Electrocatalytic Hydrogen Evolution Research Articles

Electrocatalytic Hydrogen Evolution Reaction of Cobalt Triaryl Corrole Bearing Nitro Group

The use of non–precious metals for electrocatalytic hydrogen reaction (HER) is particularly important for energy conservation and environmental protection. In this work, three new cobalt corroles containing o−, m−, and p−nitrobenzyl (1, 2, 3) at the meso 10−position of the corrole macrocycle were synthesized, and their electrocatalytic hydrogen evolution reaction in organic and neutral aqueous systems was also investigated. The results show that these three cobalt corroles have significant catalytic HER activity in both systems, and the catalytic efficiency follows 1 > 3 > 2, which indicates that the position of the nitro group can affect the catalytic property of the complexes. In the organic phase, when using trifluoroacetic acid or p−toluenesulfonic acid as the proton source, the electrocatalytic HER may undergo an EECC (E: electron transfer, C: proton coupling) pathway. In a neutral aqueous system, the HER turnover frequency value of 1 is up to 137.4 h−1 at 938 mV overpotential.

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.

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.

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.

Phase-controlled synthesis of starch-derived Mo2C–MoC/C heterostructure catalyst for electrocatalytic hydrogen evolution reaction

The electronic structure of molybdenum carbide closely resembles that of Pt, making it a promising candidate material for replacing noble metal catalysts. However, the primary challenge is the controlled and eco-friendly synthesis of molybdenum carbide. Herein, we developed a sustainable and controlled method for synthesizing a heterostructure catalyst for the electrocatalytic hydrogen evolution reaction (HER) using starch as the raw material. Through a hydrothermal redox reaction and subsequent temperature-programmed treatment under an inert atmosphere, the hexagonal Mo2C-cubic MoC heterostructure nanoparticles were dispersed on a carbon matrix. Our investigation into the synthesis process extensively covered the growth of MoO2 nanocrystals and hydrochar during the hydrothermal redox reaction, as well as the phase evolution during the subsequent temperature-programmed treatment. Electrochemical assessments demonstrated the catalyst's remarkable efficiency for the hydrogen evolution reaction across both acidic and alkaline media, achieving a current density of 10 mA/cm2 with an overpotential of 139.4 mV in 1 M KOH solution and 160.7 mV in 0.5 M H2SO4 solution. Combining a series of electrochemical characterizations and applying the distribution of relaxation times (DRT) analysis to operando electrochemical impedance spectroscopy (EIS) data, the superior kinetic performance of the Mo2C–MoC/C was demonstrated, outperforming that of single-phase molybdenum carbide. Furthermore, the catalyst has demonstrated remarkable stability even at high current densities in both acidic and alkaline electrolytes, underscoring its potential as a cathode catalyst in both alkaline water electrolyzers and proton exchange membrane (PEM) electrolyzers.

Crystal-Phase-Selective Etching of Heterophase Au Nanostructures.

Selective oxidative etching is one of the most effective ways to prepare hollow nanostructures and nanocrystals with specific exposed facets. The mechanism of selective etching in noble metal nanostructures mainly relies on the different reactivity of metal components and the distinct surface energy of multimetallic nanostructures. Recently, phase engineering of nanomaterials (PEN) offers new opportunities for the preparation of unique heterostructures, including heterophase nanostructures. However, the synthesis of hollow multimetallic nanostructures based on crystal-phase-selective etching has been rarely studied. Here, a crystal-phase-selective etching method is reported to selectively etch the unconventional 4H and 2H phases in the heterophase Au nanostructures. Due to the coating of Pt-based alloy and the crystal-phase-selective etching of 4H-Au in 4H/face-centered cubic (fcc) Au nanowires, the well-defined ladder-like Au@PtAg nanoframes are prepared. In addition, the 2H-Au in the fcc-2H-fcc Au nanorods and 2H/fcc Au nanosheets can also be selectively etched using the same method. As a proof-of-concept application, the ladder-like Au@PtAg nanoframes are used for the electrocatalytic hydrogen evolution reaction (HER) in acidic media, showing excellent performance that is comparable to the commercial Pt/C catalyst.

