Synergistic Effect Of Nickel Research Articles

Synergistic effect of nickel and graphite powders on the thermoelectric properties of ultra-high-performance concrete containing steel fibers and MWCNTs

The study investigates the influence of multi-walled carbon nanotubes (MWCNTs) and conductive powders, namely nickel powder (NP) and graphite powder (GP), on the mechanical and thermoelectric properties of ultra-high-performance concrete (UHPC). Flowability tests indicate that the addition of MWCNTs and conductive powders affects the flow diameter, with higher concentrations resulting in decreased flowability. Thermalgravimetric analysis and Fourier transform infrared spectroscopy reveal that the enhancement of the hydration reaction by 0.1 % MWCNTs in UHPC reaches saturation at this concentration. Pore structure analysis demonstrates a reduction in porosity and a denser structure upon the addition of 0.1 % MWCNTs. Mechanical tests indicate that the incorporation of 0.1 % MWCNTs enhances compressive and tensile strengths, whereas the introduction of 0.3 % MWCNTs diminishes the mechanical performance. Moreover, the electrical conductivity and thermoelectric effect are enhanced with the addition of MWCNTs and conductive powders. However, a decline in thermoelectric effect is observed when 0.3 % MWCNTs are added, although the conductivity remained high. The optimal thermoelectric performance is achieved with the combination of 0.3 % MWCNTs and 5 % NP, yielding a maximum power factor (PF) of 2148.2 μW/m·K2 and a figure of merit (ZT) of 4.9 × 10⁻7.

Synergistic effect of nickel and temperature on gene expression, multiple stress markers, and depuration: an acute toxicity in fish.

Aquatic animals are prone to extinction due to metal pollution and global climate change. Even though the fish and their products are also unsafe for human consumption, their exports have been rejected due to inorganic and organic contaminants. Nickel (Ni) is a metal that induces toxicity and accumulates in the aquatic ecosystem, posing health threats to humans, animals, and fish. In light of the above, our present investigation aimed to determine the median lethal concentration (96h-LC50) of nickel alone and concurrent with high temperature (34°C) (Ni + T) using static non-renewable bioassay toxicity test in Pangasianodon hypophthalmus. The groups treated under exposure to Ni reared under control condition (25-28.9°C) and Ni + T exposure group reread under 34°C. In this study, chose the definitive dose of Ni and Ni + T as 17, 18, 19, and 20mg L-1 after the range finding test. The median lethal concentration of Ni and Ni + T was determined as 19.38 and 18.75mg L-1, respectively at 96h. Oxidative stress viz. catalase (CAT), superoxide dismutase (SOD), glutathione-s-transferase (GST), and glutathione peroxidase (GPx) in the liver, gill, and kidney were noticeably elevated with Ni and Ni + T during 96h. Whereas, the CAT, GPx, and SOD gene expressions were significantly upregulated with Ni and Ni + T. Trilox equivalent anti-oxidant capacity (TEAC), cupric reducing anti-oxidant capacity (CUPRIC), ferric reducing ability of plasma (FRAP), ethoxy resorufin-O-deethylase (EROD), and acetylcholine esterase (AChE) were reduced due to exposure to Ni and Ni + T. Cellular metabolic stress and lipid peroxidation were highly affected due to Ni and Ni + T exposure. The immunological status, as indicated by total protein, albumin, globulin, A:G ratio, and nitro blue tetrazolium chloride (NBT), was severely affected by the toxicity of Ni and Ni + T. Moreover, the gene expression of interleukin (IL), tumor necrosis factor (TNFα), toll-like receptor (TLR), and total immunoglobulin (Ig) was remarkably downregulated following exposure to Ni and Ni + T. HSP 70, iNOS expression, ATPase, Na + /K + -ATPase, cortisol, and blood glucose was significantly elevated with Ni and Ni + T in P. hypophthalmus. The bioaccumulation of Ni in fish tissues and experimental water was determined. The kidney and liver tissues were highly accumulated with Ni, whereas DNA damage was reported in gill tissue. Interestingly, depuration study revealed that at the 28th day, the Ni bioaccumulation was below the maximum residue limit (MRL) level. Therefore, the present study revealed that Ni and Ni + T led to dysfunctional gene and metabolic regulation affecting physiology and genotoxicity. The bioaccumulation and depuration results also indicate higher residual occurrence of Ni in water and aquatic organisms for longer periods.

