Efficient Catalyst For Hydrogen Evolution Reaction Research Articles

Uniformly bimetal-decorated holey carbon nanorods derived from metal−organic framework for efficient hydrogen evolution

The hydrogen evolution reaction (HER) as a fundamental process in electrocatalysis plays a significant role in clean energy technologies. For an energy-efficient HER, it demands an effective, durable, and low-cost catalyst to trigger proton reduction with minimal overpotential and fast kinetics. Here, we successfully fabricate a highly efficient HER catalyst of N-C/Co/Mo2C holey nanorods with Co/β-Mo2C nanoparticles uniformly embedded in nitrogen-doped carbon (N-C/Co/Mo2C) by pyrolyzing the molybdate-coordinated zeolitic imidazolate framework (ZIF-67/MoO42−) holey nanorods, which result from the reaction between CoMoO4 and MeIM in a methanol/water/triethylamine mixed solution. The uniform distribution of MoO42− in the ZIF-67/MoO42− enables Co/β-Mo2C nanoparticles to be well-distributed within nitrogen-doped carbon holey nanorods. This synthetic strategy endows the N-C/Co/Mo2C catalyst with uniformly decorated bimetal, thus attaining excellent HER electrocatalytic activities with a small overpotential of 142.0 mV at 10 mA cm−2 and superior stability in 1.0 mol L−1 KOH aqueous solution.

Transformation of Fe-B@Fe into Fe-B@Ni for efficient photocatalytic hydrogen evolution

It is highly desirable to develop efficient and cost-effective composite catalysts to replace noble metal Pt for hydrogen evolution reaction (HER). For an excellent HER catalyst, both the adsorption and desorption of intermediate H atoms on it should be easy. However, except metal platinum, most individual species cannot satisfy this requirement. Fe-B is an active HER catalyst with strong ability to adsorb H atoms. In our previous work, we found that when Fe-B alloy was decorated with metal Fe particles (Fe-B@Fe), the resultant composite displayed a significant synergic effect for HER compared to single Fe-B and Fe. The role of the decorated Fe on Fe-B is to improve H2 desorption. Because the desorption of H2 molecule from Ni is easier than from Fe, we expect Fe-B@Ni to be a more efficient HER catalyst than Fe-B@Fe. Herein, we transform Fe-B@Fe into Fe-B@Ni by a facile displacement reaction. As a proof of concept, the as-prepared Fe-B@Ni catalyst exhibits much higher electrocatalytic and photocatalytic activity for hydrogen production than the pristine Fe-B@Fe. At the current density of −100 mA cm−2, the overpotential of Fe-B@Ni in 1.0 mol L−1 KOH is close to that of 20 wt% Pt/C. The highest apparent quantum yield (AQY) for dye-sensitized photocatalytic hydrogen evolution reaches 51% at 420 nm. The possible mechanisms have been proposed. These findings provide new insights for designing and fabricating new HER composite catalysts for electrocatalytic and photocatalytic hydrogen evolution.

Ultrastable MXene@Pt/SWCNTs' Nanocatalysts for Hydrogen Evolution Reaction

AbstractDeveloping nano‐ or atom‐scale Pt‐based electrocatalysts for hydrogen evolution reaction (HER) is of considerable importance to mitigate the issues associated with low abundance of Pt. Here, a protocol for constructing a hierarchical Pt––MXene–single‐walled carbon nanotubes' (SWCNTs) heterostructure for HER catalysts is presented. In the heterostructure, highly active nano/atom‐scale metallic Pt is immobilized on Ti3C2Tx MXene flakes (MXene@Pt) that are connected with conductive SWCNTs' network. The hierarchical heterostructure is constructed by filtrating a mixed colloidal suspension containing MXene@Pt and SWCNTs. Taking the advantages of the hydrophilicity and reducibility of MXene, the MXene@Pt colloidal suspension is prepared by spontaneously reducing Pt cations into metallic Pt without additional reductants or post‐treatments. The so‐fabricated hierarchical HER catalysts, in the form of membrane, show high stability during 800 h operation, a high volume current density of up to 230 mA cm−3 at −50 mV versus reversible hydrogen electrode (RHE) and a low overpotential of −62 mV versus RHE at the current density of −10 mA cm−2. This solution‐processed strategy offers a simple, efficient, yet scalable approach to construct stable and efficient HER catalysts. Given the properties and the structure–activity relationships of the hierarchical Pt–MXene–SWCNTs' heterostructure, other MXenes probably show greater promise in HER electrocatalysis.

