High-performance Hydrogen Evolution Reaction Catalysts Research Articles

Boosting Hydrogen Evolution Reaction Activity of Amorphous Molybdenum Sulfide Under High Currents Via Preferential Electron Filling Induced by Tungsten Doping.

The lack of highly efficient, durable, and cost‐effective electrocatalysts for the hydrogen evolution reaction (HER) working at high current densities poses a significant challenge for the large‐scale implementation of hydrogen production from renewable energy. Herein, amorphous molybdenum tungsten sulfide/nitrogen‐doped reduced graphene oxide nanocomposites (a‐MoWSx/N‐RGO) are synthesized by plasma treatment for use as high‐performance HER catalysts. By adjusting the plasma treatment duration and chemical composition, an optimal a‐MoWSx/N‐RGO catalyst is obtained, which exhibits a low overpotential of 348 mV at a current density of 1000 mA cm−2 and almost no decay after 24 h of working at this current density, outperforming commercial platinum/carbon (Pt/C) and previously reported heteroatom‐doped MoS2‐based catalysts. Based on density functional theory (DFT) calculations, it is found that with a reasonable tungsten doping level, the catalytic active site (2S2 − ) shows excellent catalytic performance working at high current densities because extra electrons preferentially fill at 2S2 − . The introduction of tungsten tends to lower the electronic structure energy, resulting in a closer‐to‐zero positive ΔGH∗. Excessive tungsten introduction, however, can lead to structural damage and a worse HER performance under high current densities. The work provides a route towards rationally designing high‐performance catalysts for the HER at industrial‐level currents using earth‐abundant elements.

Edge terminated and interlayer expanded pristine MoS2 nanostructures with 1T on 2H phase, for enhanced hydrogen evolution reaction

Pristine molybdenum disulfide (MoS 2 ) nanostructures with 1T on 2H phase have been prepared by tuning the growth time in hydrothermal synthesis. The optimized sample has an expanded interlayer and it exhibits striking kinetic metrics with an onset potential of - 0.13 V, Tafel slope of 49 mV/decade, and an exchange current density of 3.98 × 10 −3 mA, performing best among the pristine MoS 2 based hydrogen evolution reaction (HER) catalysts reported so far. The edge terminated structure, together with the expanded interlayer, is believed to modify the electronic structure to enhance the conductivity of the compound. The Mott-Schottky analysis of the optimized sample indicated a decrease in band bending and an enhancement in the charge transfer. The promising HER response obtained with sufficiently low growth time and growth temperature for the pristine MoS 2 nanostructures suggests a potential way to design high-performance HER catalysts based on the compound. • Fabricated edge terminated, interlayer expanded 1T on 2H MoS 2 nanostructures. • 1T phase with HER active (001) plane obtained without the addition of any dopant. • Optimized sample has lower onset potential of −0.13 V and Tafel slope of 49 mV/dec. • High exchange current density of 3.98 × 10 −3 mA for the optimized sample. • Durable HER catalyst with high stability using MoS 2 nanostructures.

Electrospun nano-Ir anchored mesoporous carbon nanofibers for hydrogen evolution reaction

It is essential to develop high-performance hydrogen evolution reaction catalysts. Reducing the amount of precious metals is an effective approach to replace Pt-based catalyst. Here, an electrocatalyst of metallic iridium anchored on mesoporous carbon nanofibers (Ir- m CNFs) is reported. After optimized the nanostructure (pore-forming agent content) of Ir- m CNFs, at the current density of 10 mA cm −2 , the overpotential reaches 28 and 39 mV in alkaline and acid medium. Moreover, the content of Ir in this catalyst is just around 6 wt%. In conclusion, this paper reports an effective precious metal based HER catalysts with a lower amount of rare metals.

Facile Synthesis of 1T-Phase MoS2 Nanosheets on N-Doped Carbon Nanotubes towards Highly Efficient Hydrogen Evolution.

1T-phase molybdenum disulfide is supposed to be one of the non-precious metal-based electrocatalysts for the hydrogen evolution reaction with the highest potential. Herein, 1T-MoS2 nanosheets were anchored on N-doped carbon nanotubes by a simple hydrothermal process with the assistance of urea promotion transition of the 1T phase. Based on the 1T-MoS2 nanosheets anchored on the N-doped carbon nanotubes structures, 1T-MoS2 nanosheets can be said to have highly exposed active sites from edges and the basal plane, and the dopant N in carbon nanotubes can promote electron transfer between N-doped carbon nanotubes and 1T-MoS2 nanosheets. With the synergistic effects of this structure, the excellent 1T-MoS2/ N-doped carbon nanotubes catalyst has a small overpotential of 150 mV at 10 mA cm−2, a relatively low Tafel slope of 63 mV dec−1, and superior stability. This work proposes a new strategy to design high-performance hydrogen evolution reaction catalysts.

