Electrocatalysts For Hydrogen Evolution Reaction Research Articles

A strongly coupled 1T'-ReSe2@2H-MoSe2 van der Waals heterostructure for efficient electrocatalytic hydrogen evolution at high current densities.

Developing efficient and durable non-noble metal electrocatalysts for high current-density hydrogen evolution reactions (HER) is a pressing requirement for commercial industrial electrolyzers. In this study, a vertical 1T'-ReSe2@2H-MoSe2 van der Waals heterostructure was developed through interface engineering to enhance the advantages of each component and expose numerous active sites. Experimental investigations and density functional theorycalculations demonstrate significant electronic coupling at the interface between 1T'-ReSe2 and 2H-MoSe2, with suitable Gibbs free energy for hydrogen adsorption. The 1T'-ReSe2@2H-MoSe2 heterostructure catalyst achieves high current density HER with low overpotentials of 191 mV to generate up to 800 mA/cm2 in 0.5 M H2SO4, outperforming commercial 5% Pt/C catalysts. Moreover, this catalyst exhibits rapid reaction kinetics and long-term durability, illustrating a successful approach to designing efficient heterostructure electrocatalysts for hydrogen production through interface engineering.

Constructing 2D PtSe2/PtCo Heterojunctions by Partial Selenization for Enhanced Hydrogen Evolution

AbstractThe rational design and fabrication of 2D heterojuctions are proven a promising strategy for boosting the performance of electrocatalysts. Although 2D platinum diselenide (PtSe2) exhibits catalytic activity for hydrogen evolution reaction (HER), the catalytic performance is still unsatisfactory due to its inert basal plane, wide bandgap, and poor electron transfer ability. Herein, a new strategy is reported to construct PtSe2/PtCo heterojunctions by partial selenization of PtCo alloy for high‐efficiency HER electrocatalyst, which exhibits a low overpotential of 38 mV at the current density of 10 mA cm−2, a small Tafel slope of 22 mV dec−1, and a superior stability over 24 h and 1000 cycles. The outstanding HER activity of the catalyst arises from the strong electronic interactions between PtSe2 and PtCo in the heterojunctions, which induce electron transferring from PtSe2 to PtCo and the d‐band center down shifting, and thus optimize the H* adsorption/desorption. This work provides a novel strategy for constructing highly efficient heterostructure electrocatalysts, which facilitates the applications of hydrogen energy conversion.

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.

D-Band Center Engineering of Nickel Nanoparticles Accelerates Water Dissociation for Hydrogen Evolution in Neutral NaCl Solution.

While Pt is highly efficient for hydrogen evolution reaction (HER), its widespread use is limited by scarcity and high cost. Herein, a vertically aligned electrocatalyst is present comprising Ni3S2 nanotube arrays (NTAs) and Ni nanoparticles (NPs) (Ni3S2/Ni NTAs) for neutral HER. In a neutral 4 wt.% NaCl solution (pH = 7), the Ni3S2/Ni NTAs achieves a current density of 100mA cm-2 at a low overpotential of 540mV, outperforming both Ni3S2 NTAs and Ni NTAs and even the commercial Pt plate. The hollow tubular structure offers ample mass transfer channels, and strong electronic interaction between Ni3S2 and Ni is observed. Theoretical studies reveal that the lowered d-band center (ɛd) of Ni 3d orbital significantly reduces the activation energy for H2O dissociation and facilitates the movement of an H atom in H2O away from OH to form a transition state, consequently promoting H2 evolution. When Ni3S2/Ni NTAs is used as the cathode in a two-electrode diaphragm-free electrolyzer with a RuSnTi anode, efficient H2 production and energy-saving Cl2 evolution are achieved. This work highlights the potential of uniquely structured electrocatalysts for HER in neutral NaCl solutions.

