Electrocatalytic Activity For Hydrogen Evolution Reaction Research Articles

Effect of Nitrogen and Phosphorus Doping of Reduced Graphene Oxide in the Hydrogen Evolution Catalytic Activity of Supported Ru Nanoparticles.

Three different cathodic materials for the hydrogen evolution reaction (HER) consisting of Ru nanoparticles (NPs) supported onto a bare and two doped reduced graphene oxides (r-GO) have been studied. Ru NPs have been synthesized in situ by means of the organometallic approach in the presence of each reduced graphene support (bare (rGO), N-doped (NH2-rGO) and P-doped (P-rGO)). (HR)TEM, EDX, EA, ICP-OES, XPS, Raman and NMR techniques have been used to fully characterize the obtained rGO-supported Ru materials. These materials have been deposited onto a glassy carbon rotating disk electrode (GC-RDE) to assess their HER electrocatalytic activity at acidic pH. The results show that all three materials are stable under reductive conditions for at least 12 h, and that the heteroatom-doping of the graphene structure extremely increases the activity of the electrodes, especially for the case of Ru@P-rGO, where the overpotential at -10 mA·cm-2 decreases to only 2 mV. Realistic (based on experimental compositional data) modeling of the three rGO supports combined with DFT computational analysis of the electronic and electrocatalytic properties of the hybrid nanocatalysts allows attributing the observed electrocatalytic performances to a combination of interrelated factors such as the distance of the Ru atoms to the dopped rGO support and the hydride content at the Ru NP surface.

Synergistic Contribution of the Strain and Magnetic Field in Ferromagnetic NiMnIn Heusler Alloy Films for the Hydrogen Evolution Reaction.

The external field-assisted hydrogen evolution reaction (HER), beyond modifying electrocatalysts themselves, has garnered significant research attention. However, achieving synergy between multiple fields to enhance the HER performance remains challenging and is not well-explored. Here, NiMnIn Heusler alloy thin films are fabricated using pulsed laser deposition on flexional Cu substrates. Due to the different adsorption free energy under tensile strain (TS) and compressive strain (CS), the most significant enhancement of the electrocatalytic HER activities for the NiMnIn film is observed in the 1.9% TS state, while the CS state of the NiMnIn film shows negative effects. Furthermore, when an external magnetic field is coupled to the 1.9% tensile-strained NiMnIn film, the total overpotential is reduced by 28.6% at a current density of -50 mA cm-2. This improvement is attributed to a synergistic effect that enhances the H adsorption stability and accelerates the H2 desorption process. This work demonstrates the effectiveness of combining multiple external fields and presents a promising strategy for advancing electrocatalysis.

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.

Polyimide-based triazine-cored covalent organic frameworks supported metal (Fe, Ni, Ru and Rh) nanoparticles for high-efficiency electrocatalytic hydrogen evolution

Covalent organic frameworks (COFs) have great potential in electrocatalytic hydrogen evolution reaction (HER). Nevertheless, it is a challenging task to fabricate COF-based electrocatalysts with low overpotential and high stability for HER in acidic media. Herein, a series of polyimide-based triazine-cored COFs (PIT-COFs) with different aromatic diimides are designed to support metal (Fe, Ni, Ru and Rh) nanoparticles for electrocatalytic HER. PIT-COFs are obtained by the reaction between melamine and aromatic (benzene, biphenyl, naphthalene and perylene) diimides. PIT-COFs based on perylenediimide show the optimal electrocatalytic HER activity in acidic media due to its large π-conjugated structure. Rh@COFMA-PT has a low overpotential value of 70 mV at 10 mA cm−2 and a small Tafel slope of 56.58 mV dec−1, which surpasses numerous previously published HER electrocatalysts. Furthermore, Rh@COFMA-PT exhibits good electrocatalytic stability and still keeps high activity after 3000 cycles. The conjugated nitrogen-rich structures of PIT-COFs and their ability to effectively anchor metal nanoparticles as active sites significantly promote the electron and proton transport during the electrocatalytic HER process. This work offers a guideline for developing effective and stable COF-based HER electrocatalysts with abundant active sites.

