Electrocatalytic Hydrogen Evolution Reaction Research Articles

Preparation of V2O3 by a short process of ammonium salt reduction and its electrocatalytic properties investigation

Ammonium salt vanadium precipitation is the main method of vanadium metallurgy at home and abroad, but the traditional ammonium precipitation of vanadium can only obtain high valence of V2O5, and the NH3 produced in the calcination process cannot be fully utilized. And the preparation of low-valence vanadium oxide V2O3 is long and costly. Self-reduction of thermal decomposition of nitrogen-containing precipitation products to produce V2O3 is a novel and short process method that can achieve full utilization of ammonia. NaVO3 was used as the vanadium source, choline chloride (C5H14ClNO (ChCl)) was used as the vanadium precipitation reagent, and the vanadium concentration was 30 g/L, n(ChCl)/n(V) = 1.5, the initial pH was 1.5, the temperature was 85°C, the time was 2 h, and the vanadium precipitation efficiency could reach 97.05%. V2O3 with purity of 97.98% can be obtained by calcination at 550°C for 3 h in an argon atmosphere. XRD, FTIR, XPS, SEM-EDS were used to characterize the product, which further proved that the final product was V2O3. The electrocatalytic hydrogen evolution reaction (HER) of V2O3 in acidic media showed high stability after 1000 cyclic voltammetry (CV) cycles, with a low Tafel slope of 88.5 mVdec−1. The electrochemical double layer capacitance (EDLC) was measured by CV at different scan rates, and the EDLC of V2O3 was 1.104 mFcm−2. This study provides a short-flow preparation method for V2O3 and can provide predictions for the application of V2O3 in HER and supercapacitors.

Ruthenium–Nickel Nanoparticles with Unconventional Face‐Centered Cubic Crystal Phase for Highly Active Electrocatalytic Hydrogen Evolution

AbstractRu‐based nanomaterials are promising alternatives to Pt electrocatalysts for green hydrogen energy generation, and crystal phase engineering holds the key to unlocking their catalytic potential to new heights. However, controllable phase regulation on Ru‐alloys remains a formidable challenge, and unraveling the crystal phase‐related electrocatalytic performance is of great significance. Herein, RuNi nanoparticles are successfully synthesized with an unconventional face‐centered cubic (fcc) phase via a facile route. Comprehensive transmission electron microscopy confirmed the structural characteristics of the fcc‐RuNi and electrochemical analyses indicate the impressive electrocatalytic hydrogen evolution reaction of fcc‐RuNi. Notably, the anomalous fcc‐RuNi nanoparticles possess an extraordinarily low overpotential of 16 mV in hydrogen evolution. Density functional theory calculations indicate that these nanoparticles are energetically conducive to intermediate desorption and H2O dissociation. This study enhances comprehension of phase regulation in Ru‐based nanostructures and will propel phase engineering in diverse catalytic applications.

Heterojunction engineering via in-situ electrochemical reconstruction for boosting electrocatalytic biomass upgrading-coupled hydrogen production