S−S Bond Strategy at Sulfide Heterointerface: Reversing Charge Transfer and Constructing Hydrogen Spillover for Boosted Hydrogen Evolution

AbstractDeveloping efficient electrocatalyst in sulfides for hydrogen evolution reaction (HER) still poses challenges due to the lack of understanding the role of sulfide heterointerface. Here, we report a sulfide heterostructure RuSx/NbS2, which is composed of 3R‐type NbS2 loaded by amorphous RuSx nanoparticles with S−S bonds formed at the interface. As HER electrocatalyst, the RuSx/NbS2 shows remarkable low overpotential of 38 mV to drive a current density of 10 mA cm−2 in acid, and also low Tafel slope of 51.05 mV dec−1. The intrinsic activity of RuSx/NbS2 is much higher than that of Ru/NbS2 reference as well as the commercial Pt/C. Both experiments and theoretical calculations unveil a reversed charge transfer at the interface from NbS2 to RuSx that driven by the formation of S−S bonds, resulting in electron‐rich Ru configuration for strong hydrogen adsorption. Meanwhile, electronic redistribution induced by the sulfide heterostructure facilitates hydrogen spillover (HSo) effect in this system, leading to accelerated hydrogen desorption at the basal plane of NbS2. This study provides an effective S−S bond strategy in sulfide heterostructure to synergistically modulate the charge transfer and adsorption thermodynamics, which is very valuable for the development of efficient electrocatalysts in practical applications.

Highly Active and Durable Nanostructured Nickel-Molybdenum Coatings as Hydrogen Electrocatalysts via Solution Precursor Plasma Spraying.

The increasing demand for green hydrogen is driving the development of efficient and durable electrocatalysts for the hydrogen evolution reaction (HER). Nickel-molybdenum (NiMo) alloys are among the best HER electrocatalysts in alkaline electrolytes, and here we report a scalable solution precursor plasma spraying (SPPS) process to produce the highly active Ni4Mo electrocatalysts directly onto metallic substrates. The NiMo coating coated onto inexpensive Ni mesh revealed an excellent HER performance with an overpotential of only 26 mV at -10 mA cm-2 with a Tafel slope of 55 mV dec-1. Excellent operational stability with minimum changes in overpotential were also observed even after extensive 60 hour high-current stability test. In addition, we investigate the influence of different substrates over the catalytic performance and operational stability. We also proposed that a slow, but consistent, dissolution of Mo is the primary degradation mechanism of NiMo-based coatings. This unique SPPS approach enables the scalable production of exceptional NiMo electrocatalysts with remarkable activity and durability, positioning them as ideal cathode materials for practical applications in alkaline water electrolysers.

In-situ synthesis nano PtRuW/WC HER catalyst for acid hydrogen evolution by microwave method

Abstract One of the primary challenges in electrocatalysis for the hydrogen evolution reaction (HER) lies in the development of highly efficient catalysts suitable in acidic environments. Tungsten carbide-based materials have long been proposed as potential substitutes for Pt due to their “Pt-like” electronic properties in the HER process. However, tungsten carbide still falls short of the performance exhibited by commercial precious-metal catalysts. Herein, PtRuW/WC was prepared by a microwave heating method and acted as a HER electrocatalyst. The microwave method not only enhances the diffraction peaks of the substrate tungsten carbide, but also facilitates the growth of metal ions at specific sites. The PtRuW/WC catalyst demonstrates outstanding performance in acidic HER, characterized by a minimal overpotential of 40.7 mV at 10 mA/cm2 (η10). Furthermore, it exhibits exceptional stability in acidic solutions, showing no substantial degradation during 20 h at 1000 mA/cm2. The catalyst-assembled PEM electrolytic water electrode further proves that PtRuW/WC has excellent electrolytic water performance and makes some efforts for the development of commercial PEM electrolytic water.

Iron phosphide nanoparticles anchored on 3D nitrogen-doped graphene as an efficient electrocatalysts for hydrogen evolution reaction in alkaline media