Electrocatalytic Applications in Hydrogen Evolution of Two Nitrogen Heterocyclic Cu(I) Coordination Polymer Modified Electrodes

ABSTRACTThe development of low‐cost, high‐efficiency, stable, and structurally adjustable electrocatalysts for hydrogen evolution reaction (HER) is of great significance for energy conversion. In this study, two new Cu(I) coordination polymers (CPs), formulated as {[Cu(L1)](PF6)·CH2Cl2}n (1) and {[Cu2(L2)1.5(PPh3)](PF6)2}n (2) (L1 = 1,3‐bis[1‐(pyridin‐3‐ylmethyl) ‐1H‐benzimidazol‐2‐yl]propane, L2 = 1,4‐bis[1‐(3‐pyridylmethyl)‐1H‐benzimidazol‐2‐yl]butane), were synthesized by interfacial diffusion method and characterized by single‐crystal x‐ray diffraction and IR and UV–Vis spectra. Structural analysis shows that the CP‐1 is a one‐dimensional chain structure, whereas the CP‐2 is a two‐dimensional layered structure, which is due to the different coordination modes of ligands L1 (bridging chelation) and L2 (bridging). The electrocatalytic activity for HER of Cu(I) CPs was studied by preparing modified glassy carbon electrodes (CP‐1/GCE and CP‐2/GCE). Electrochemical HER studies manifest that in 0.5 M H2SO4, the overpotential (η10298K) and Tafel slope (b 298K) are −769 mV and 173 mV dec−1 for CP‐1/GCE, −933 mV and 301 mV dec−1 for CP‐2/GCE, and −930 mV and 298 mV dec−1 for bare/GCE, respectively. The η10298K and b298K of CP‐1/GCE were significantly positive shifted and decreased compared with the bare/GCE, indicating that CP‐1/GCE has significant electrocatalytic activity and electrocatalytic HER activity order is CP‐1/GCE > CP‐2/GCE ≈ bare/GCE. This work provides an important reference for the application of non‐noble metal CPs in the field of electrocatalysis.

Glassy Carbon Electrodes Modified with Ru Nanoparticles Loaded in B-Doped Imidazolium Porous Organic Polymers for Hydrogen Evolution Reaction.

Porous organic polymers (POPs) are a type of porous material composed of organic structural units connected by covalent bonds and POPs have been used as efficient electrocatalysts for hydrogen evolution reaction (HER). Herein, glassy carbon electrode (GCE) is chemically modified by B-doped imidazolium-based porous organic polymers loaded with Ru nanoparticles on the GCE surface. The incorporation of B in the POPs regulates the electronic structure of electrocatalysts to enhance their inherent electrocatalytic activity for HER. The optimized modified electrode GCE-Ru/PIM-Br2 exhibits a low overpotential of 271 mV at a current density of 10 mA cm-2 with a small Tafel slope (80 mV dec-1) in acidic solutions, and shows long-term stability for up to 22 h. This work presents a strategy to develop B-doped porous electrodes with loaded metal nanoparticles to strengthen the catalytic performance of electrocatalysts.

Three new cuprous coordination polymers for electrocatalytic hydrogen evolution and glucose sensing performance studies