Rationally designing and constructing high-performance electrocatalysts is critical for environmental and sustainable electrocatalytic biomass upgrading coupled with hydrogen evolution. Herein, we developed a novel in-situ electrochemical reconstruction strategy to fabricate heterostructured electrocatalysts for efficient biomass upgrading-coupled hydrogen production. Through in-situ anodic and cathodic electrochemical reconstructions, Ni(OH)2-CuO nanorods assembled by nanosheets with abundant low-crystalline Ni(OH)2/crystalline CuO heterojunctions on Cu foam (Ni(OH)2-CuO/CF) and S-doped Ni(OH)2-Cu2O nanofoam formed by cross-linked nanoparticles on CF (Ni(OH)2-Cu2O(S)/CF) were respectively constructed for electrocatalytic 5-hydroxymethylfurfural oxidation reaction (HMFOR) and hydrogen evolution reaction (HER). For the Ni(OH)2-CuO/CF, the overall configuration of nanorods assembled by self-standing nanosheets ensures good conductivity, full exposure of active sites, and fast mass/electron transfer. The abundant Ni(OH)2/CuO heterojunctions provide dual active sites of Ni and Cu to simultaneously adsorb and activate hydroxyl and aldehyde groups in HMF. The electronic interaction between Ni(OH)2 and CuO accelerates the reversible conversion of Ni2+↔Ni3+ to generate more Ni3+ active species and enhances the intrinsic activity of dual active sites to reduce the reaction energy barrier of the rate-determining step. As a result, the Ni(OH)2-CuO/CF shows superior HMFOR performance, with a HMF conversion of 99.3%, a FDCA yield of 98.1%, and stability for 50 cycles in 10 mM HMF+1.0 M KOH medium. Meanwhile, the Ni(OH)2-Cu2O(S)/CF also exhibits remarkable HER activity with an overpotential of only 64.7 mV at 10 mA cm−2 in 1.0 M KOH solution due to its unique structure and composition. When coupling a two-electrode system, the HMFOR-HER system achieves a current density of 10 mA cm−2 at 1.44 V, 221 mV lower than that of the OER-HER system. This work provides an in-situ electrochemical reconstruction strategy for designing advanced heterojunction-rich electrocatalysts for various electrocatalytic applications.

Hydrogen Spillover Effect in Electrocatalysis: Delving into the Mysteries of the Atomic Migration

Hydrogen spillover effect has recently garnered a lot of attention in the field of electrocatalytic hydrogen evolution reactions. A new avenue for understanding the dynamic behavior of atomic migration in which hydrogen atoms moving on a catalyst surface was opened up by the setup of the word “hydrogen spillover.” However, there is currently a dearth of thorough knowledge regarding the hydrogen spillover effect. Currently, the advancement of sophisticated characterization procedures offers progressively useful information to enhance our grasp of the hydrogen spillover effect. The understanding of material fabrication for hydrogen spillover effect has erupted. Considering these factors, we made an effort to review most of the articles published on the hydrogen spillover effect and carefully analyzed the aspect of material fabrication. All of our attention has been directed toward the molecular pathway that leads to improve hydrogen evolution reactions performance. In addition, we have attempted to elucidate the spillover paths through the utilization of DFT calculations. Furthermore, we provide some preliminary research suggestions and highlight the opportunities and obstacles that are still to be confronted in this study area.

Phase-Engineered Dichalcogenides/Fluorine-Free V4C3Tx (T=OH, O) Heterostructures for pH-Universal Hydrogen Evolution Reaction.

This research addresses the pH-dependency limitation in electrocatalytic hydrogen evolution reactions (HER) by creating heterostructures through the chemical bonding between 2D-dichalcogenides and V4C3Tx (T=OH, O) planes. The one-step solvothermal synthesis employed in this study constructs a synergistically interacted 1T phase of, e.g., MoS2 and V4C3Tx MXene, demonstrating an omnidirectional improvement on catalytic stability, active site exposure, surface area enlargement, electrical conductivity, and hence enhancement of water dissociation activities. Despite the notable progress in creating hydrogen production catalysts with ground breaking performances, a significant gap remains in the availability of catalysts capable of functioning effectively under high current densities. The catalyst 1T MoS2@V4C3Tx shows remarkable activities under the current density of 1000mAcm-2, which require overpotentials of 16, 24, and 37mV in 0.5m H2SO4, 1 m KOH, and 0.1 m PBS electrolytes, respectively at 10 mA cm-2, and exhibits excellent HER performance with small overpotentials of 103.16 and 138mV to achieve current densities of 500 and 1000mAcm-2, respectively, with outstanding stability for 1000 cylic voltammetriccycle HER test without degradation in acidic media. Enhanced HER performance has also been observed in other 2D-dichalcogenides/V4C3Tx heterostructures, providing prospects for phase-engineered dichalcogenides/fluorine-free V4C3Tx composites for pH-universal HER.