Layered -bismuthene maximizes the active sites in Bi2Te3 towards electrocatalytic hydrogen evolution reactions

The need of sustainable energy sources drives the development of efficient hydrogen evolution reaction (HER) catalysts, inspiring innovative approaches to boost catalytic performance. Here, we introduce a method harnessing the unique properties of layered bismuthene to enhance the active sites of Bi2Te3. Through comprehensive characterization using XRD, FTIR, SEM, TEM, XPS, and Raman analysis, we elucidate the structural and morphological features of the synthesized material. Electrochemical assessments by employing cyclic voltammetry, linear sweep voltammetry, electrochemical impedance spectroscopy, and chronoamperometry techniques reveal the superior electrocatalytic performance of bismuthene incorporated Bi2Te3 composite, characterized by reduced overpotential (119 mV vs RHE at −10 mA/cm2) and Tafel slope (95.4 mV/dec). These findings underscore the efficacy of a few layered bismuthene in enhancing hydrogen production activity, particularly in alkaline environments, for sustainable water splitting processes. Our work presents findings that contribute to the development of catalysts which are scalable, eco-friendly and promise to revolutionize renewable energy technologies, paving the way for a cleaner and more accessible era of hydrogen fuel.

Electrocatalytic hydrogen evolution coupled with dye hydrogenation reactions for sustainable wastewater treatment using transition-metal (Fe, Co, Ni, Cu) nanoparticles with ZnO nanowire supports

A water electrolysis coupled with chemical reduction strategy is proposed to realize sustainable wastewater treatment. Correspondingly, a series of transition-metal (e.g., iron, cobalt, nickel and copper) nanoparticles anchored on zinc oxide nanowire array (ZnO NA) with bifunctional catalytic activity for hydrogen evolution reaction together with dye hydrogenation reaction (HER/DHR) are developed, while their catalytic activity are comparatively investigated at the same time. This renewable strategy with environmental and economic benefits exhibits high-efficiency treatment capability towards various dye wastewaters. For example, a typical system based on nickel nanoparticles with ZnO NA supports, which exhibits higher catalytic activity towards the HER/DHR than those of other three counterparts under the same conditions, can transform waste 4-nitrophenol into valuable 4-aminophenol with an apparent rate constant of 36.95 × 10-3 min−1 and a conversion rate of 98.32 %, thereby achieving dye decolorization and resource regeneration simultaneously. Its efficiency is significantly superior to that of chemical method dependent on traditional reducing agents and commercial nickel materials, demonstrating its stronger competitiveness. It is mainly benefited from the interface synergistic effect of nickel nanoparticles and zinc oxide nanowires. This novel system is expected to replace conventional sewage remediation technologies for efficient, inexpensive, and eco-friendly dye degradation, and thus is very important for energy and environmental sustainability.

Metal atom doping with GeC: Tuning electronic, magnetic and electrocatalytic hydrogen evolution

The crystal structure stability, electronic and magnetic properties, field emission, and catalytic properties of the metal-doped GeC systems are investigated by the first principles. The Ef (formation energy) in the range of −5.713 to −14.240 eV indicates that the metal-doped GeC systems have energy stability. The Al-, Cr-, Fe-, Co-, Cu-, and Zn-doped GeC systems exhibit metallic properties, but the Ti-, V-, Mn-, and Ni-doped GeC systems retain semiconductor properties. Notably, the V-, Cr-, Mn-, Fe-, Co-, Cu-, and Zn-doped GeC systems exhibit magnetism due to doping effects. In addition, the Ti-, V-, Cr-, Mn-, Fe-, and Co-doped GeC systems have field emission properties relative to the intrinsic GeC due to the decrease of work function. Importantly, the low over-potential indicates that the doping systems have strong electro-catalytic hydrogen production ability. Therefore, the metal-doped GeC has potential applications in spintronic, field emission devices, and electro-catalytic hydrogen production.

α-Fe2O3/, Co3O4/, and CoFe2O4/MWCNTs/Ionic Liquid Nanocomposites as High-Performance Electrocatalysts for the Electrocatalytic Hydrogen Evolution Reaction in a Neutral Medium.

Transition metal oxides are a great alternative to less expensive hydrogen evolution reaction (HER) catalysts. However, the lack of conductivity of these materials requires a conductor material to support them and improve the activity toward HER. On the other hand, carbon paste electrodes result in a versatile and cheap electrode with good activity and conductivity in electrocatalytic hydrogen production, especially when the carbonaceous material is agglomerated with ionic liquids. In the present work, an electrode composed of multi-walled carbon nanotubes (MWCNTs) and cobalt ferrite oxide (CoFe2O4) was prepared. These compounds were included on an electrode agglomerated with the ionic liquid N-octylpyridinium hexafluorophosphate (IL) to obtain the modified CoFe2O4/MWCNTs/IL nanocomposite electrode. To evaluate the behavior of each metal of the bimetallic oxide, this compound was compared to the behavior of MWCNTs/IL where a single monometallic iron or cobalt oxides were included (i.e., α-Fe2O3/MWCNTs/IL and Co3O4/MWCNTs/IL). The synthesis of the oxides has been characterized by X-ray diffraction (XRD), RAMAN spectroscopy, and field emission scanning electronic microscopy (FE-SEM), corroborating the nanometric character and the structure of the compounds. The CoFe2O4/MWCNTs/IL nanocomposite system presents excellent electrocatalytic activity toward HER with an onset potential of -270 mV vs. RHE, evidencing an increase in activity compared to monometallic oxides and exhibiting onset potentials of -530 mV and -540 mV for α-Fe2O3/MWCNTs/IL and Co3O4/MWCNTs/IL, respectively. Finally, the system studied presents excellent stability during the 5 h of electrolysis, producing 132 μmol cm-2 h-1 of hydrogen gas.