Ru nanoparticles supported on partially reduced TiO2 as highly efficient catalyst for hydrogen evolution

The development of low-cost yet highly efficient catalysts for hydrogen evolution reaction (HER) is crucial for large-scale clean and sustainable hydrogen production from water splitting. Tuning the interfacial structure of catalyst has emerged as an effective strategy to optimize the intrinsic catalytic activity. In this study, we demonstrated the deposition of Ru nanoparticles by freshly prepared strong reductive Ti(III) oxide, resulting in Ru/reduced TiO 2 interface with oxygen vacancies. The as-prepared Ru/r-TiO 2 exhibited a superior HER performance over commercial Pt/C in alkaline media, with only a small overpotential of 15 mV required to deliver the benchmark current density of 10 mA cm −2 and a high turnover frequency of 8.74 s −1 achieved at an overpotential of 100 mV. Density functional theory calculation indicates that high electrocatalytic activity of Ru/r-TiO 2 is originated from the promotion of water dissociation and weakening OH adsorption by reduced TiO 2 , which facilitate the conversion of water to H 2 . This work provides an efficient strategy for the design of high-performance HER catalysts. • Reduced TiO 2 -supported Ru nanocatalyst with negatively charged Ru and oxygen vacancies was prepared. • Ru/r-TiO 2 exhibited a superior hydrogen evolution activity in alkaline media. • Only an overpotential of 15 mV is need to deliver a benchmark current density of 10 mA cm −2 . • High HER activity was attributed to the synergy of promoting water dissociation and weakening OH* adsorption.

Magnetocatalysis: The Interplay between the Magnetic Field and Electrocatalysis

Magnetocatalysis: The Interplay between the Magnetic Field and Electrocatalysis

Cr-Doped CoP Nanorod Arrays as High-Performance Hydrogen Evolution Reaction Catalysts at High Current Density.

Developing highly efficient, low-cost electrocatalysts with long-time stability at high current density working conditions for hydrogen evolution reaction (HER) remains a great challenge for the large-scale commercialization of hydrogen production from water electrolysis. Herein, the Cr-doped CoP nanorod arrays on carbon cloth (Cr-CoP-NR/CC) is reported as high performance HER catalysts with overpotentials of 38 and 209mV at the HER current densities of 10 and 500 mA cm-2 , respectively, outperforming the performance of the commercial Pt/C at high current density. And its HER performance shows almost no loss after 20 h working at 500 mA cm-2 . The high performance is attributed to the Cr doping, which optimizes the hydrogen binding energy of CoP and prevents its oxidation. The nanorod array structure helps the escaping of the generated hydrogen gas, which is suitable for working at high current density. The obtained Cr-CoP-NR/CC catalyst shows the potential to replace the costly Pt-based HER catalysts in the water electrolyzer.

VSe2 quantum dots with high-density active edges for flexible efficient hydrogen evolution reaction

Two-dimensional (2D) metallic transition metal dichalcogenides (TMDCs) with large specific surface areas and high conductivities are promising catalysts for electrocatalytic hydrogen production. The highly active edges of the 2D metallic TMDCs are the desirable catalytic sites for the hydrogen evolution reaction (HER). Herein, the vanadium diselenide (VSe2) quantum dots with high-density edge sites are prepared by tip sonication of the self-detached VSe2 nanosheets. The spontaneously released VSe2 nanosheets, without chemical-involved transfer, offer a noncontaminated catalyst for HER. Compared to the VSe2 nanosheets, VSe2 quantum dots with a high density of active edges present a significant enhancement of the electrocatalytic performance. The reduced overpotential and transfer resistance indicate the lower Gibbs free energy and faster faradic process of the VSe2 quantum dots for HER. The active edge sites of VSe2 quantum dots show improved catalytic properties in thermodynamic and kinetic aspects. The VSe2 quantum dots loaded on a carbon cloth could be used as a flexible electrode for HER. This work provides an effective way to regulate the defects of the 2D TMDCs for high-performance HER catalysts and also offers a catalyst for flexible HER.