In-situ observation of hydrogen nanobubbles formation on graphene surface by AFM-SECM

Gas bubble evolution is an important phenomenon in many electrochemical processes and it is highly sensitive to the surface properties. Here we visualize the gas bubble dynamics on the surface of different graphene substrates during hydrogen evolution reaction (HER) using atomic force microscopy combined with scanning electrochemical microscopy. The low overpotential and low surface hydrophobicity of few-layer graphene formed on C-phase SiC causes the uniform distribution of hydrogen nanobubbles, which easily depart from the surface during the reaction. Conversely, the high overpotential and more hydrophobic surface of HOPG induces hydrogen bubbles to linger on the surface for an extended duration, leading to its accumulation and the subsequent formation of microbubbles. This in-situ nanoscale electrochemical mapping of hydrogen bubble dynamics provides new insight into electrocatalytic HER that occurs on non-metal electrodes.

Synthesis of Stable and Efficient Electrocatalysts for Hydrogen Evolution: Hierarchical NiMo-Based Hollow Nanotubes

Large-scale development of low-cost, efficient, and stable powder electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solutions is a key step toward commercial hydrogen production. Herein, a hierarchical NiMo-MoO3-x hollow nanotube (NiMo-MoO3-x-HNT) with bifunctional groups as an efficient HER electrocatalyst was strategically invented using an MoO3 nanorod (MoO3−NR) as the precursor. The synthesis mechanism of the NiMo-MoO3-x-HNT is established based on in-depth investigations using diffraction, spectral, and microscopy results. Experimental results suggest that the NiMo-MoO3-x-HNT exhibits excellent electrocatalytic HER performance in 1 M KOH, with a low overpotential of 26.5 mV@10.0 mA cm-2 and a small Tafel slope of 32.6 mV dec–1. These values are comparable to those of cutting-edge electrocatalysts based on platinum-group metals. Moreover, it exhibits an almost unaffected cyclic stability over 50,000 cycles and robust durability over 98 h. This remarkable performance is attributed to its bifunctional groups and the porous hierarchical hollow nanotubular morphology. In summary, this study proposes a novel, efficient, and cost-effective strategy for the development of noble metal-free, high-performance HER electrocatalysts.

Metal-support interface engineering for stable and enhanced hydrogen evolution reaction

Hydrogen has emerged as a green and sustainable pathway towards achieving global decarbonization and net-zero emissions, intensely driving the need for efficient hydrogen production protocols. Electrocatalytic hydrogen evolution reaction (HER) holds great potential as a scalable, eco-friendly and safe avenue for efficient hydrogen production. However, the large-scale implementation of electrocatalytic HER is substantially challenged by the high-cost and unstable materials that are mainly fabricated from noble metals, e.g., Pt and Pd. Given this challenge, we adopted an interface engineering strategy to immobilize nanoscale Pt particles within the framework of nitrogen-doped CNTs, namely Pt@N-CNTs, where electronic metal-support interaction (EMSI) plays an important role in enabling orbital rehybridization and regulating the charge transfer through the metal-support interface, thereby considerably improving the electrocatalytic activity. With limited content of noble metals, our developed Pt@N-CNTs delivered superior HER performance with an ultralow overpotential of 5.8 mV at 10 mA cm−2 and demonstrated a high mass activity of 12.72 A mgPt−1 at an overpotential of 50 mV as well as excellent stability under harsh acidic conditions. At 500 mA cm−2, Pt@N-CNTs surprisingly exhibited an overpotential of 55.2 mV, outperforming that of commercial 20 wt% Pt/C catalysts (131.5 mV). Importantly, we established a straightforward, scalable, and time-saving microwave reduction strategy, alluding to its promising commercial viability. This work therefore sheds light on the development of high-performance electrocatalysts for hydrogen evolution and water electrolysis.