Electrocatalysts play a crucial role in hydrogen evolution reaction (HER), facilitating a clean and sustainable generation of hydrogen energy. To promote the HER process, it is imperative to employ highly efficient, stable, and cost-effective electrocatalysts. This research focuses on the design of iron phosphide nanoparticles anchored onto a porous three-dimensional nitrogen-doped graphene (FeP@3DNG). The porous framework of 3DNG serves a multifaceted purpose: it prevents the aggregation of FeP nanoparticles during phosphidation, safeguards the FeP electrocatalyst from oxidation during the HER, and simultaneously enhances electrical conductivity and stability. Notably, the FeP@3DNG nanocomposite demonstrated the efficient activity and highest HER activity with an overpotential of 76 mV to achieve 10 mA cm−2 and a small Tafel slope of 40.2 mV dec−1 as well as good long-term durability for 20 h in 1.0 M KOH solution. The high performance of the FeP@3DNG nanocomposite can be primarily corresponded to the synergistic effects of the highly active of FeP nanoparticles and advantages of porous three-dimensional graphene with excellent electrocatalytic activity, high specific surface area, and chemical stability, thus, resulting in the improvement the overall electrocatalytic activity.

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.

Nitrogen-doped carbon nanosheet confined PtNi alloy for efficient acidic electrocatalytic hydrogen evolution reaction

Low intrinsic electrocatalytic activity and inferior conductivity limit the application of Ni/NC in acidic electrocatalytic hydrogen evolution reaction (HER). Herein, we prepared nitrogen-doped carbon nanosheet confined PtNi alloy electrocatalysts (PtNi/NC-10) using PtCl62− electrostatic adsorption coupling melamine pyrolysis nitriding strategy. PtNi alloying was confirmed by the crystallinity decrease and lattice expansion of Ni/NC. The alloying and confinement effect of Metal-Organic Frameworks (MOFs) suppresses the oxidation and agglomeration of metal nanoparticles during pyrolysis, thus significantly reducing particle size, increasing specific surface area, and promoting the exposure of active sites. The strong electronic interaction between Pt and Ni optimizeds the surface charge distribution, enhancing the adsorption of H species on electron-rich Pt sites, thereby improving reaction kinetics. In addition, PtNi alloying improves the conductivity of the material, accelerating charge transfer and proton transport. Consequently, the prepared PtNi/NC-10 exhibits superior HER performance than Ni/NC in 0.5 M H2SO4 solution, even comparable to commercial 20 wt% Pt/C, with the overpotentials of 35 mV at 0.01 A cm−2. Furthermore, the electrocatalysts assembled PtNi/NC-10-CP‖RuO2-TFF proton exchange membrane (PEM) electrolyzer only requires 2.32 V cell voltage to achieve 1 A cm−2, presenting practical application prospects. Our work provides a novel idea for designing efficient and stable MOFs confined to alloy-based HER electrocatalysts.

Sustainable hydrogen production with synergistic electron transfer enhancement in nickel-based alkaline HER electrocatalyst empowered by graphene oxide

The hydrogen evolution reaction (HER) plays a crucial role in driving forward the transition to a hydrogen-based economy by providing a means to generate pure hydrogen. However, the efficient and cost-effective production of hydrogen via HER faces significant challenges, particularly at the cathode. To address these challenges, we produced a hybrid material – 2D graphene oxide (GO) sheets coated onto nickel sulfide (NiS) microspheres anchored on Ni Foam (GO@NiS/Ni Foam) using a straightforward synthesis technique. Our research highlights the significant influence of the interaction between GO and NiS on the performance of HER, attributed to the enhancement of electron transport at the interface. Furthermore, the GO@NiS/Ni Foam composite exhibits remarkable durability over extended periods, maintaining its superior functionality for up to 40 h of continuous operation. This underscores its potential for practical implementation in efficient water-splitting processes, offering a promising solution to the challenges hindering widespread adoption of hydrogen technology.

NiMOF-Derived MoSe2/NiSe Hollow Nanoflower Structures as Electrocatalysts for Hydrogen Evolution Reaction in Alkaline Medium.

Metal-organic frameworks (MOFs) are crystalline porous materials for storage and energy conversion applications with three-dimensional pore structure, high porosity, and specific surface area, which are widely utilized in electrocatalysis. Herein, MoSe2/NiSe composites were synthesized by selenization reaction using NiMOF as the precursor. The composites were hollow nanoflower structures with a synergistic effect between MoSe2 and NiSe to promote rapid electron transfer, which exhibited good hydrogen evolution reaction performance in an alkaline medium. At a current density of 10 mA/cm2, the HER overpotential reaches 80 mV, the Tafel slope is 33.86 mV/dec, and the material has good stability, with polarization curves remaining essentially unchanged after 3000 cycles. These results indicate that the method has a promising application in the preparation of efficient and sustainable catalysts for hydrogen production in alkaline medium.