Design of 2D Layered Catalyst by Coherent Heteroepitaxial Conversion for Robust Hydrogen Generation

AbstractThe structural engineering of 2D layered materials is emerging as a powerful strategy to design catalysts for high‐performance hydrogen evolution reaction (HER). However, the ultimate test of this technology under typical operating settings lies in the reduced performance and the shortened lifespan of these catalysts. Here, a novel approach is proposed to design efficient and robust HER catalysts through out‐of‐plane deformation of 2D heterojunction using metal‐organic chemical vapor deposition. High‐yield, single‐crystalline WTe2 nanobelts are used as an epitaxial template for their coherent conversion to WS2. During the conversion process, the WTe2/WS2 heterostructure containing both lateral and vertical junctions are achieved by coherent heteroepitaxial stacking despite differences in symmetry. The lattice coherency drives out‐of‐plane deformation of heteroepitaxially grown WS2. The increase in the effective surface area and decrease in the electron‐transfer resistance across the 2D heterojunctions in turn enhances the HER performance as well as the long‐term durability of these electrocatalysts.

Effective Descriptor for Designing High-Performance Catalysts for the Hydrogen Evolution Reaction

Broad application of the hydrogen evolution reaction (HER) for developing clean and sustainable energy depends upon high-performance HER catalysts, which is in dire need of a universal and easily a...

Perpendicularly anchored ReSe2 nanoflakes on reduced graphene oxide support for highly efficient hydrogen evolution reactions

Hydrogen evolution reaction (HER) by water splitting has made a significant contribution to producing large amounts of hydrogen gas as the next generation fuel. Development of highly efficient, economically viable, and electrochemically stable HER electrocatalysts has accordingly become a prerequisite for practical implementation of large scale water electrolysis. Mono/few-layered transition metal dichalcogenide (TMD) based HER-electrocatalysts have recently garnered great interest due to their diverse tunable electrochemical properties. However, they still face intrinsic limitations such as self-aggregation, rare active sites, high electrical resistance, and long-term electrochemical instability. To tackle these challenges, we designed and synthesized a novel electrocatalyst comprising active site-rich rhenium diselenide (ReSe2) nanoflakes perpendicularly anchored on a reduced graphene oxide (rGO) nanosheet support via a facile one-step hydrothermal synthesis. The rGO support provides a growing platform for few-layered ReSe2 nanoflakes while facilitating plentiful exposure of edge/corner sites of ReSe2, highly desirable for maximizing the catalytic activity of ReSe2@rGO. The synthesized ReSe2@rGO exhibits a low overpotential of 145.3 mV at a current density of 10 mA·cm−2 with a Tafel slope of 40.7 mV·dec−1 for the HER process due to the synergistic combination of high surface density of unsaturated coordination sites, remarkably accelerated electron transfer, and enhanced electrochemical stability. This outcome suggests using structurally regulated hybridization of TMDs and graphene as a platform toolkit for developing high performance HER catalysts.

Conversion of bimetallic MOF to Ru-doped Cu electrocatalysts for efficient hydrogen evolution in alkaline media

The rational design and construction of inexpensive and highly active electrocatalysts for hydrogen evolution reaction (HER) is of great importance for water splitting. Herein, we develop a facile approach for preparation of porous carbon-confined Ru-doped Cu nanoparticles (denoted as Ru-Cu@C) by direct pyrolysis of the Ru-exchanged Cu-BTC metal–organic framework. When served as the electrocatalyst for HER, strikingly, the obtained Ru-Cu@C catalyst exhibits an ultralow overpotential (only 20 mV at 10 mA cm−2) with a small Tafel slope of 37 mV dec−1 in alkaline electrolyte. The excellent performance is comparable or even superior to that of commercial Pt/C catalyst. Density functional theory (DFT) calculations confirm that introducing Ru atoms into Cu nanocrystals can significantly alter the desorption of H2 to achieve a close-to-zero hydrogen adsorption energy and thereby boost the HER process. This strategy gives a fresh impetus to explore low-cost and high-performance catalysts for HER in alkaline media.