Tuning the morphology and crystal phase of Ru nanocatalysts for efficient hydrogen evolution

Regulation of crystal phase of Ru nanocatalysts has been identified as an effective approach in regulating the bonding strength of reaction intermediates to Ru and improving the intrinsic activity of Ru-based catalysts during electrocatalytic hydrogen evolution reaction (HER). Here, we reported that the morphology and crystal phase of Ru nanocatalysts could be facilely regulated by halide anions in hydrothermal synthesis. Structural characterization revealed that halogen anions directed the anisotropic growth of hcp Ru, stabilized Ru crystals from aggregation, and increased the abundance of grain boundaries. As a result, The Ru polycrystalline networks exhibited excellent HER activity and durability with a smaller Tafel slope of 21 mV dec−1 and overpotential (η50) of 18 mV. This work sheds light on the shape and phase control of nanocrystals and future design of high-efficient non-Pt electrocatalysts with enhanced HER performance.

Construction of Pt Single-Atom and Cluster/FeOOH Synergistic Active Sites for Efficient Electrocatalytic Hydrogen Evolution Reaction

Construction of Pt Single-Atom and Cluster/FeOOH Synergistic Active Sites for Efficient Electrocatalytic Hydrogen Evolution Reaction

Atomic-level precision engineering: Single-atom catalysts with controlled loading density for efficient hydrogen evolution reaction

An important but challenging task in single-atom catalysis is synthesizing a catalyst with controllable single-atom loading densities and no metal agglomeration. Here, we construct MoS2/rGO supports by a simple hydrothermal method and precisely control single-atom platinum (PtSA) loading density by its targeted growth on MoS2 for electrocatalysis. Using the optimized geometric and electronic structure, PtSA-MoS2/rGO exhibits an ultra-low overpotential of 11 mV at − 10 mA cm−2 in 0.5 M H2SO4 for electrocatalytic hydrogen evolution reaction (HER). First-principles calculations reveal that enhanced density of PtSA on the MoS2 surface favors the reduction of Gibbs free energy of hydrogen adsorption, facilitating the kinetic process of electrocatalytic HER. This work provides a new engineering route to fabricating a series of performance-tunable single-atom catalysts with controllable locations and loading densities.

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).

Vertically Aligned Pt/MXene/Carbon Nanotubes Aerogels for Superior Hydrogen Evolution Reaction

Herein, we propose a one-step directional-freezing strategy to fabricate 3D vertically aligned aerogel (VA) of Ti3C2Tx MXene/carbon nanotubes (MC) decorated with small Pt species (denoted as Pt@MC-VA) as a self-standing electrode for robust electrocatalytic hydrogen evolution reaction (HER) at ampere-level current density. Numerous small Pt nanoclusters and single-atoms species are spontaneously reduced and anchored on the aerogel skeleton, revealing high intrinsic activity. The MXene nanosheets firmly fixed by carbon nanotubes cooperatively construct the porous frameworks, which greatly reinforces the overall mechanical strength and serves as high-speed path for electron transport. Moreover, the 3D self-supported and super-wettable frameworks with vertically aligned and run-through microchannels significantly facilitate the electrolyte infiltration and the immediate removal of gaseous products at high current densities. Based on these combined advantages, the Pt@MC-VA electrode exhibits a significantly improved electrocatalytic activity with overpotentials as low as 208 and 249 mV to reach high current densities up to 500 and 1000 mA cm-2, respectively, and a good long-term stability for at least 24 h at 500 mA cm-2.

Exploration of transition metal atom-doped NiSe2 electrocatalysts for efficient alkaline hydrogen precipitation using first principles screening

Transition metal (TM) doping exhibits great potential in designing high-performance two-dimensional (2D) NiSe2-based catalysts for electrocatalytic hydrogen evolution reaction (HER). 22 TM atom-doped 2D-NiSe2 catalysts are screened, and the effects of TM doping on the thermal stability and HER catalytic activity are investigated by first-principles calculations. Among them, Cu doped 2D-NiSe2 might exhibit remarkable HER properties with the water dissociation energy of 1.03 eV and H adsorption Gibbs free energy of −0.05 eV. Furthermore, we elucidate the reasons behind the different HER activities. These findings suggest new possibilities for the application of Cu doped 2D-NiSe2 for alkaline HER, offering new perspectives for future research.