In this work, three structurally distinct cuprous coordination polymers (CPs), formulated as{[Cu(L1)]ClO4·2CH2Cl2}n (1), {[Cu(L2)(CH3CN)]ClO4}n (2) and {[Cu2(L2)1.5(PPh3)](ClO4)2}n (3) (L1 = (2,2′-(1,3-propanediyl)-6,6′-bis(3- methylpyridine)bis-1,3-benzimidazole, L2 = (2,2′-(1,4-butanediyl)-7,7′-bis(3- methylpyridine)bis-1,3-benzimidazole), have been synthesized by interfacial diffusion methods. Analysis of the single-crystal structure shows that CPs 1–2 are both one-dimensional chain structures, while CP 3 is a two-dimensional layered structure. The electrocatalytic hydrogen evolution reaction (HER) of modified glassy carbon electrodes (CP 1–3/GCE) prepared by mixing acetylene black with CPs 1–3 was studied in 0.5 M H2SO4 electrolyte. The HER measurements show that the overpotential (η10298K) and Tafel slopes (b) of the CP 1–3/GCE are -683 mV and 140.8 mV·dec−1, -779 mV and 168.2 mV·dec−1, -936 mV and 297.4 mV·dec−1, respectively. Compared with the blank electrode (bare/GCE, overpotential -930 mV and Tafel slope 297.9 mV dec−1), the results showed that CP 1–2/GCE had significant electrocatalytic HER activity, whereas CP 3/GCE showed almost no difference in performance with bare/GCE, with electrocatalytic HER activity order being CP 1/GCE > CP 2/GCE > CP 3/GCE ≈ bare/GCE, which depends on the coordination environment of cuprous. In addition, the recognition performance of CP 1–3/GCE on glucose was also investigated using the chronocurrent method in 0.1 M NaOH. The results showed that all CP 1–3/GCE possessed specific recognition properties for glucose with detection limits of 0.030, 0.033 and 0.137 μM in the response range of 0.5 μM ∼ 4.0 mM, and also exhibited long-term stability and good selectivity. This study provides an important reference value for the development of electrocatalysts with cuprous coordination polymers in the field of electrocatalysis.

Hydrogen Evolution Activity of Platinum Nanoparticles Decorated on Silver Nanowire Networks and Graphite Electrodes

The catalytic activity of graphite (C) and conductive silver nanowire (AgNW) networks coated on glass and graphite substrates with low platinum content towards hydrogen evolution reaction (HER) is reported. The results exhibit that the chronoamperometric electrodeposition of platinum on AgNW substrates results in the formation of spherically shaped nanoparticle agglomerates aligned on the nanowires. Also, platinum doped graphite electrodes with a rough surface showed an efficient distribution of platinum nanoparticles (PtNPs). Studies of the electrocatalytic HER activity as a function of platinum loading indicate that the optimum loading is in the range of 60 µg/cm2 and further loading results only in a minor reduction of the overpotential. At low Pt content, a synergistic effect of the AgNW network in terms of enhancement of the HER performance was observed. Tafel analysis showed that in the low overpotential region, the Volmer reaction was the rate determining step for the graphite based electrodes. The graphite substrate in conductive connection with the nanowires was shown to significantly boost the hydrogen formation rate.

Activation of stannic oxide by the incorporation of ruthenium oxide nanoparticles for efficient hydrogen evolution reaction

The demand for clean energy has been increasing rapidly in recent years, and hydrogen is one of the most promising fuels due to its high energy density and clean combustion. The hydrogen evolution reaction (HER) is a key process for hydrogen production, and developing efficient electrocatalysts is essential for HER. While this research is of great interest, it is still challenging to select an ideal material for electrochemical HER in an acidic condition. In this article, SnO2 is activated through the incorporation of a small amount of ruthenium oxide nanoparticles, serving as an auspicious catalyst characterized by exceptional catalytic stability in an acidic medium, outstanding charge transport ability, and abundance of active sites. Herein, the RuO2-SnO2 nanocomposite is synthesized through the precipitation method and characterized using XRD, XPS, TEM, EDX, and BET techniques. The electrochemical results show that the nanocomposite of 0.5 wt% RuO2/SnO2 has excellent electrocatalytic activity for HER, as evidenced by lower charge transfer resistance (0.08 kΩ), low onset potential (−0.02 V), and high Faradaic efficiency (97 %). It demonstrates a substantially reduced overpotential of 237 mV to reach a current density of 10 mA cm−2, alongside a minimal Tafel slope of 117 mV dec−1. The findings of the research will provide a promising strategy to design and synthesize high-performing catalysts for HER.