Synergistic effect of nickel and calcium dual-atomic sites to facilitate electrochemical CO2 reduction to methanol: Combining high activity and selectivity

Atomically dispersed transition metal sites embedded into nitrogen-doped graphene provide promising potential for the electrochemical CO2 reduction to CO, but the catalytic efficiency for further hydrogenation to methanol is seriously restricted. Herein, combining the advantage of single transition metal, alkaline-earth metal, and multiple active sites, we designed nickel and calcium dual-atomic site catalysts (Ni-Ca DACs) supported on N-doped graphene to enable CO2 hydrogenation. First-principles calculations reveal that the electron-rich Ni atom serves as the carbon adsorption site, and the adjacent Ca atom with electron-deficient properties acts as the oxygen adsorption site, which largely stabilizes many CHxOy species through the O-Ca bond, especially the *OCHO, thus facilitating CO2 reduction. More importantly, a synergistic adsorption process on Ni-Ca sites promote the formation of *CHO species that is considered as the key intermediate for generation of multi-electron products. Different from the single Ni or Ca catalysts that produce mainly CO or HCOOH, the Ni-Ca DACs can selectively catalyze CO2 reduction to CH3OH, with a low limiting potential of −0.52 V, while suppressing the hydrogen evolution reaction. The outstanding catalytic activity originates from the tuned polarized charge and d-band center of active sites by synergistic interaction of adjacent Ni and Ca atoms.

Synergistic Effect of Nickel and Cobalt in Nanowire Array for High Energy Storage with Rapid Charge Transfer in Asymmetric Supercapacitor

AbstractWe introduce a unique asymmetric supercapacitor design that combines a vertically aligned Ni−Co alloy‐type nanowire (NiCoNW) array electrode with a graphene flakes (GFs) electrode. The sandwiching of these two electrodes enables the device to operate at a high working potential window of 2.0 V. The improved response of the device is attributed to the asymmetric design and a high charge transfer in the NiCoNWs compared with pure metals. The optimized presence of Co in the alloy increases the rate of hydroxide formation in an alkaline solution during the gas evolution reaction. The use of GFs to modify the graphite electrode (GFs@Graphite) provided a more stable response at high current densities. We obtain extremely stable cyclic voltammetry (CV) plots even at very high scan rates (500 V/s) and galvanostatic charge–discharge curves with longer charge–discharge times. The highest capacitance achieved for the assembled device (Asy‐NiCoNWs/GFs@Graphite) is 339 F/cm3 (volumetric) at a current density of 5.0 A/cm3. In addition, a remarkable cycling retention of ∼100 % is observed after 10000 continuous potential cycles.

Upcycling waste polycarbonate plastics into jet fuels over NiCo/C by catalytic tandem hydropyrolysis/hydrodeoxygenation

Chemical upcycling of waste polycarbonate (PC) into jet fuels through catalytic tandem hydropyrolysis/hydrodeoxygenation (THH) is a practical strategy to generate value from polymer wastes. A process which combining hydropyrolysis with vapor phase hydrodeoxygenation (HDO) was proposed in a two-stage pressurized fixed-bed reactor. A cobalt-based Metal-Organic Framework (MOF) derived material supported with nickel was designed for the vapor-phase HDO of phenolic compounds derived from PC hydropyrolysis. The product distribution could be regulated by optimizing reaction pressure in the reactor and catalyst to PC mass ratio. Experimental results showed that the products are all phenolic compounds in the absence of catalysts, while a high yield of jet-fuel range cycloalkanes (100%) was obtained under optimized conditions (7 bar H2 pressure and 5:1 catalyst to PC mass ratio) over NiCo/C. The high HDO activity of NiCo/C depends on the synergistic effect of nickel and cobalt atoms, which facilitates the elimination of phenolic hydroxyl group and hydrogenation of benzene ring. This work puts forward an efficient approach for upcycling PC waste into jet fuels with MOF-derived NiCo/C as a catalyst.