The electrocatalytic HER activity of MoS2 decorated with adjustable-size ruthenium nanoparticles

MoS2 is a potential electrocatalytic material for its excellent durability and stability. Here, we investigate the electrocatalytic hydrogen evolution reaction performance of MoS2 nanosheets decorated with size-controlled Ru nanoparticles. The MoS2 compounded with 2.46 nm-Ru exhibits the good electrocatalytic performance with overpotential of 53 mV at 10 mA/cm2 in 0.5 M H2SO4 condition. The enhanced electrocatalytic activity of Ru@MoS2 results from accelerated charge migration between the Ru metal and MoS2 semiconductor, as well as the addition of Ru increases the number of active sites on the surface of MoS2. Furthermore, the first-principles calculations demonstrated the ΔGH* of Ru@MoS2 (−0.05 eV) is lower than P–MoS2 (2.04 eV) and the narrowed bandgap facilitates more efficient electron migration. And the theoretical calculations further reveal that the Ru nanoparticles with suitable size at the interface own the ideal ΔGH* by manipulating the D-band center of the Ru.

Electrocatalyst for hydrogen evolution and H2O2 recognition on composite carbon paste electrodes with three new Ag(I) MOFs

Three new Ag(I) metal-organic frameworks (Ag-MOFs) containing bisbenzimidazole-derived ligand, namely, {[Ag2(L)(TP)](H2O)}n (1), {[Ag2(L)(HBTC))(H2O)](CH3CH2OH)(H2O)}n (2) and {[Ag4(L)2(IP)2](CH3CN)3(H2O)16}n (3) (L = bis(1-(pyridin-4-ylmethyl)-benzimidazol-2-yl methyl) ether, TP = Terephthalate, BTC = Benzenetricarboxylate, IP = Isophthalate), have been synthesized by volatilization method and systematic adjustment of solvent and aromatic polyacid co-ligand. Single crystal structural analysis showed that although three Ag-MOFs have a three-dimensional (3D) network backbone structure, their topological structures are different. Electrocatalytic hydrogen evolution reaction (HER) of carbon paste composite electrodes (Ag-MOF-1∼3@CPE) prepared by mixing graphite powder with Ag-MOFs were investigated in 0.5 M H2SO4 electrolyte. The HER measurements show that the overpotential η10293K of Ag-MOF-1∼3@CPE are -634, -533 and -615 mV compared with sCPCE (blank electrode, -966 mV), and the Tafel slope of sCPCE and Ag-MOF-1∼3@CPE were 276, 251, 123 and 220 mV dec−1, respectively. The results prove that Ag-MOF-1∼3@CPE could effectively catalyze and accelerate the HER behavior, with electrocatalytic activity order being Ag-MOF-2@CPE > Ag-MOF-3@CPE > Ag-MOF-1@CPE > sCPE. The highest HER activity of Ag-MOF-2@CPE can be attributed to the fact that Ag-MOF-2 contains coordination water molecule, while the higher activity of Ag-MOF-3@CPE than Ag-MOF-1@CPE is due to steric hindrance. Furthermore, the recognition performance of Ag-MOF-1∼3@CPE for H2O2 was further studied by chronoamperometry in 0.2 M phosphate buffer solution (PBS, pH = 6). The three sensors can detect H2O2 in a linear range from 0.5 μM to 4 mM with sensitivities of 103, 34.5 and 138 μA·mM−1·cm−2, and also revealed long-term stability and good selectivity. Our study provides a new approach for designing efficient, non-precious metal electrochemical catalysts.