Machine-learning-accelerated screening of hydrogen evolution catalysts in MBenes materials

Machine learning (ML) models combined with density functional theory (DFT) calculations are employed to screen and design hydrogen evolution reaction (HER) catalysts from various bare and single-atom doped MBenes materials. The values of Gibbs free energy of hydrogen adsorption (ΔGH*) are accurately predicted via support vector algorithm only by using simply structural and elemental features. With the analysis of combined descriptors and the feature importance, the Bader charge transfer of surface metal is a key factor to influence HER activity of MBenes. Co/Ni2B2, Pt/Ni2B2, Co2B2, Os/Co2B2 and Mn/Co2B2 are screened from 271 MBenes and MXenes as active catalysts, with the near-zero ΔGH* of 0.089, −0.082, −0.13, −0.087 and −0.044 eV, respectively. Finally, stable Co2B2 and Mn/Co2B2 are considered as the excellent HER catalysts due to |ΔGH*| < 0.15 eV over a wide range of hydrogen coverages (θ from 1/9 to 5/9). The present work suggests that ML models are competitive tools in accelerating the screening of efficient HER catalysts.

Geometric Structure and Electronic Polarization Synergistically Boost Hydrogen Evolution Kinetics in Alkaline Medium.

Efficient electrocatalysts for the hydrogen evolution reaction (HER) are significant for the utilization of hydrogen as a fuel, particularly under alkaline conditions. However, the sluggish kinetics of HER remains a challenge. Here we demonstrate an efficient HER catalyst comprising Ru and AgCl nanoparticles anchored on Ag nanowires (Ru/AgCl@Ag), which delivers a low overpotential of 12 mV at 10 mA cm-2 and a Tafel slope of 38 mV decade-1. A high mass activity of 214 mA mg-1 at an overpotential of 25 mV and a long-term durability in 1.0 M KOH are observed. In combination with computational simulations, we find that the high electronegativity of chlorine in AgCl and d-band electrons from Ru synergistically destabilize the water molecule and modulate H adsorption/desorption on the surface of Ru/AgCl@Ag, respectively. This work opens a promising avenue for the facile design and application of highly active and stable composite electrocatalysts toward water splitting.

Ruthenium anchored on carbon nanotube electrocatalyst for hydrogen production with enhanced Faradaic efficiency

Developing efficient and stable electrocatalysts is crucial for the electrochemical production of pure and clean hydrogen. For practical applications, an economical and facile method of producing catalysts for the hydrogen evolution reaction (HER) is essential. Here, we report ruthenium (Ru) nanoparticles uniformly deposited on multi-walled carbon nanotubes (MWCNTs) as an efficient HER catalyst. The catalyst exhibits the small overpotentials of 13 and 17 mV at a current density of 10 mA cm–2 in 0.5 M aq. H2SO4 and 1.0 M aq. KOH, respectively, surpassing the commercial Pt/C (16 mV and 33 mV). Moreover, the catalyst has excellent stability in both media, showing almost “zeroloss” during cycling. In a real device, the catalyst produces 15.4% more hydrogen per power consumed, and shows a higher Faradaic efficiency (92.28%) than the benchmark Pt/C (85.97%). Density functional theory calculations suggest that Ru–C bonding is the most plausible active site for the HER.