Hydrochloric acid etching induced flower-like NiFe-layered double hydroxide as efficient electrocatalyst for oxygen evolution reaction

To meet the increasing demand for clean energy storage in modern society, the development of efficient and low-cost electrocatalysts that can overcome and accelerate the sluggish kinetics of electrochemical reactions is required. NiFe-Layered Double Hydroxide (NiFe-LDH) is regarded as an effective oxygen evolution reaction (OER) electrocatalyst, but most of the current synthesis methods, such as electrochemical deposition and calcination, are complex and difficult to operate on a large scale. Herein, we report the preparation of NiFe-LDH directly on a NiFe foam substrate using a simple two-step method in which the surface oxide layer is first removed from NiFe foam using a room-temperature hydrochloric acid bath for 10 min, followed by soaking in hydrochloric acid solution at 80 °C for 20 h. The prepared NiFe foam etched by hydrochloric acid for 20 h (NiFe-20-H) exhibited a unique hydrangea flower-like structure with a large surface area and abundant active sites, which is favorable for OER. Combining the structural advantages of large number of exposed active sites, synergistic effects of nickel and iron, and the convenient charge transfer path provided by the NiFe foam, the resulting NiFe-20-H sample achieved a current density of 10 mA cm−2 at an extremely low overpotential (241 mV) and a small Tafel slope of 44.2 mV dec−1, providing excellent long-term stability in alkaline electrolyte, surpassing pristine NiFe foam reported in our work, as well as many state-of-the-art electrocatalysts and IrO2. This efficient synthesis of NiFe-LDH provides a new approach for the development of non-noble OER electrocatalysts and has wide application prospects in the field of electrocatalysts.

Anchored lithium-rich manganese nanoparticles boosting Nd-BiVO4 photoanode for efficient solar-driven water splitting

The recombination rate of electron-hole pairs is much faster than the process of hole capture-electron transfer, which is an important reason for limiting the large-scale application of BiVO4 photoanode. Here, we have prepared a new LMNCO-Nd-BiVO4 photoanode using the rare earth element neodymium (Nd) as a dopant and loaded with the lithium-rich manganese material Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO) as a co-catalyst. The new photoanode exhibited excellent photoelectrochemical (PEC) water oxidation performance and high stability. The photocurrent density reached 2.7 mA cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE), which is 2.8 times than bare BiVO4. A series of characterizations demonstrated that Nd doping increases carrier concentration, reduces impedance. The nickel of LMNCO co-catalyst played the role of hole extraction, while cobalt played the active site. With the synergistic effect of nickel and cobalt, the photogenerated holes can be smoothly transferred to the semiconductor/electrolyte interface and quickly participated in the water oxidation reaction, which significantly improved the photoelectrochemical water oxidation performance and stability of BiVO4 photoanode. This work is the first time to apply lithium materials to the field of PEC water oxidation, which provides a new idea for the design of BiVO4 photoanode in the future.

3D HCN nanotexture with synergistic effect of nickel and hole scavengers for enhancing photocatalytic H2 production: Role of morphology and influential parameters

• 3D porous graphic carbon nitride was fabricated using facile hydrothermal approach. • Higher porous structure with faster charge carrier separation was observed in 3D structure. • Using 3D Ni/HCN, significantly higher H 2 was obtained compared to bulk g-C 3 N 4 . • Using methanol, much higher H 2 yield was obtained than ethanol, glycerol and TEOA. • Catalyst loading, feed concentration and sacrificial reagents greatly affect activity and stability. Well-designed three-dimensional (3D) nanotextures of graphitic carbon nitride (g-C 3 N 4 ), synthesized using template free single step method and mediated with nickel as a noble free metal, for solar hydrogen production, has been investigated. The photoactivity was investigated in a slurry type continuous flow photoreactor system by using different influential parameters such as hole scavengers, diffusion effects, time, and mass transfer. Compared to bulk g-C 3 N 4 , H 2 yield was increased with 3D hierarchical carbon nitride (HCN) nanotexture. The H 2 evolution rate was reached to 1310 µmol g −1 h −1 with optimized 2 % Ni loading to 3D HCN. This H 2 evolution rate was 19.8 and 24.9 times higher than it was generated using 3D HCN and g-C 3 N 4 , respectively. The special interlayer opening, more light penetration and suppressed charge carrier recombination were the main contributors for this photoactivity enhancement. Among the different influential parameters, lower viscosity, higher number of protons and less diffusion effects were promising to give significantly higher H 2 production. The stability of nanotextures was entirely dependent on the attached reactants over the nickel reactive sites, which was more promising for Triethanolamine (TEOA) than using methanol. This newly developed low-cost 3D HCN can be promising in solar energy conversion and other energy applications.

