn doping alters the electronic structure of MoS2. This leads to an enhanced HER activity. The Mn-MoS2 nanosheets with a Mn/Mo molar ratio of 1:15 exhibit an overpotential of approximately 238 mV at a current density of 10 mA/cm2 and a low Tafel slope of 68 mV/decade in 0.5 M H2SO4. Density Functional Theory calculations and Bader analysis indicate that the incorporation of Mn atoms into the basal plane of MoS2 nanosheets activates all in-plane S atom sites and three Mo atoms neighboring the Mn dopant, thereby reducing the adsorption free energy of H atoms. Further, the Mn dopant enhances the intrinsic electronic conductivity of MoS2 by reducing its bandgap, which leads to a rapid charge transfer across the basal plane during H2 evolution.