Sulfur vacancy riched pure 2H phase VS2 for efficient electrocatalytic hydrogen evolution

Vanadium disulfide (VS2), a typical metallic layered transition metal chalcogenide (TMC), has been widely concerned for its high electrical conductivity and reactivity in electrochemical energy storage and conversion applications. The 2H phase VS2 is expected to exhibit high electrocatalytic activity and be more stable for hydrogen evolution reaction (HER) than the 1T phase structure. But at present, there still lacks a facile method to prepare pure 2H phase VS2. Herein, we successfully prepared pure 2H–VS2 through a simple one-step low-temperature hydrothermal method. We have investigated the effect of the hydrothermal reaction conditions (including the proportion of raw materials and hydrothermal reaction temperatures) on the phase composition and microstructure. Under the optimal condition of 140°C-24 h with a vanadium sulfur ratio of 1:5, a nano-flower-like 2H–VS2 material with high crystallinity and rich sulfur vacancy defects was obtained. Leveraging these structural advantages, as a demonstration, the product exhibits excellent electrocatalytic HER activity (with η10 of 181 mV, Tafel slope of 52 mV dec−1, and J0 of 67.9 × 10−3 mA cm−2) and stability (it can continuously produce hydrogen for 20 h at a current density of 50 mA cm−2 with ultra-small increased potential of less than 5 mV). This work provides a new way for constructing atomic vacancy defects in layered TMCs for efficient electrocatalysis and is also expected to promote the research of the basic properties of high phase purity TMCs.

Beyond S and Se: Electrocatalytic Hydrogen Production by Tellurolate-Bridged Co(III)-Mn(I) Heterodinuclear Complexes.

In the pursuit of efficient electrocatalysts for the hydrogen evolution reaction (HER), a series of manganese and cobalt heterodinuclear complexes have been synthesized and characterized that have a stark resemblance with the [NiFe]-hydrogenase active site structure. Irradiation of [Mn2(CO)10] in the presence of 1.5 eq of [NaEPh] [E = S, Se, Te] followed by reaction with [Cp*CoCl]2 led to the formation of half-sandwiched trichalcogenate-bridged heterodinuclear complexes [{Mn(CO)3}(μ-EPh)3(CoCp*)] [E = S (C1); Se (C2) and Te (C3)]. The reaction of these heterodinuclear trichalcogenate-bridged complexes with [LiBH4·THF] yielded the corresponding dichalcogenate hydride-bridged heterobimetallic complexes [(CO)3Mn(μ-EPh)2(μ-H)(CoCp*)] [E = S (C5); Se (C6) and Te (C7)], which closely imitate the Ni-R intermediate of [NiFe]-hydrogenase. The resultant complexes (C5-C7) displayed impressive H2 production in DMF in the presence of HBF4, whereas the Te-based complex (C7) showcased the highest TON (184 h-1) with an impressive Faradaic efficiency of >98%. The DFT investigations revealed a unique role of bridging chalcogens in catalysis, wherein, depending on the identity of the chalcogen (S, Se, or Te), protonation could occur via two distinct routes. This study represents a rare example of the full trio of S/Se/Te-based heterodinuclear complexes whose electrocatalytic HER activity has been probed under analogous conditions.

Rapid Joule heating fabrication of Ru cluster-loaded WO3 on carbon nanotubes to enhance alkaline electrocatalytic hydrogen production activity

The design of efficient electrocatalysts for hydrogen evolution reaction (HER) suitable for industrial applications remains a challenging task. In this work, Ru clusters were loaded onto WO3 which were grown on carbon nanotubes (WRu/C-JH) using a rapid Joule heating method. The crystal phases of WO3 was transformed, and abundant active sites were exposed during the rapid heating and cooling process. All these modifications contributed to the greatly improved electrocatalytic activity in HER. As tested, in 1 M KOH, it only required an overpotential of 22 mV to reach 10 mA cm−2 and 401 mV to reach a high current density of 1 A cm−2 on WRu/C-JH. Moreover, WRu/C-JH demonstrated excellent stability at 500 mA cm−2 for 100 h. Furthermore, a two-electrode system was constructed to assess overall water splitting performance of WRu/C-JH. This system was capable of reaching 100 mA cm−2 at a low voltage of 1.94 V. The mechanism of the enhancement in HER for as-prepared sample was also deeply discussed.