Synergistic Effect of Nickel on Tungsten Oxide Hydrate (WO3·H2O) As a Photoanode for Dye-Sensitized Solar Cells

Synergistic Effect of Nickel on Tungsten Oxide Hydrate (WO3·H2O) As a Photoanode for Dye-Sensitized Solar Cells

Design and Synthesis of Heterometallic Ni–Co Organic Frameworks as Anode Materials for High-Performance Lithium Storage

Reasonable design of high-rate, long-life anode materials is the key to manufacturing advanced lithium-ion batteries. Herein, we synthesized the heterometallic (Ni, Co) 4,4′-biphenyldicarboxylic metal organic framework (NiCo-MOF-1) and heterometallic (Ni, Co) 2,2′-bipyridine-5,5′-dicarboxylic metal organic framework (NiCo-MOF-2) by solvothermal method, and explored the applications as anode materials for lithium-ion batteries in depth. It was demonstrated that the initial discharge/charge specific capacities of NiCo-MOF-1 and NiCo-MOF-2 reached 2.04/1.12 and 1.99/1.11 mAh cm−2 at a current density of 0.1 mA cm−2 and the voltage window of 0.01 ∼ 3.0 V, respectively. Similarly, NiCo-MOF-2 could maintain a specific discharge/charge capacity of 0.65/0.64 mAh cm−2 after 150 cycles, which was higher than that of NiCo-MOF-1 (0.45/0.43 mAh cm−2). In addition, NiCo-MOF-2 delivers outstanding rate performance (0.29/0.29 mAh cm−2 at 1.0 mA cm−2), which came down to the strong conjugated carboxylate π–π interaction and the synergistic effect of nickel and cobalt bimetals. Through the kinetic analysis, the pseudocapacitance contribution was as high as 61.7% at 0.5 mV s−1. Ex-situ XPS verified the coordination mechanism of Li+ and COO− rings with benzene ring in NiCo-MOF-2 thus achieving high lithium storage capacity.

Three-phase composites of NiFe2O4/Ni@C nanoparticles derived from metal-organic frameworks as electrocatalysts for the oxygen evolution reaction

Composite electrocatalysts of carbon and metals or metal compounds with homogeneous active sites can be obtained through the carbonization of metal organic framework (MOF) materials under inert atmosphere. In this work, a three-phase composite electrocatalysts NiFe2O4/Ni@C were prepared via pyrolysis from self-assembled MOF nanosheets aggregates. The excellent electrocatalytic activity of the obtained electrocatalysts with various Ni:Fe ratios is demonstrated. Especially, the NiFe2O4/Ni@C sample with the mole ratio of Ni:Fe = 1:1 can use the overpotential (η) of 330 and 423 mV to drive 10 and 50 mA cm−2 respectively. After 80 000 s/22 h, the current density could retained 90% of the initial current density. The excellent activity and stability of the electrocatalysts are attributed to nickel and iron ions with uniform dispersion at atomic level in the NiFe2O4 phase and the synergistic effect of nickel and NiFe2O4 nanoparticles with amorphous carbon atoms or nanoparticles around.

Merger of C-F and C-N Bond Cleavage in Cross-Electrophile Coupling for the Synthesis of gem-Difluoroalkenes.

Herein we successfully applied Katritzky salts as the alkyl electrophile in the reductive allylic defluorinative cross-coupling reaction with α-trifluoromethyl alkenes. The merger of C-F and C-N bond cleavage via the synergistic effect of nickel and zinc allows the efficient synthesis of diverse gem-difluoroalkenes with a good tolerance for various functional groups.