Two-dimensional metallic CoTe2 flakes for electrocatalytic hydrogen evolution

Two-dimensional metallic CoTe2 flakes for electrocatalytic hydrogen evolution

Ir Nanoparticles Supported on Oxygen-Deficient Vanadium Oxides Prepared by a Polyoxovanadate Precursor for Enhanced Electrocatalytic Hydrogen Evolution.

Developing highly active electrocatalysts is crucial for the application of electrocatalytic water splitting. In this study, we prepared vanadium oxide-graphene carbon nanocomposites (VxOy/C) with abundant defects using a carbon- and oxygen-rich hexavanadate derivative Na2[V6O7{(OCH2)3CCH3}4] as a precursor without the addition of an extra carbon source. Subsequently, the VxOy/C was used as a catalyst support to load a small amount of Ir, forming the Ir/VxOy/C nanoelectrocatalyst. This catalyst exhibited low hydrogen evolution overpotentials of only 18.90 and 13.46 mV at a working current density of 10 mA cm-2 in 1.0 M KOH and 0.5 M H2SO4 electrolyte systems, outperforming the commercial Pt/C catalysts. Additionally, the catalyst showed excellent chemical stability and long-term durability. This work provides a new strategy for the design and synthesis of highly active electrocatalysts for water splitting.

Anchoring Pt nanoparticle onto monolayer VS2 nanosheets boost efficient acidic hydrogen evolution

The electrocatalytic hydrogen evolution reaction (HER) is a key technology for hydrogen production and plays a significant role in advancing sustainable energy conversion. This study successfully anchored platinum (Pt) nanoparticles onto monolayer VS2 nanosheets via a colloidal chemistry method to enhance their HER performance under acidic conditions. The monolayer VS2 nanosheets provide a stable substrate, with their large surface area and high in-plane electrical conductivity effectively enhancing the interfacial electron transfer and electrochemical contact of the Pt nanoparticles. The Pt/VS2 composite material significantly reduces the energy barrier required for HER and enhances electrochemical activity, while also lowering the cost of the catalyst. At a current density of 10 mA cm−2, the composite material with Pt nanoparticles anchored onto VS2 nanosheets achieved an overpotential of just 26 mV and exhibited a high mass activity of 23.7 A/mgPt. Density functional theory (DFT) calculations and experimental analyses further elucidated the critical role of interfacial electronic effects and sulfur vacancy modulation in enhancing catalytic efficiency. These findings highlight the potential of interface engineering to control electronic structure and sulfur vacancies, significantly enhancing the hydrogen production efficiency and cost-effectiveness of Pt-based catalysts even at low Pt loadings under acidic conditions.

Lattice-Disordered High-Entropy Alloy Engineered by Thermal Dezincification for Improved Catalytic Hydrogen Evolution Reaction.

A disordered crystal structure is an asymmetrical atomic lattice resulting from the missing atoms (vacancies) or the lattice misarrangement in a solid-state material. It has been widely proven to improve the electrocatalytic hydrogen evolution reaction (HER) process. In the present work, due to the special physical properties (the low evaporation temperature of below 900 °C), Zn is utilized as a sacrificial component to create senary PtIrNiCoFeZn high-entropy alloy (HEA) with highly disordered lattices. The structure of the lattice-disordered PtIrNiCoFeZn HEA is characterized by the thermal diffusion scattering (TDS) in TEM. Density functional theory (DFT) calculations reveal that lattice disorder not only accelerates both the Volmer step and Tafel step during the HER process but also optimizes the intensity and distribution of projected density of states (PDOS) near the Fermi energy after the H2O and H adsorption. Anomalously high alkaline HER activity and stability are proven by experimental measurements. This work introduces a novel approach to preparing irregular lattices offering highly efficient HEA and a TDS characterization method to reveal the disordered lattice in materials. It provides a new route towards exploring and developing the catalytic activities of materials with asymmetrically disordered lattices. This article is protected by copyright. All rights reserved.