Phenoxide coordination to Fe(III) tetraphenylporphyrin: Exploring antibacterial and electrocatalytic HER activity

Herein, we report synthesis, solid and solution state structure as well as properties of three five coordinate (unsubstituted, 4-NO2 substituted and 2,4,6 trinitro substituted) phenoxide axially ligated to Fe(III)-tetraphenyl porphyrins. Spectroscopic characterization revealed high-spin (S = 5/2) nature of the phenoxide bound Fe(III) porphyrins (Fe1 and Fe2). However, the 2,4,6 trinitro substituted phenoxide axially ligated Fe(III) porphyrin (Fe3) demonstrate spin admixed nature (S = 5/2, 3/2) with predominate high spin contribution. (Phenolato)(porphinato)iron(III) complexes merit attention owing to structural analogy with the catalase enzyme. In this study we investigated their antibacterial as well as electrocatalytic hydrogen evolution reaction (HER) activity. Fe1 demonstrate potent antibacterial activity against gram-negative E. coli (MTCC 443) and gram-positive Staphylococcus aureus (MTCC 3160) human pathogenic bacteria. It also produce catalytic current for electrocatalytic HER activities upon gradual addition of PTSA (para-tolunesulphonic acid) as proton source. Compounds Fe2 and Fe3 also produce enhanced catalytic wave which originate possibly from reduction of proton coupled with reduction of –NO2 group.

The Electrochemical Hydrogen Evolution Reaction Based on Helical Chain Stacked 2D Tellurium Nanoflakes

AbstractA crucial factor in advancing the broad utilization of electrocatalytic hydrogen evolution reaction (HER) is the development of efficient catalysts with sufficient active sites. Herein, a hydrothermal approach is utilized to fabricate helical chain stacked two‐dimensional (2D) tellurium (Te) nanoflakes, whose HER performance hasn't been systematically studied yet. It is found that Te nanoflakes transferred on carbon fiber paper (CFP) exhibit impressive HER properties and show a load dependence. The overpotential required for HER is significantly reduced to 279 mV under a load condition of 0.86 mg cm−2 at a current density of 10 mA cm−2. Density functional theory (DFT) calculations are further systematically carried out on Te catalytic sites along the helical chain at [0001] direction with a threefold screw symmetry. It is found that the Gibbs free energy of adsorbed hydrogen atom (ΔGH*) on Te sites is significantly lower than that of molybdenum disulfide (MoS2). Besides, the active sites based on surface atom density calculation reveal that Te provides more adsorption sites than layered MoS2. The decreased adsorption energy and efficient adsorption sites in Te may highlight the promising application of elemental crystal Te in electrocatalytic hydrogen production and pave the way for developing new types of electrocatalysts.

Molten salts etching route driven construction of C@Ni nanoparticles loaded carbon nanosheet as high-performance electrocatalyst for hydrogen evolution reaction

Developing earth-abundant, low-cost, high-efficiency electrocatalysts for hydrogen evolution reaction (HER) by structure design is still a grand challenge. Herein, we fabricated Ni nanoparticles encapsulated by carbon loaded in two-dimensional carbon nanosheets (2D Ni@C@SU) using a molten salt (NaCl)-assisted pyrolysis method. Because of the large specific surface area (262.35 m²/g) and high electrical conductivity, the prepared 2D Ni@C@SU-0.75 electrocatalyst exhibits excellent HER electrocatalytic activity with the overpotential of −105 mV at −10 mA cm−2 and −367 mV at −200 mA cm−2, which is close to the commercial benchmark Pt/C (η200= −339 mV). Besides, the catalyst displays incredible durability in the electrocatalytic HER. This research indicates that the green solid-state synthetic strategy provides a new window for designing new Ni-based composite catalysts for electrocatalytic HER.

Surface-Engineered Twinned PdIr Nanorods for the Electrocatalytic Hydrogen Evolution Reaction

Surface-Engineered Twinned PdIr Nanorods for the Electrocatalytic Hydrogen Evolution Reaction