P-doped MoS2 nanosheets embedded in 3D porous carbon for electrocatalytic hydrogen evolution reaction

Due to its inherent electrochemical catalytic activity, molybdenum sulfide (MoS2) is a potential electrocatalyst for hydrogen evolution reaction (HER). However, the limited exposure of its active sites resulting from the easy stacking of nanosheets and inert basal plane hampered its optimal catalytic activity. Herein, we developed a novel facile hydrothermal method to prepare phosphorus-doped MoS2 nanosheets anchored on agar-derived 3D nitrogen-doped porous carbon (P-MoS2/NC). The synthesized P-MoS2/NC electrocatalyst possesses high HER catalytic activity with a low overpotential of 167 mV at 10 mA cm−2 and a small Tafel slope of 45 mV dec−1. The excellent performance is attributed to the unique 3D network carbon structure, which avoids the stacking of the MoS2 sheets resulting in more exposed active sites. Additionally, the P atom introduced on the surface of MoS2 sheets successfully activated the in-plane inertness. This work provides an efficient strategy for designing and preparing high-quality catalysts with enhanced electrocatalytic HER activity.

Synergy of {Co(H2O)6}2+ with a Polyoxometalate Leads to Aqueous Homogeneous Hydrogen Evolution: Experiments and Computations.

In this work, we have described a polyoxometalate (POM)-based inexpensive and easily synthesizable compound [Co(H2O)6]2[{K(H2O)}2V10O28]·2H2O (1), which exhibits electrocatalytic hydrogen evolution in its aqueous solution without its decomposition (or electrodeposition), acting as a rare homogeneous electrocatalyst. Even though the compound [Co(H2O)6]2[{K(H2O)}2V10O28]·2H2O (1) (soluble in water) shows electrocatalytic hydrogen evolution reaction (HER) activity because of the Coulombic attraction, including H-bonding interactions, between the [Co(H2O)6]2+ cationic species and [{K(H2O)}2V10O28]4-anionic species, the individual homogeneous solutions of [V10O28]6- (source: Na6[V10O28]·18H2O) and [Co(H2O)6]2+ (source: CoCl2·6H2O) do not show any electrocatalytic HER activity. We have thus established that the synergy of [V10O28]6- with [Co(H2O)6]2+ in crystal matrix as well as in the aqueous solution of 1 makes the compound 1 a stable and highly active electrocatalyst for homogeneous HER in an aqueous solution. In order to corroborate these homogeneous HER studies, we performed density functional theory (DFT) calculations to show that decavanadate cluster anion [V10O28]6- interacts with hexa-aqua complex cation [Co(H2O)6]2+ via strong H-bonding interactions, leading to a synergy effect that enables the cobalt center of [Co(H2O)6]2+ to be an active site of HER in the present work.

Covalent versus noncovalent attachments of [FeFe]‑hydrogenase models onto carbon nanotubes for aqueous hydrogen evolution reaction

In an effort to develop the biomimetic chemistry of [FeFe]‑hydrogenases for catalytic hydrogen evolution reaction (HER) in aqueous environment, we herein report the integrations of diiron dithiolate complexes into carbon nanotubes (CNTs) through three different strategies and compare the electrochemical HER performances of the as-resulted 2Fe2S/CNT hybrids in neutral aqueous medium. That is, three new diiron dithiolate complexes [{(μ-SCH2)2N(C6H4CH2C(O)R)}Fe2(CO)6] (R = N-oxylphthalimide (1), NHCH2pyrene (2), and NHCH2Ph (3)) were prepared and could be further grafted covalently to CNTs via an amide bond (this 2Fe2S/CNT hybrid is labeled as H1) as well as immobilized noncovalently to CNTs via π-π stacking interaction (H2) or via simple physisorption (H3). Meanwhile, the molecular structures of 1–3 are determined by elemental analysis and spectroscopic as well as crystallographic techniques, whereas the structures and morphologies of H1-H3 are characterized by various spectroscopies and scanning electronic microscopy. Further, the electrocatalytic HER activity trend of H1 > H2 ≈ H3 is observed in 0.1 M phosphate buffer solution (pH = 7) through different electrochemical measurements, whereas the degradation processes of H1-H3 lead to their electrocatalytic deactivation in the long-term electrolysis as proposed by post operando analysis. Thus, this work is significant to extend the potential application of carbon electrode materials engineered with diiron molecular complexes as heterogeneous HER electrocatalysts for water splitting to hydrogen.