Facile synthesis of nitrogen-containing multiwalled carbon nanotubes as a worth metal-free electrocatalyst for hydrogen evolution reaction and semicarbazide oxidation

Studies of metal-free carbon nanostructures prove effective in energy and environmental applications due to their molecular tunability and vast chemical space. Herein, we synthesize nitrogen-containing multi-walled carbon nanotubes (N-MWCNTs) via. acid-catalysed incorporation of 3, 4-diaminopyridine into multi-walled carbon nanotubes (MWCNTs), and demonstrating their efficacy in electrocatalytic hydrogen evolution reaction (HER) and semicarbazide (SCB) oxidation for energy and environmental waste management, respectively. Successful synthesis is further confirmed by analysis techniques, i.e. Fourier transform infrared (FTIR) spectral analysis shows the diminishing OH frequency around 3250 cm−1 in MWCNTs after functionalization and the formation of an OC–NH bond in N-MWCNTs at 1710 cm−1. X-ray diffraction (XRD) confirms the incorporation of N-species, while Raman spectroscopic analysis indicates an increase in the ID/IG ratio MWCNTs (∼1) to N-MWCNTs (∼1.25), suggesting more defective sites in the N-MWCNTs nanocomposite. X-ray photoelectron spectroscopy (XPS) reveals peaks at 399.38, 400.49, and 402.05 eV, attributed to pyridinic-N, aromatic amide-N, and protonated amine groups, respectively. N₂ adsorption-desorption studies shows a high Brunauer-Emmett-Teller (BET) surface area for N-MWCNTs (119.22 m2/g) compared to MWCNTs (74.94 m2/g). Linear sweep voltammetry (LSV) profiles demonstrate enhanced activity of N-MWCNTs for both HER and SCB oxidation at an ultralow potential of E = −0.55 V vs RHE at 10 mA/cm2, with a lower Tafel slope of 108 mV.dec−1. Moreover, the electrochemical sensing studies indicates on N-MWCNTs were demonstrating an efficient electron transfer to SCB with the lower detection limit of 0.004 μmol. This work provides carbon-based metal-free electrocatalysts for energy harvesting and environmental management.

Application of Hydrogen Spillover to Enhance Alkaline Hydrogen Evolution Reaction

AbstractAlkaline water splitting has shown great potential for industrial‐scale hydrogen production. However, its broad application is constrained by hydrogen evolution reaction (HER) electrocatalysts, which struggle to achieve optimal current density at low overpotential. The utilization of the hydrogen spillover effect to augment the performance of HER represents a burgeoning area of research. Although previous studies mainly focused on hydrogen spillover in acidic media, the latest studies have shown that hydrogen spillover also exists under alkaline conditions, and its role in improving HER performance cannot be ignored. This review examines the mechanisms of HER under acidic and alkaline conditions, elucidating the distinctive behavior of hydrogen spillover in these environments and its influence on catalytic processes. At the same time hydrogen spillover characterization methods are systematically summarized, these technologies for understanding and control of hydrogen release process provides strong support. Finally, the recent electrocatalysts that enhance the catalytic performance of alkaline HER by hydrogen spillover effect are comprehensively sorted out and summarized. This review not only demonstrate the practical value of hydrogen spillover under alkaline conditions, but also provide new directions for future design and optimization of electrocatalysts.

Using Machine Learning to Forecast the Conductive Substrate-Supported Heteroatom-Doped Metal Compound Electrocatalysts for Hydrogen Evolution Reaction

Using Machine Learning to Forecast the Conductive Substrate-Supported Heteroatom-Doped Metal Compound Electrocatalysts for Hydrogen Evolution Reaction

Rationally Designed Mo/Ru-Based Multi-Site Heterogeneous Electrocatalyst for Accelerated Alkaline Hydrogen Evolution Reaction.