Recent advances in single metal atom-doped MoS2 as catalysts for hydrogen evolution reaction

The development of low-cost and highly efficient electrocatalysts for hydrogen evolution reaction (HER) is critical to the wide-spread applications of water splitting technology. In recent years, many efforts are devoted to exploring HER catalysts with high activity and stability based on non-precious metals. Benefited from the advantages of two-dimensional (2D) materials with unique physicochemical properties along with the single-atom catalysts with high activity, excellent stability and maximized atom utility efficiency, a new category of catalysts with 2D materials confining single atoms have shown great promises as high-performance HER catalysts. In this review, MoS2, as one of the typical 2D materials, doped with various single metal atoms as HER catalysts are fully discussed, including different synthetic strategies, catalytic performances and mechanisms toward HER as well as the major challenges ahead.

Effects of Ion Energy and Density on the Plasma Etching-Induced Surface Area, Edge Electrical Field, and Multivacancies in MoSe2 Nanosheets for Enhancement of the Hydrogen Evolution Reaction.

Plasma functionalization can increase the efficiency of MoSe2 in the hydrogen evolution reaction (HER) by providing multiple species but the interactions between the plasma and catalyst are not well understood. In this work, the effects of the ion energy and plasma density on the catalytic properties of MoSe2 nanosheets are studied. The through-holes resulting from plasma etching and multi-vacancies induced by plasma-induced damage enhance the HER efficiency as exemplified by a small overpotential of 148 mV at 10 mA cm-2 and Tafel slope of 51.6 mV dec-1 after the plasma treatment using a power of 20 W. The interactions between the plasma and catalyst during etching and vacancies generation are evaluated by plasma simulation. Finite element and first-principles density functional theory calculations are also conducted and the results are consistent with the experimental results, indicating that the improved HER catalytic activity stems from the enhanced electric field and more active sites on the catalyst, and reduced bandgap and adsorption energy arising from the etched through-holes and vacancies, respectively. The results convey new fundamental knowledge about the plasma effects and means to enhance the efficiency of catalysts in water splitting as well insights into the design of high-performance HER catalysts.

Nanoporous Palladium–Silver Surface Alloys as Efficient and pH-Universal Catalysts for the Hydrogen Evolution Reaction

Developing electrocatalysts that are more efficient and robust than platinum for pH-universal hydrogen evolution reaction (HER) is crucial for scalable and sustainable hydrogen production through electrochemical water splitting. Here we report platinum-free bimetallic surface alloys of palladium and silver, which spontaneously form on self-supported three-dimensional nanoporous Pd–Ag–Al electrodes during the selective etching process, as high-performance HER catalysts in both basic and acidic media. As a consequence of Ag weakening moderately the hydrogen bonding energy of nearby surface Pd atoms to improve HER intrinsic activity and interconnective metal skeleton facilitating electron transfer, nanoporous Pd–Ag–Al electrodes exhibit low onset overpotential and ultralow Tafel slopes (∼26 and ∼56 mV dec–1) and overpotentials (∼63 and ∼108 mV) at 200 mA cm–2 in 0.5 M H2SO4 and 1 M KOH electrolytes, respectively, with long-term cycling stability. The catalytic properties make them attractive alternatives to ...

Ultrathin MoSSe alloy nanosheets anchored on carbon nanotubes as advanced catalysts for hydrogen evolution

The activity of transition metal dichalcogenides (TMD) toward hydrogen evolution reaction (HER) derives from the active sites at the edges, but the basal surface still remain catalytic insert. Herein, ultrathin MoSSe alloy nanosheets array on multiwalled carbon nanotubes (MWCNTs) to form a core shell structure via a simple solvothermal process. These three-dimensional (3D) MoSSe hybrids show a high activity in hydrogen evolution reaction (HER) with a small Tafel slope of 38 mV dec−1 and a low overpotential of 102 mV at 10 mA cm−2. In addition, their HER activity remains remarkably stable without significant decay after 100 h polarization. Such superior catalytic HER activity springs from the 3D hierarchical heterostructure, which is abundant of catalytic edge sites, and the alloy effect between S and Se, which will create huge defects and strain to form vacancy sites on the basal plane. This strategy may open a new avenue toward the development of nonprecious high-performance HER catalysts.