Ni1‐xCoxOy, Ni1‐xCoxSy and Ni1‐xCoxPy Catalysts Prepared from Ni1‐xCox‐ZIF‐67 for Hydrogen Production by Electrolysis in Alkaline Media

AbstractThe uniform homeotypic bimetallic Ni1‐xCoxOy, Ni1‐xCoxSy and Ni1‐xCoxPy catalysts were synthesized from Ni1‐xCox‐ZIF‐67 crystals (120‐135 nm) reacting with oxygen, sublimed sulfur and sodium hypophosphite, respectively under control conditions. The catalysts were deposited on glassy carbon electrode (GCE), and their electro‐catalytic activity for hydrogen production in alkaline media by electrolysis was investigated. The electrocatalytic activity of the catalysts towards hydrogen evolution reaction (HER) decreased in the following order Ni0.1Co0.9Py>Ni0.2Co0.8Oy>Ni0.5Co0.5Sy>Ni0.1Co0.9‐ZIF‐67. The Ni0.1Co0.9Py exhibited the highest electrocatalytic activity towards HER due to the high crystallinity, high specific surface area and the synergistic effect of nickel and cobalt that accelerate the electron transfer process.

Ultrathin NiFeZn-MOF nanosheets containing few metal oxide nanoparticles grown on nickel foam for efficient oxygen evolution reaction of electrocatalytic water splitting

Usually, metallic organic frameworks (MOFs) based electrocatalysts are prepared by pyrolysis of MOFs. And it is improved that the research on direct use of MOFs as electrocatalysts through the development of two-dimensional (2D) shaped MOFs direction is feasible. In this paper, a kind of ultrathin NiFeZn-MOF nanosheets containing few metal oxide nanoparticles grown on nickel foam (NiFeZn-MNS/NF) are successfully synthesized, and they are used as catalyst for the oxygen evolution reaction (OER) and overall water splitting. The NiFeZn-MNS/NF catalyst behaves the most excellent electrocatalytic performance with the best overpotential of 350 mV at 50 mA cm−2 and has the best current density stability with the 5% drop of the initial polarization current density at the end of 120 h. The voltage of NiFeZn-MNS/NF as a bifunctional overall water-splitting catalyst is 1.52 V at the current density of 10 mA cm−2, which is superior to commercial noble metal electrocatalytic combination of RuO2/NF(+)//Pt-C/NF(−)(1.63 V). The structure and morphology of the nanosheets and the synergistic effect of nickel, iron and zinc ions enhance the catalytic activity. While the addition of zinc ion promotes the rapid growth of nanosheets on nickel foams, which further improves the stability of nanosheets.

Prussian blue analogues-derived bimetallic phosphide hollow nanocubes grown on Ni foam as water splitting electrocatalyst

The development of highly active and stable electrocatalysts for the water splitting using the earth-abundant transition metal as precursor is important for the renewable energy application. Prussian blue analogues (PBAs) are regarded as an ideal precursor for the preparation of electrocatalysts because of its abundant metal elements and various derived porous nanostructures. In this work, the (NiCo)2P hollow nanocubes, which are firmly grown on Ni foam, are prepared by PBAs and used as an water splitting electrocatalyst with high activity and stability in 1 M KOH solution. Benefiting from the synergistic effect of nickel and cobalt, hollow structure and high double-layer capacitance, the as-synthesized (NiCo)2P/NF catalyst shows an excellent electrocatalytic performance for the water splitting. To achieve current density of 10 mA cm−2, for HER and OER, this material requires overpotentials of 162 mV and 220 mV, respectively. As an integrated electrocatalyst for water splitting, the (NiCo)2P/NF needs a cell voltage of 1.62 V to achieve current density of 10 mA cm−2. Furthermore, this material has long-term electrocatalytic stability (over 30 h). The high catalytic activity of this material is attributed to the synergistic effect of component and the hollow structure of catalyst. This facile and novel method of preparing bimetallic phosphide electrocatalysts with hollow structure provides a broadened space for the design and synthesis of non-noble metal catalysts in the future.