The rational design of multi-site electrocatalysts with three different functions for facile H2O dissociation, H-H coupling, and rapid H2 release is desirable but difficult to achieve. This strategy can accelerate the sluggish kinetics of the hydrogen evolution reaction (HER) under alkaline conditions. To resolve this issue, a Mo/Ru-based catalyst with three different active sites (Ru/Mo2C/MoO2) is rationally designed and its performance in alkaline HER is evaluated. The experimental results and density functional theory calculations revealed that, at the heterogeneous Mo2C/MoO2 interface, the higher valence state of Mo (MoO2) and the lower valence state of Mo (Mo2C) exhibited strong OH- and H-binding energies, respectively, which accelerated H2O dissociation. Moreover, the interfacial Ru possessed an appropriate hydrogen binding energy for H-H coupling and subsequent H2 evolution. Thus, this catalyst significantly accelerated the Volmer step and the Tafel step and, consequently, HER kinetics. This catalyst also demonstrated low overpotentials of 19 and 160mV at current densities of 10 and 1000mA cm-2, respectively, in alkaline media and long-term stability superior to that of most state-of-the-art alkaline HER electrocatalysts. This work provides a rational design principle for advanced multi-site catalytic systems, which can realize multi-electron electrocatalytic reactions.

Multi-interface and rich-defects 1T phase MoS2 combine with FeS anchored on reduced graphene oxide for efficient alkaline hydrogen evolution

Exploring and fabricating noble-metal-free and cost-effective electrocatalysts to minimise the excessive potential required is of great significance for alkaline hydrogen evolution reaction (HER). Herein, we report FeS/1T-MP MoS2@rGO heterostructure with 1T and 2H mixed phase MoS2 (1T-MP MoS2) combining with FeS anchored on reduced graphene oxide (rGO) matrix, which is synthetized by utilizing Anderson polyoxometalate as Fe–Mo precursor by a facile hydrothermal method. The FeS/1T-MP MoS2@rGO heterostructure in the form of interconnected nanosheet arrays with multiple interfaces and rich-defects, which is in favor of the immersion of the electrolyte and exposing more active sites. Benefiting from the synergistic advantages of 1T-MoS2, FeS and rGO, FeS/1T-MP MoS2@rGO heterostructure delivers enhanced conductivity, enlarged electrochemical active surface area, and eventually promote the HER kinetics. As expected, FeS/1T-MP MoS2@rGO heterostructure emerges prominent HER activity with low overpotentials of 102 and 256 mV to achieve current density of 10 and 100 mA cm−2, outperforming vast majority of the advanced 1T MoS2-based alkaline HER electrocatalysts.

Controllable synthesis of Pt-rich shell/Mx core [M = Ni, Fe, Co] metal aerogels as efficient electrocatalysts for hydrogen evolution reaction

Water electrolysis for hydrogen production offers a solution to the fossil fuel crisis, relying heavily on electrocatalysts for the hydrogen evolution reaction (HER). Fortunately, metal aerogels (MAs) with three-dimensional network structures reveal great potential as HER electrocatalysts. However, their simple synthesis and widespread application still present significant challenges. Here, PtNix MAs electrocatalysts, by controlling the Ni/Pt feeding ratio and using NaBH4 reduction, are prepared via a simple one-step method. Notably, PtNi4 MAs with Pt-rich shell/Ni core structure exhibit excellent HER property, showing a low overpotential of 16.3 mV at 10 mA cm−2 and a mass activity density of 2.28 A mgPt-1 at 70 mV. The outstanding HER properties of PtNi4 MAs are ascribed to the synergistic catalytic effect of Pt and Ni, the core–shell structure of the sample, and the abundant three-dimensional network porosity. Density functional theory (DFT) demonstrates that PtNi4 MAs’ core–shell structure have the lowest dissociation energy of H2O and ΔGH* on the catalyst surface. Furthermore, the replacement of non-precious metal (Ni/Fe/Co) does not affect the formation of the Pt-rich shell structure. Opposite the substitution of reducing agent species affects the formation of Pt-rich shell structure. This work can offer valuable insights for the future sustainable energy applications of MAs materials.