Self-supported phosphorus-doped CoMoO4 rod bundles for efficient hydrogen evolution

Herein, a series of phosphorus-doped CoMoO4 rod bundles electrocatalysts on 3D nickel foams have been successfully synthesized and exploited as efficient hydrogen evolution reaction (HER) electrocatalyst in 1 M KOH. The incorporation of phosphorus into CoMoO4 can significantly promote the HER activity, and the CoMoO4 bundles phosphorized at 350 °C exhibited the optimum activity, which only required low overpotentials of 56 and 148 mV to deliver cathodic current densities of 10 mA cm−2 and 100 mA cm−2, respectively. This electrode also presented considerable long-term electrochemical stability with negligible delay after 30 h operation and 3000 accelerated cyclic voltammetry cycles. Our study provides a superior earth-abundant catalyst for efficient HER in alkaline media, which also suggests that P doping engineering is an effective way to boost the HER activity of transition metal-based oxides.

High Active and Durable Vanadium Sulfide Multilayer Structure Featuring Rich Hole Defects Constructed for Accelerated Hydrogen Evolution Reaction

VS2 nanomaterials with special morphology, exposed edges, defects have studied as an active and inexpensive electrocatalyst for hydrogen evolution reaction (HER). Here, we reported the fabrication of multilayer Waffle structured VS2 featuring rich hole defects (VS2 MLW). This structure shows excellent kinetic metrics for electrocatalytic HER, exhibiting a overpotential of 82 mV at the current density of −10 mA cm−2, a Tafel slope of 61 mV dec−1, and a long-term stability without any current fading. Its HER performance is much better than that of other V-based catalysts, and even comparable to that of commercial Pt/C. Through experimental and theoretical calculation, the outstanding electrocatalytic activity of the VS2 MLW is attributed to its special morphology and electronic structure. The hole defects in this structure provide larger electrochemical active area and more active sites for HER, more importantly, hole defects change the electron structure of catalyst and reduce the free energy of hydrogen adsorption, the optimized free energy consequently leading to the improved inherent catalytic activity of VS2 MLW. This work provides a new concept to design efficient HER catalyst by specific surface area and defect engineering.

Insights into N, P, S multi-doped Mo2C/C composites as highly efficient hydrogen evolution reaction catalysts.

Heteroatom doping has been proved to be an effective strategy to optimize the activity of hydrogen evolution reaction (HER) catalysts. Herein, we report N, P, S multi-doped Mo2C/C composites exhibiting highly efficient HER performance in acidic solution, which are facilely fabricated via annealing of N, P, S-containing MoOx–polyaniline (MoOx–PANI) hybrid precursors. The optimized N, P, S multi-doped Mo2C/C catalyst with a moderate P dopant level (NPS-Mo2C/C-0.5) exhibits excellent performance with an overpotential of 53 mV to achieve a current density of 20 mA cm−2, a Tafel slope of 72 mV dec−1 and good stability in acidic electrolytes. Based on the study of XPS, EPR and 31P MAS NMR, the excellent electrocatalytic performance could be attributed to the effective electronic configuration modulation of both Mo2C nanorods and the carbon matrix, derived from stronger synergistic N, P, S multi-doping coupling effects. This work provides a promising methodology for the design and fabrication of multi-doped transition metal based electrocatalysts via electronic structure engineering.

Highly efficient electrocatalytic hydrogen evolution promoted by O-Mo-C interfaces of ultrafine β-Mo2C nanostructures.

Optimizing interfacial contacts and thus electron transfer phenomena in heterogeneous electrocatalysts is an effective approach for enhancing electrocatalytic performance. Herein, we successfully synthesized ultrafine β-Mo2C nanoparticles confined within hollow capsules of nitrogen-doped porous carbon (β-Mo2C@NPCC) and found that the surface layer of molybdenum atoms was further oxidized to a single Mo–O surface layer, thus producing intimate O–Mo–C interfaces. An arsenal of complementary technologies, including XPS, atomic-resolution HAADF-STEM, and XAS analysis clearly reveals the existence of O–Mo–C interfaces for these surface-engineered ultrafine nanostructures. The β-Mo2C@NPCC electrocatalyst exhibited excellent electrocatalytic activity for the hydrogen evolution reaction (HER) in water. Theoretical studies indicate that the highly accessible ultrathin O–Mo–C interfaces serving as the active sites are crucial to the HER performance and underpinned the outstanding electrocatalytic performance of β-Mo2C@NPCC. This proof-of-concept study opens a new avenue for the fabrication of highly efficient catalysts for HER and other applications, whilst further demonstrating the importance of exposed interfaces and interfacial contacts in efficient electrocatalysis.

