Electrocatalytic Hydrogen Evolution Research Articles

Accelerating H* desorption of hollow Mo2C nanoreactor via in-situ grown carbon dots for electrocatalytic hydrogen evolution

Molybdenum carbide (Mo2C) is a promising non-noble metal electrocatalyst with electronic structures similar to Pt for hydrogen evolution reaction (HER). However, strong H* adsorption at the Mo sites hinders the improvement of HER performance. Here, we synthesized monodisperse hollow Mo2C nanoreactors, in which the carbon dots (CD) were in situ formed onto the surface of Mo2C through carburization reactions. According to finite element simulation and analysis, the CD@Mo2C possesses better mesoscale diffusion properties than Mo2C alone. The optimized CD@Mo2C nanoreactor demonstrates superior HER performance in alkaline electrolyte with a low overpotential of 57 mV at 10 mA cm−2, which is better than most Mo2C-based electrocatalysts. Moreover, CD@Mo2C exhibits excellent electrochemical stability during 240 h, confirmed by operando Raman and X-ray diffraction (XRD). Density functional theory (DFT) calculations show that carbon dots cause the d-band center of CD@Mo2C to shift away from Fermi level, promoting water dissociation and the desorption of H*. This study provides a reasonable strategy towards high-activity Mo-based HER eletrocatalysts by modulating the strength of Mo–H bonds.

Dewetting of Pt Nanoparticles Boosts Electrocatalytic Hydrogen Evolution Due to Electronic Metal‐Support Interaction

AbstractSolid‐state dewetting is the heat‐induced agglomeration of thin metal films into defined nanoparticles (NPs). Dewetted Pt nanoparticles are investigated on F‐doped SnO2 (FTO) substrates as model binder‐free electrodes for the hydrogen evolution reaction (HER). Dewetting of Pt films into particles exposes the FTO substrate and the metal/support (Pt‐FTO) contact line. Despite the decrease in Pt electrochemical surface area (ECSA) upon dewetting, dewetted NPs show a >3‐fold increase in ECSA‐normalized HER activity compared to as‐deposited nanocrystalline Pt films. Electrodes designed with dewetted Pt NPs of different sizes show that the HER activity does not only correlate with the ECSA but also increases with increasing the Pt‐FTO contact line length. The smaller the NPs, the larger the Pt‐FTO contact line, and the higher the activity. This effect is ascribed to electronic metal‐support interaction (EMSI), due to electron transfer from FTO to Pt. It is proposed that EMSI effects alter the electronic structure of Pt sites near the Pt‐FTO contact line, facilitating the H2 evolution kinetics. When NPs are a few nm‐sized, a large mass fraction of Pt is affected by EMSI, resulting in a further increase of HER activity compared to NPs ≥10 nm despite the lower ECSA.

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 a 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/cm2, respectively, and a good long-term stability for at least 24 h at 500 mA/cm2.

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.

Bimetallic Ni and Pt single atoms anchored on nitrogen–phosphorus doped porous carbon fibers to achieve significant electrocatalytic hydrogen evolution

The commercial application of water electrolysis for hydrogen production requires the development of low precious metal catalysts with a high crustal abundance. One feasible strategy is to utilize bimetallic catalysts composed of both transition and precious metals. In this study, a novel N/P-doped Ni/Pt bimetallic catalyst is developed (NiPt@C-NP, 3.68 % Ni, 0.2 % Pt) using polyacrylonitrile fibers as an inexpensive carbon source for catalyst support. Due to strong anchoring from the N and P heteroatoms, the nickel and platinum species are mono-atomically dispersed throughout the catalyst. Under acidic conditions, NiPt@C-NP exhibits a hydrogen evolution overpotential of 89 mV (10 mA cm−2), whereas an unsupported platinum catalyst gives an overpotential of 302 mV. The mass activity of Pt in NiPt@C-NP reaches 36.17 A mgPt−1, which is 33 times higher than 20 % Pt/C (1.07 A mgPt−1). Density functional theory (DFT) calculations reveal that synergistic interactions between Ni and Pt significantly increase the density of state near the Fermi level of NiPt@C-NP, resulting in a reduced bandgap and an enhanced charge transfer capability. Furthermore, the Gibbs free energy at the Pt and Ni sites is − 0.25 and − 0.63 eV, respectively, indicating fast reaction kinetics.