Multi-site electrocatalysts for hydrogen evolution in neutral media by destabilization of water molecules

High-performance hydrogen evolution reaction (HER) catalysts are compelling for the conversion of renewable electricity to fuels and feedstocks. The best HER catalysts rely on the use of platinum and show the highest performance in acidic media. Efficient HER catalysts based on inexpensive and Earth-abundant elements that operate in neutral (hence biocompatible) media could enable low-cost direct seawater splitting and the realization of bio-upgraded chemical fuels. In the challenging neutral-pH environment, water splitting is a multistep reaction. Here we present a HER catalyst comprising Ni and CrOx sites doped onto a Cu surface that operates efficiently in neutral media. The Ni and CrOx sites have strong binding energies for hydrogen and hydroxyl groups, respectively, which accelerates water dissociation, whereas the Cu has a weak hydrogen binding energy, promoting hydride coupling. The resulting catalyst exhibits a 48 mV overpotential at a current density of 10 mA cm−2 in a pH 7 buffer electrolyte. These findings suggest design principles for inexpensive, efficient and biocompatible catalytic systems. Integrating electrocatalytic H2 production with biological H2-fed systems for CO2 upgrading requires H2 generation to occur in biocompatible media—typically with neutral pH. Here, the authors design multi-site H2 evolution catalysts that minimize the water dissociation barrier and promote hydride coupling in neutral media.

Poor crystalline MoS2 with highly exposed active sites for the improved hydrogen evolution reaction performance

Poor crystalline MoS2/C hollow nanosphere with highly exposed active sites were rationally designed for the enhanced the hydrogen evolution reaction (HER) performance and long-term durability. Polyoxometalates were used as oxidants to spontaneously initiate the polymerization of pyrrole, and served as Mo sources for synthesizing MoS2 in the following sulfurization, as well as P sources for doping carbon. Solid, hollow, and double-shelled hollow nanoshperes were facilely controlled via improving the annealing temperature, and showing varied HER performance due to the variations in nanostructure, crystallinity, defects, mass transports, etc. It is found that hollow nanospheres annealed at 800 °C exhibited the best HER performance, showing overpotential of 207 mV at 10 mA cm−2, and Tafel slope of 73 mV dec−1, as well as long-term stability for 25 h. Poor crystalline phase with abundant defective sites and highly accessible surface area possessing highly exposed active sites, as well as the synergistic effects between MoS2 and N, P-dual doped mesoporous carbon, contributed to improving the HER performance. Present work proved that the smart manipulation of the crystallinity of MoS2 is an efficient way to prepare high performance HER catalysts, which might be further utilized in photoelectrocatalytic water splitting in comparison to complete amorphous phase.

Ultrafine Co Nanoparticles Encapsulated in Carbon-Nanotubes-Grafted Graphene Sheets as Advanced Electrocatalysts for the Hydrogen Evolution Reaction.

The rational design of an efficient and inexpensive electrocatalyst based on earth-abundant 3d transition metals (TMs) for the hydrogen evolution reaction still remains a significant challenge in the renewable energy area. Herein, a novel and effective approach is developed for synthesizing ultrafine Co nanoparticles encapsulated in nitrogen-doped carbon nanotubes (N-CNTs) grafted onto both sides of reduced graphene oxide (rGO) (Co@N-CNTs@rGO) by direct annealing of GO-wrapped core-shell bimetallic zeolite imidazolate frameworks. Benefiting from the uniform distribution of Co nanoparticles, the in-situ-formed highly graphitic N-CNTs@rGO, the large surface area, and the abundant porosity, the as-fabricated Co@N-CNTs@rGO composites exhibit excellent electrocatalytic hydrogen evolution reaction (HER) activity. As demonstrated in electrochemical measurements, the composites can achieve 10 mA cm-2 at low overpotential with only 108 and 87 mV in 1 m KOH and 0.5 m H2 SO4 , respectively, much better than most of the reported Co-based electrocatalysts over a wide pH range. More importantly, the synthetic strategy is versatile and can be extended to prepare other binary or even ternary TMs@N-CNTs@rGO (e.g., Co-Fe@N-CNTs@rGO and Co-Ni-Cu@N-CNTs@rGO). The strategy developed here may open a new avenue toward the development of nonprecious high-performance HER catalysts.

Efficient Hydrogen Evolution Electrocatalysis Using Cobalt Nanotubes Decorated with Titanium Dioxide Nanodots.

TiO2 Co nanotubes decorated with nanodots (TiO2 NDs/Co NSNTs-CFs) are reported as high-performance earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solution. TiO2 NDs/Co NSNTs can promote water adsorption and optimize the free energy of hydrogen adsorption. More importantly, the absorbed water can be easily activated in the presence of the TiO2 -Co hybrid structure. These advantages will significantly promote HER. TiO2 NDs/Co NSNTs-CFs as electrocatalysts show a high catalytic performance towards HER in alkaline solution. This study will open up a new avenue for designing and fabricating low-cost high-performance HER catalysts.