IrCo alloy nanoparticles supported on N-doped carbon for hydrogen evolution electrocatalysis in acidic and alkaline electrolytes.

Designing efficient and low-cost electrocatalysts for the hydrogen evolution reaction (HER) is of great importance to advance water splitting technology towards practical applications. Herein, we report the preparation of IrCo nanoparticles supported on nitrogen-doped carbon (IrCo/NC) as a HER electrocatalyst in acidic and alkaline electrolytes. The IrCo/NC composite is obtained by pyrolyzing an Ir-doped Co(OH)2 precursor on g-C3N4, and is endowed with N-doped carbon and uniform IrCo alloy nanoparticles via a crystal confinement resulting from the Ir-doping into the Co(OH)2 layer. Electrocatalytic analysis shows that the IrCo/NC electrode requires low overpotentials of 32 mV at 10 mA cm-2 in 0.5 M H2SO4 and 33 mV in 1 M KOH, which are superior to those of the Co/NC and IrCo alloys that are free of Ir-doping or N-doped carbon. The results provide a strategy for designing and preparing active noble-transition bimetallic alloy electrocatalysts as efficient HER catalysts.

Enhanced Reaction of Renewable Hydrogen Energy Production Using Platinum-based Nanoclusters

Objectives It would be essential for solving the global warming problem to use renewable energy as well as increase the efficiency of energy production. One of the renewable and efficient energy sources is hydrogen energy, and the electrochemical hydrogen evolution reaction (HER) is the most important reaction in the hydrogen energy production. For HER, inexpensive catalyst development is indispensible because the precious metal Pt is being used as the most efficient catalyst for HER. Methods Density functional theory (DFT) calculations were performed using the Vienna ab initio simulation package (VASP) to calculate atomic and electronic structures and total energies using the projector-augmented wave (PAW) method. Results and Discussion The HER efficiencies of Pt(111), Pt nanoclusters, and Pt-based core-shell nanoclusters were examined based on the hydrogen adsorption energies (Eads) by using the density functional theory (DFT) calculations. The DFT results demonstrate that Pt nanoclusters (0.5 ~ 2.1 nm in diameter) showed stronger hydrogen adsorption (Eads = -0.65 ~ -1.25 eV) than that of Pt(111) (Eads = -0.61 eV), implying a lower HER efficiency of Pt nanoclusters than Pt(111). On the other hand, a Rucore-Ptshell nanocluster (Eads = -0.48 eV) showed weaker hydrogen adsorption than Pt(111), indicating an increase in the HER efficiency. The weaker hydrogen adsorption on Rucore-Ptshell was attributed to the d;-band shift of Pt atoms further away from the Fermi level in negative direction due to the core Ru atoms. Conclusion By evaluating the HER efficiency using a descriptor of the hydrogen atom adsorption strength, a Ru-Pt core-shell (Rucore-Ptshell) nanocluster was expected to exhibit the highest HER efficiency among Pt(111), Pt55 nanocluster, and Mcore-Ptshell (M = Ni, Co, Mn, Cu, Ru, Ir and Au) nanoclusters. Key words: Hydrogen Evolution Reaction (HER), Platinum (Pt) Catalysts, Nanocluster, Core-shell, Density Functional Theory (DFT), d-Band Center Theory

A platinum nanowire electrocatalyst on single-walled carbon nanotubes to drive hydrogen evolution