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

Self-reconstructed ZIF-L/Co(OH)2 heterointerface modulates electronic structure of Ru and boosts electrocatalytic hydrogen evolution

Understanding the self-reconstruction behavior and activity modulation mechanism of MOFs in alkaline electrocatalysis is important for developing efficient Ru-based catalysts. As Co-based MOFs, leaf-shaped zeolitic imidazolate framework (ZIF-L) crystals can be partially self-reconstructed to Co(OH)2 by in situ alkaline electrochemical methods. In this regard, two models of ZIF@Ru/NF and Co(OH)2-ZIF@Ru/NF were fabricated, and calculated by DFT. The results showed that the Co(OH)2-ZIF heterointerface generated by self-reconstruction effectively modulated the chemical and electronic environment of Ru, leading to enhanced HER performance. Therefore, Co(OH)2-ZIF@Ru/NF was in situ grown on nickel foam (NF), using ZIF@Ru/NF as a precursor. After LSV activation, the leaf-shaped ZIF-L transformed into finely fragmented nanosheets of Co(OH)2. As anticipated, the Co(OH)2-ZIF@Ru/NF catalyst demonstrated superior electrocatalytic performance compared to numerous reported counterparts, exhibiting an overpotential of 22 mV at a current density of 10 mA cm−2 and a Tafel slope of 16.9 mV dec−1. This study presents a viable method for the preparation of HER electrocatalysts using electrochemical in situ self-reconstruction.

Space confined growth of RuO2/Ru carbon nanorods for highly efficient electrocatalytic hydrogen evolution

Exploring efficient and robust electrocatalysts with low cost for hydrogen evolution reaction (HER) is critical for practical application of electrochemical water splitting. Ru-based platinum group electrocatalysts shows great potential in HER, however, Ru suffer from sluggish kinetics of water dissociation for electrochemical reduction of water to hydrogen in alkaline environments. Here, oxygen atoms are introduced into Ru by simple secondary heat treatment to form Ru–O–C bonds to weak the strength of Ru–H bond. The overpotential of the catalyst is only 19 mV at 10 mA cm−2 and the stability is greatly improved. Theoretical calculations reveal that the Ru–O–C structure formed in RuO2 facilitates the dissociation of H–OH, which is the rate-determining step in alkaline electrolytes, leading to significant improvement in HER activity.

Ginkgo Leaf‐Derived Carbon Supports for the Immobilization of Iron/Iron Phosphide Nanospheres for Electrocatalytic Hydrogen Evolution (Small 21/2024)

Ginkgo Leaf‐Derived Carbon Supports for the Immobilization of Iron/Iron Phosphide Nanospheres for Electrocatalytic Hydrogen Evolution (Small 21/2024)

Laser-thermal reduction synthesis of high-entropy alloys towards high-performance pH universal hydrogen evolution reaction

Owing to their multi-elemental compositions and unique high-entropy mixing states, high-entropy alloy (HEA) nanoparticles (NPs) displaying tunable activities and enhanced stabilities thus have become a rapidly growing area of research in recent years. However, the integration of multiple elements into HEA NPs at the nanoscale remains a formidable challenge, especially when it comes to the precise control of particle size, elemental composition and content. Herein, a simple and universal high-energy laser assisted reduction approach is presented, which achieves the preparation of HEA NPs with a wide range of multi-component, controllable particle sizes and constitution on different substrates within seconds. Laser on carbon nanofibers induced momentary high-temperature annealing (>2000 ​K and ramping/cooling rates > 105 ​K ​s−1) to successfully decorate HEA NPs up to twenty elements with excellent compatibility for large-scale synthesis (20.0 ​× ​20.0 ​cm2 of carbon cloth). The IrPdPtRhRu exhibit robust electrocatalytic hydrogen evolution reaction (HER) activities and low overpotentials of 16, 28, and 12 ​mV at a current density of 10 ​mA ​cm−2 in alkaline (1.0 ​M KOH), alkaline simulated seawater (1.0 ​M KOH ​+ ​0.5 ​M NaCl), and acidic (0.5 ​M ​H2SO4) electrolytes, respectively, and excellent stability (7 days and >2000 cycles) at the alkaline HER.