Advanced multi-component FeCoCuAlMo intermetallic electrocatalysts for efficient and sustainable hydrogen evolution in alkaline freshwater and seawater

Electrolyzing seawater to produce hydrogen is a promising sustainable energy production technology. The current non-precious metal-based hydrogen evolution reaction (HER) electrocatalysts demonstrate inadequate catalytic activity and poor stability in seawater electrolyte. Therefore, developing stable and efficient non-precious metal-based HER electrocatalysts is a major challenge for achieving sustainable green energy development. This work reports a multi-component intermetallic catalyst FeCoCuAlMo prepared by arc melting and chemical dealloying methods. The electrocatalytic hydrogen evolution performance of catalysts with varying atomic ratios (FeCoCu)20(Al70Mo30)80, (FeCoCu)30(Al70Mo30)70, (FeCoCu)40(Al70Mo30)60, and (FeCoCu)50(Al70Mo30)50 in alkaline seawater and alkaline electrolyte was studied. The findings indicate that these catalysts primarily consist of AlMo3 and (Cu0.35Fe0.35Co0.3)Al, among which the dealloyed (FeCoCu)30(Al70Mo30)70 exhibits excellent catalytic activity with overpotentials of 137.54 and 116.91 mV at a current density of 100 mA/cm2 in alkaline seawater and alkaline electrolyte, respectively, outperforming most catalysts. Additionally, it demonstrated long-term stability in alkaline seawater and alkaline electrolyte for 250 and 400 h without significant decay at overpotentials of 236 mV and 276 mV, respectively. This improved performance can be attributed to the unique structure of the multi-component intermetallic compound, which provides good thermodynamic stability and synergistic effects among its constituents, thereby enhancing HER performance. Within this multi-component intermetallic compound, AlMo3 particles serve as the primary conductive medium to accelerate electron transfer, while (Cu0.35Fe0.35Co0.3)Al serves as the main active site, resulting in a stable structure that provides the catalyst with high catalytic activity and good stability. Thus, the (FeCoCu)30(Al70Mo30)70 electrocatalyst is a promising candidate for seawater electrolysis aimed at hydrogen production.

Evaluating the Hydrogen Evolution Reaction Activity of Colloidally Prepared PtSe2 and PtTe2 Catalysts in an Alkaline Medium.

The hydrogen evolution reaction (HER) in alkaline electrolytes using transition metal dichalcogenides is a research area that is not tapped into. Alkaline HER ( ) is harder to achieve relative to acidic HER ( ), this is attributed to the additional water dissociation step that occurs in basic HER to generate H+ ions. In fact, for most catalysts, their HER activity decreases tremendously when the electrolyte is changed from acidic to basic conditions. Platinum dichalcogenides, PtX2 (X=S, Se, Te), are an interesting member of transition metal dichalcogenides (TMDs) as these show an immense hybridization of the Pt d orbitals and chalcogen p orbitals because of closely correlated orbital energies. The trend in electronic properties of these materials changes drastically as the chalcogen is changed, with PtS2 reported to exhibit semi-conductor properties, PtSe2 is semi-metallic or semi-conductive, depending on the number of layers, while PtTe2 is metallic. The effect of varying the chalcogen atom on the HER activity of Pt dichalcogenides will be studied. Pt dichalcogenides have previously been prepared by direct high-temperature chalcogen deposition of Pt substrate and evaluated as electrocatalysts for HER in H2SO4. The previously employed synthesis procedures for PtX2 limit these compounds' mass production and post-synthesis treatment. In this study, we demonstrated, for the first time the preparation of PtSe2 and PtTe2 by colloidal synthesis. Colloidal synthesis offers the possibility of large-scale synthesis of materials and affords the employment of the colloids at various concentrations in ink formulation. The electrochemical HER results acquired in 1 M KOH indicate that PtTe2 has a superior HER catalytic activity to PtSe2. A potential of 108 mV for PtTe2 and 161 mV for PtSe2 is required to produce a current density of -10 mA cm-2 from these catalysts. PtTe2 has a low Tafel slope of 79 mVdec-1, indicating faster HER kinetics on PtTe2. Nonetheless, the stability of these catalysts in an alkaline medium needs to be improved to render them excellent HER electrocatalysts.