Pertinent existing hydrogen technologies for energy storage require unsustainable amounts of scarce platinum group metals. Here, an electrocatalyst comprising high-aspect-ratio platinum nanowires (PtNWs) on single-walled carbon nanotubes (SWNTs) with ultralow Pt content (340 ngPt cm−2) is employed for hydrogen evolution reaction (HER). A comparable activity (10 mA cm−2 at −18 mV vs. RHE) to that of state-of-the-art Pt/C (38,000 ngPt cm−2) is reached in acidic aqueous electrolyte. This is attributed to favorable PtNW interaction with SWNTs and PtNW edge-sites which adsorb hydrogen optimally and aid at alleviating repulsive interactions. Moreover, the metallic nature of Pt, morphological effects and enhanced wetting contribute positively. The PtNW/SWNT relevance is emphasized at a proton-exchange-membrane electrolyzer generating stable voltage for more than 2000 h, successfully competing with the state-of-the-art reference but with one tenth of Pt mass loading. Overall, this work presents an unprecedently efficient HER catalyst and opens up avenues for PtNW/SWNT catalyzing other high-impact reactions.

Emergence of Si2BN Monolayer as Efficient HER Catalyst under Co-functionalization Influence

In the present work, we have envisaged the enhancement of hydrogen evolution reaction (HER) activity on stable Si2BN monolayer based on first-principles electronic structure calculations. Herein, w ...

Non-noble metal-nitride based electrocatalysts for high-performance alkaline seawater electrolysis

Seawater is one of the most abundant natural resources on our planet. Electrolysis of seawater is not only a promising approach to produce clean hydrogen energy, but also of great significance to seawater desalination. The implementation of seawater electrolysis requires robust and efficient electrocatalysts that can sustain seawater splitting without chloride corrosion, especially for the anode. Here we report a three-dimensional core-shell metal-nitride catalyst consisting of NiFeN nanoparticles uniformly decorated on NiMoN nanorods supported on Ni foam, which serves as an eminently active and durable oxygen evolution reaction catalyst for alkaline seawater electrolysis. Combined with an efficient hydrogen evolution reaction catalyst of NiMoN nanorods, we have achieved the industrially required current densities of 500 and 1000 mA cm−2 at record low voltages of 1.608 and 1.709 V, respectively, for overall alkaline seawater splitting at 60 °C. This discovery significantly advances the development of seawater electrolysis for large-scale hydrogen production.

Self-supported nickel nitride nanosheets as highly efficient electrocatalysts for hydrogen evolution

Ni3N has been demonstrated as an excellent hydrogen evolution reaction (HER) catalysts that contain active sites with hydrogen adsorption energy. However, the catalytic efficiency of Ni3N is hindered by its inferior electrical conductivity. Herein, we successfully present an effective strategy to boost the H adsorption capability and HER property of Ni3N supported by nickel foam is illustrated. Ni3N nanosheets/nickel foam (Ni3N NSs/NiF) achieve a super low overpotential of 34 mV at 10 mA cm−2 and a fairly small Tafel slope of 54 mV dec−1 in 1 M KOH aqueous solution. Focusing on a self-supported electrode structural design, Ni3N NSs/NiF composites catalysts possess following advantages: (1) abundant exposed edges deriving from thin Ni3N nanosheets; (2) high conductivity of the entire system generating from metallic metal nitrides integrated by metal substrate; (3) synergistic effect between Ni3N and nickel foam, and more effective facets to accelerated reaction kinetics. The developed compound is among the most active electrocatalysts based on non-precious catalysts, which expand and enrich the family of materials suitable as efficient HER catalysts.

Phosphorus-doped Co3Mo3C/Co/CNFs hybrid: A remarkable electrocatalyst for hydrogen evolution reaction

Exploring high-performance and low-cost electrocatalysts toward hydrogen evolution reaction aimed at generating hydrogen to alleviate the pressure of energy crisis is of extremely urgent. Herein, we report phosphorus-doped Co3Mo3C/Co/CNFs (termed P–Co3Mo3C/Co/CNFs) hybrid with unique three-dimensional network structure as efficient hydrogen evolution reaction catalyst. Note that the introduction of P can modulate electronic structure of Mo and Co centers to accelerate hydrogen evolution reaction kinetics. The P–Co3Mo3C/Co/CNFs exhibits low onset potential of −19 mV and Tafel slope of 64 mV dec−1 in 1 M KOH. It requires overpotential of only 81 mV to afford a current density of 10 mA cm−2 and presents long-time stability for more than 40 h at current density of ∼10 mA cm−2 and ∼50 mA cm−2. More excellently, this facilely prepared P–Co3Mo3C/Co/CNFs catalyst reveals promising application prospect in different kinds of water splitting devices. This work highlights an effective approach to perfect hydrogen evolution reaction catalytic performance via phosphorus-doped.