First Application of Non‐Metallic A2B Type Silicon Corrole Complexes in Electrocatalytic Hydrogen Evolution

AbstractIn this study, we have successfully synthesized two non‐metallic‐based silicon corrole complexes (F10C−Si, F10C−CN−Si) and used them as HER electrocatalysts for the first time. Electrochemical studies indicate the electrocatalytic HER may go via EE‐CEEC (E: electron transfer step, C: chemical step) pathway. Notably, it can be seen that the introduction of electron‐withdrawing cyano group on the meso‐phenyl of the corrole macrocycle may enhance the catalytic activity of silicon corrole complexes. In DMF with TsOH as the proton source, F10C−CN−Si exhibits a turnover frequency (TOF) of 331.48 s−1 and a high catalytic efficiency (C.E) of 1.29. Furthermore, the catalytic prowess of the silicon corrole complexes extends to neutral aqueous solution, with F10C−CN−Si achieving a TOF of 52.72 h−1 at an overpotential of 1188 mV. This study extends the application of non‐metallic‐based silicon corrole molecular catalysts in the electrocatalytic HER field.

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.

Polyoxometalate and ammonium polyphosphate induced bimetallic tungsten-based phosphides for electrocatalytic hydrogen production

Tungsten-based phosphide has gained significant traction in the field of electrocatalytic hydrogen evolution on account of its platinum-like characteristics, cost-effectiveness and exceptional electrical conductivity. In this work, bimetallic phosphide (WP/WCoP2@C) was prepared for hydrogen evolution reaction (HER) via high-temperature annealing and in situ phosphating procedure using the green phosphorus source ammonium polyphosphate (APP) without no toxic substances generated. WP/WCoP2@C exhibits satisfactory catalytic hydrogen evolution activity, with the overpotentials in acidic and alkaline environments of 151 and 138 mV, respectively, at current density reaching 10 mV cm−2. Moreover, WP/WCoP2@C shows favorable stability in the acid-base electrolytes for 36 h. This work provides experimental ideas for the green clean synthesis of tungsten-based phosphides for electrochemical small molecules transformation for sustainable energy generation.

Atomically Dispersed Platinum on Conjugated Polymers with Tailored Cation‐π Interactions and Microstructures for Hydrogen Evolution Electrocatalysis

AbstractDeveloping high‐performance platinum (Pt) single atom catalyst with maximum metal‐atom‐utilization efficiency is of significance for water electrolysis, which demonstrates enormous potentials toward hydrogen evolution reaction (HER). In addition to stably immobilizing Pt single atoms on a support material, it is highly desired to elaborately tailor their coordination environments for achieving optimized HER performance. In this work, a general strategy is reported to develop advanced catalysts with Pt single atoms immobilized on conjugated polymers, where their coordination environments and HER activities can be readily tailored by adjusting the cation‐π interactions formed between the Pt single atoms and conjugated polymers. For the proof‐of‐concept study, polypyrrole (PPy), polyfuran (PFu), and polythiophene (PTh) with analogous molecular structures are investigated, where the N, O, and S heteroatoms in PPy, PFu, and PTh can affect their π domains and induce different cation‐π interactions. Experimental and theoretical studies both suggest that the HER performance of the resulting catalysts follows the trend of Pt1‐PTh < Pt1‐PFu < Pt1‐PPy, which shows a correlation with their cation‐π interactions. Moreover, by utilizing the microstructure‐tailorable property of conjugated polymers, PPy aerogel with enhanced specific surface area are prepared to support Pt single atoms, achieving substantial HER performance improvement.

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.

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.

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.

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.