Preparation of Ni3S2 Electrocatalyst from Different Sulfur Sources and its Performance in Electrocatalytic Hydrogen Evolution Reaction

Preparation of Ni3S2 Electrocatalyst from Different Sulfur Sources and its Performance in Electrocatalytic Hydrogen Evolution Reaction

Advanced Development of In situ Characterization Technique for Electrocatalytic Hydrogen Evolution Reaction

AbstractHydrogen evolution reaction (HER) from water splitting using renewable energy provides a promising solution to the global energy crisis and environmental problems. However, the lack of in‐depth understanding of the reaction mechanism and clear identification of the catalytic active site has hindered the further development of low‐cost, high‐performance, and long‐life efficient electrocatalysts. Through in situ characterization techniques, the activity and stability of catalysts can be monitored in real‐time, track the structural evolution of catalytic reaction intermediates, and obtain a deep understanding of catalytic reaction mechanism, so as to feedback and guide the development and utilization of the catalyst. In this review, advanced development of in situ characterization techniques in electrocatalytic HER in recent years is summarized. In situ spectroscopy can be used to track the behavior of reaction intermediates such as adsorption, desorption, and structural evolution at the molecular level to reveal the electrocatalytic HER mechanism. The imaging techniques can be used to observe the evolution of material structure during HER in situ, which provides valuable information for the understanding of visualization of catalytic hydrogen evolution at atomic level. This review contributes to theadvanced development of in situ characterization technique for electrocatalytic HER.

In-situ growth of MoSe2 on N-doped Ti3C2Tx for electrocatalytic hydrogen evolution in alkaline media

Abstract Serious environmental contamination and the energy crisis have heightened public desire for new renewable energy sources. Because of its high energy content and non-polluting qualities, hydrogen energy has emerged as a viable alternative to fossil fuels. Currently, high-purity hydrogen is typically produced through water electrolysis. The sensible use of electrocatalysts in this process can significantly minimize power usage in the electrolysis of water, which is of great significance to industrial production. However, the electrocatalyst that is inexpensive, has abundant reserves and performs well has yet to be discovered, severely restricting the promotion and application of hydrogen energy. In this paper, a MoSe2/N-doped Ti3C2TX heterostructure with notable electrocatalytic hydrogen evolution activity in an alkaline environment was fabricated via nitrogen doping and in-situ growth of molybdenum selenide. When the current density is 10 mA·cm-2, its overpotential and Tafel slope are 321.87 mV and 139.97 mV·dec-1, respectively. This work serves as a valuable experimental reference for the development of non-noble metal electrocatalysts based on two-dimensional materials.

Strong interaction-induced in situ-reconstructed Ag3 triangle as a real active unit for enhanced electrocatalytic hydrogen evolution

Strong interaction-induced in situ-reconstructed Ag3 triangle as a real active unit for enhanced electrocatalytic hydrogen evolution

MoSx nanowire networks derived from [Mo3S13]2− clusters for efficient electrocatalytic hydrogen evolution

MoSx nanowire networks derived from [Mo3S13]2− clusters for efficient electrocatalytic hydrogen evolution

Directional Growth and Density Modulation of Single-Atom Platinum for Efficient Electrocatalytic Hydrogen Evolution.

Dispersion of single atoms (SAs) in the host is important for optimizing catalytic activity. Herein, we propose a novel strategy to tune oxygen vacancies in CeO2-X directionally anchoring the single atom platinum (PtSA), which is uniformly dispersed on the rGO. The catalyst's performance for the hydrogen evolution reaction (HER) can be enhanced by controlling different densities of CeO2-X in rGO. The PtSA performs best optimally densified and loaded on homogeneous and moderately densified CeO2-X/rGO (PtSA-M-CeO2-X/rGO). It exhibited high activity in HER with an overpotential of 25 mV at 0.5 M H2SO4 and 33 mV at 1 KOH than that of almost reported electrocatalysts. Furthermore, it exhibited stability for 90 hours at -100 mA cm-2 in 1 KOH and -150 mA cm-2 in 0.5 M H2SO4 conditions, respectively. Through comprehensive experiments and theoretical calculations, the suitable dispersion density of PtSA on the defects of CeO2-X with more active sites gives the potential for practical applications. This research paves the way for developing single-atom catalysts with exceptional catalytic activity and stability, holding promise in advanced green energy conversion through defects engineering.