Bioinspired Diiron Complex with Proton Shuttling and Redox-Active Ligand for Electrocatalytic Hydrogen Evolution.

A μ-oxo diiron complex, featuring the pyridine-2,6-dicarboxamide-based thiazoline-derived redox-active ligand, H2L (H2L = N2,N6-bis(4,5-dihydrothiazol-2-yl)pyridine-2,6-dicarboxamide), was synthesized and thoroughly characterized. [FeIII-(μ-O)-FeIII] showed electrocatalytic hydrogen evolution reaction activity in the presence of different organic acids of varying pKa values in dimethylformamide. Through electrochemical analysis, we found that [FeIII-(μ-O)-FeIII] is a precatalyst that undergoes concerted two-electron reduction to generate an active catalyst. Fourier transform infrared spectrum of reduced species and density functional theory (DFT) investigation indicate that the active catalyst contains a bridged hydroxo unit which serves as a local proton source for the Fe(III) hydride intermediate to release H2. We propose that in this active catalyst, the thiazolinium moiety acts as a proton-transferring group. Additionally, under sufficiently strong acidic conditions, bridged oxygen gets protonated before two-electron reduction. In the presence of exogenous acids of varying strengths, it displays electro-assisted catalytic response at a distinct applied potential. Stepwise electron-transfer and protonation reactions on the metal center and the ligand were studied through DFT to understand the thermodynamically favorable pathways. An ECEC or EECC mechanism is proposed depending on the acid strength and applied potential.

Co/CoO nanoparticles loaded on multi-walled carbon Nanotubes@Covalent organic frameworks for electrocatalytic hydrogen evolution

Producing hydrogen by electrolyzing water has received increased attention. Nevertheless, a major challenge remains in the search for high performance hydrogen evolution reaction (HER) electrocatalysts. In this work, multi-walled carbon nanotubes (MWCNTs) capped by TpPa covalent organic framework (TpPa-COF) react with cobalt nitrate hexahydrate (Co(NO3)2·6H2O) to form a novel ternary one-body complex (MWCNTs@TpPa-COF@Co/CoO). Wherein, TpPa-COF is constructed from 2,4,6-Triformylphloroglucinol (Tp) and p-phenylenediamine (Pa) as structural units. This COF is relatively inexpensive, provides more coordination sites for metal loading, and is particularly stable in acidic and basic media. The results show that the composite material has high electrocatalytic HER activity in a potassium hydroxide (KOH) condition with an overpotential value of 28.8 mV and a Tafel slope of 69.07 mV dec−1 at a current density of 10 mA cm−2. Meanwhile, the MWCNTs@TpPa-COF@Co/CoO showed excellent stability after 2000 cycles in alkaline media. The characterization demonstrated that the material provided low resistance during the charge transfer process, which resulted in improved electrochemical performance. In addition, the COF loaded with cobalt nanoparticles provided more active sites for the reaction. Thus, the synthesized MWCNTs@TpPa-COF@Co/CoO emerges turns out to be a Pt-free, stable and efficient HER electrocatalyst, holding significant promise for practical applications.