B-doping-induced amorphization of LDH for large-current-density hydrogen evolution reaction

Developing a platinum-free hydrogen evolution reaction (HER) electrocatalyst that can steadily drive a large current density is of great significance in a commercially electrochemical water splitting technology. Herein, we show that the B-doping-induced amorphization of crystalline layered double hydroxide (LDH) activates it as an extremely efficient HER catalyst. The amorphous B-incorporated nickel-cobalt LDH supported on the nickel foam (A-NiCo LDH/NF) can yield large current densities at small overpotentials (100 mA cm–2 at 151 mV, 500 mA cm–2 at 286 mV, and 1000 mA cm–2 at 381 mV) with high durability in alkaline medium even after 72 h, which is even better than commercial platinum. This work may provide a promising way for structure tuning of transition metal LDH to effectively boost HER efficiency towards practical water electrolysis.

Precious Metal Free Materials As Efficient Catalysts for Water Splitting

Precious Metal Free Materials as Efficient Catalysts for Water Splitting Pei Kang Shen*, Zhi Qun Tian Collaborative Innovation Center of Sustainable Energy Materials, Guangxi University100 Daxue Road, Nanning 530004, Guangxi, China*E-mail address: pkshen@gxu.edu.cn Water electrolysis is a promising approach for large-scale and sustainable hydrogen production. However, its kinetics is slow and requires precious metal catalysts to efficiently operate. Therefore, great efforts are being undertaken to design and prepare low-cost and highly efficient catalysts to boost the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Currently, we developed different noble metal free materials as efficient catalysts for HER, OER, and full water splitting. For HER, the catalysts with novel nanostructures were prepared, such as carbon-encapsulated WOx (WOx@C), N-doped porous MoN nanobelts, nitrogen and fluorine dual-doped porous graphene-nanosheets, K0.4TaO2.4F0.6 nanocubes, Ni3S2 nanowires, TiN nanowires, nanoflower-like MoO2, et al. For OER catalysts, the Mo- and Fe-modified Ni(OH)2/NiOOH nanosheets, nitrogen-decorated iron-nickel sulfide nanosheets, Mo-doped NiOOH nanosheets, tantalum dioxyfluoride, pristine carbon nanotubes, graphene supported MnO2 nanowires were studied. For full water splitting, the porous WO2 hexahedral networks, heteroatoms dual doped porous graphene nanosheets, three-dimensional porous MoNi4 networks, porous MoO2 nanosheets, dye functionalized carbon nanotubes were studied. The synthesized materials displayed excellent catalytic activity for hydrogen evolution, oxygen evolution, and full water splitting, and can be applied as low cost and highly active multifunctional catalysts with excellent ORR and OER performance. The improved activity and active origin of aforementioned catalysts are clarified through experimental analysis and DFT calculation. These studies pave the way for the design and development of cheaper, highly efficiently and more durable catalysts for wider applications.

Hierarchical NiMo alloy microtubes on nickel foam as an efficient electrocatalyst for hydrogen evolution reaction

Developing efficient, non-noble electrocatalysts for hydrogen evolution reaction (HER) is of high significance for future energy supplement, but challenging. NiMo alloy is a non-noble-metal-based efficient catalyst for HER due to its appropriate hydrogen binding energy and excellent alkali corrosion resistance. Herein, for the first time, we report the preparation of radially aligned NiMo alloy microtubes on Ni foam (NiMo MT/NF). The synthesized NiMo alloy catalyst was composed of the Ni10Mo phase; notably, this hierarchically structured material possessed abundant active sites and a high surface area, and exhibited efficient electronic transport properties. The NiMo MT/NF electrode exhibited a low overpotential of 119 mV at 10 mA/cm2 in a base solution, which was 50 mV less than that of NiMo alloy nanoparticles on NF (169 mV).