Investigation of palladium-doped 2D g-C3N5 materials for enhanced electrocatalytic activity towards hydrogen evolution reaction

Hydrogen is widely recognized as an extremely environmentally friendly energy source due to its unique characteristics, notably its high energy density and complete absence of carbon emissions. The electrocatalytic technique is the most efficient for hydrogen production among various techniques. Designing an electrocatalyst that is highly electrochemically efficient, catalytically active, stable, cost-effective, and environmentally durable, especially in harsh conditions (highly acidic and basic), is still challenging. Herein, the new set of compositions of Pd-doped g-C3N5 was successfully synthesized by a simple carbonization method using a mixture of 3-amino-1,2,4-triazole (3AT) and PdCl2. Among these materials, nanosheets synthesized g-C3N5/Pd-1 % with the optimized ratio demonstrate the most impressive electrocatalytic performance for the hydrogen evolution reaction (HER). This material exhibits a very low onset overpotential of approximately -10 mV vs. RHE, the smallest Tafel slope value of 47.6 mV dec‑1, and achieves a current density of 10 mV/cm−2 at an overpotential of 69 mV vs. RHE. The catalytic materials also offer very good stability and durability for electrocatalytic HER activity. The upgraded catalytic activity towards HER of g-C3N5/Pd-1 % results from the improved and easy charge transfer and optimized synergism between Pd and g-C3N5. Hence, the synthesized g-C3N5/Pd-1 % materials could potentially serve as a substitute for Pt-based electrocatalysts in practical hydrogen production for the hydrogen evolution reaction (HER).

Ratio design of bimetallic Pd‐Rh nanoparticles on MoS2 nanosheets: Excellent electrocatalysts for hydrogen evolution reaction

The decrease in noble metal content presents an efficient approach to attain commercial, effective, and durable electrocatalysts for the hydrogen evolution reaction (HER) at a low fabrication cost. Nonetheless, achieving a proper balance between bimetallic loading ratios and HER performance remains challenging. In this study, a simple and environmentally friendly sonochemical method is employed to successfully synthesize bimetallic palladium–rhodium nanoparticles (Pd‐Rh) with varying ratios, confined within molybdenum disulfide (MoS2) nanosheets. Bimetallic Pd‐Rh/MoS2 composite with different ratios of Pd:Rh is synthesized by adjusting the feed ratio of Pd and Rh precursors (1:4, 1:1, and 4:1). The HER electrocatalytic activity of the bimetallic Pd1‐Rh1/MoS2 composite exhibits the lowest overpotential and a superior Tafel slope, closely rivaling the electrocatalytic activity of the commercial 20 wt% Pt/C. Furthermore, the bimetallic Pd1‐Rh1/MoS2 composite exhibits remarkable stability and durability, with almost negligible performance decay after 2000 cycles. These outstanding HER electrocatalytic properties of the bimetallic composite result from a higher number of active sites, a significantly larger electrochemically active surface area, reduced charge‐transfer resistance, and a larger double‐layer capacitance. These factors collectively facilitate faster adsorption and desorption of hydron on the surface of electrocatalyst.

One-step hydrothermal synthesis of nanowire-like W/Mo-Ni3S2/NF electrocatalysts for highly efficient hydrogen evolution reactions

The design of nanostructures and the adjustment of components are very important to improve the performance of hydrogen evolution electrocatalysts. In this paper, Ni, W and Mo trimetallic catalysts are studied from the aspects of morphology, structure and electronic transfer, and a better combination of hydrogen reaction efficiency is obtained. The W/Mo co-doped nickel sulfide electrocatalyst was synthesized on Ni foam by one-step hydrothermal method. As anticipated, the individual incorporation of either tungsten (W) or molybdenum (Mo) into the electrocatalyst did not yield satisfactory enhancements in hydrogen evolution reaction (HER) performance. However, when both W and Mo were co-doped onto the electrocatalyst, a significant improvement in catalyst material performance was observed. Hence, the coexistence of W and Mo is the key to improve HER electrocatalytic activity. In 1 M KOH solution, the W/Mo-Ni3S2/NF electrocatalyst exhibited exceptional HER activity with an overpotential of only 136 mV at a current density of 10 mA·cm−2 and demonstrated excellent cycle stability exceeding 20 hours. In this paper, the strategy of bimental co-doping composite is adopted to adjust the structure of nickel sulfide, which provides reference value for the design of reasonable and efficient HER electrocatalyst.