Nickel-Catalyzed Heteroarenes Cross Coupling via Tandem C–H/C–O Activation

Inert aryl methyl ethers as coupling components via C–O activation have been established with a Ni catalyst for C–H activation of heteroarene. The key to simultaneous C–H/C–O bond activation is the use of sterically demanding o-tolylMgBr. The protocol is effective for a wide scope of substrates including naphthyl methyl ethers, anisoles, and a variety of other heteroarene derivatives. Detailed mechanistic studies indicated that the C–O cleavage is assisted via synergistic effect of nickel and Grignard reagent in this C–H/C–O reaction, which is supported by DFT calculation. At this stage, single-electron transfer can be ruled out as a main operative process for this tandem strategy.

NiGa modified carbon-felt cathode for hydrogen production

In this study, known electrocatalytic active metal nickel and low amount of gallium were electrodeposited on carbon felt electrode for hydrogen evolution reaction in alkali medium. Morphological and structural analyses of prepared electrodes were determined by scanning electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic activity of obtained electrodes for hydrogen evolution reaction was determined with cathodic polarization curves, electrochemical impedance spectroscopy, discharge potential measurements, hydrogen volume measurements at constant potential and durability tests. It was found that the electrodeposition of low amount of gallium over the nickel coated carbon felt electrode increases the hydrogen evolution reaction activity and decreases the overpotential for hydrogen region. The electrocatalytic activity of nickel and gallium deposited on carbon felt electrode was explained with active sites of surface and synergistic effect of nickel and gallium created by high surface area of carbon felt.

Nickel‐Nanoparticles on Doped Graphene: A Highly Active Electrocatalyst for Alcohol and Carbohydrate Electrooxidation for Energy Production

AbstractNickel nanoparticles supported on nitrogen doped graphene (Ni−NGr) as highly efficient electrocatalyst were synthesized via controlled thermal annealing using a mixture of graphene oxide, nickel nitrate and uric acid. The synthesized Ni−NGr catalyst presented excellent electrocatalytic performance for ethanol, glucose and glycerol oxidation, stemming from the synergistic effects of nickel and N‐graphene. The electrocatalytic activity was enhanced by the high surface area and nitrogen‐based active sites of pyridinic and graphitic N in doped graphene. These N‐moieties enhanced the accessibility of active sites while preventing agglomeration of nickel nanoparticles on the doped graphene surface. The hybrid electrocatalyst performances were significantly improved and are suited for electrooxidation application in fuel cells.

Carbon nanotubes-modified graphitic carbon nitride photocatalysts with synergistic effect of nickel(II) sulfide and molybdenum(II) disulfide co-catalysts for more efficient H2 evolution

This work reports effective photocatalysts which are composed of carbon nitride (CN), carbon nanotubes (CNTs), MoS2 and NiS, for hydrogen evolution aiming at energy crises and environmental pollutions. The morphologies and optical properties of the photocatalysts were carefully characterized and their photocatalytic performance towards water reduction was studied afterwards. MoS2 and NiS exhibit a significant synergistic effect working as co-catalysts. Compared to MoS2/CN nanohybrid, carbon nanotubes and NiS improved the absorption of visible light and the separation of charge carriers effectively. NiS-MoS2/CNTs/CN catalyst exhibits high performance for H2 evolution and the optimized rate is 309.9 μmol·h−1·g−1 with no noble metals under visible light irradiation. The study demonstrates a non-noble metal photocatalyst system for effective generation of hydrogen with low cost.

Improved Dehydrogenation Properties of LiBH4 Using Catalytic Nickel- and Cobalt-based Mesoporous Oxide Nanorods.

Lithium borohydride (LiBH4 ) with a theoretical hydrogen storage capacity of 18.5 wt % has attracted intense interest as a high-density hydrogen storage material. However, high dehydrogenation temperatures and limited kinetics restrict its practical applications. In this study, mesoporous nickel- and cobalt-based oxide nanorods (NiCo2 O4 , Co3 O4 and NiO) were synthesized in a controlled manner by using a hydrothermal method and then mixed with LiBH4 by ball milling. It is found that the dehydrogenation properties of LiBH4 are remarkably enhanced by doping the as-synthesized metal oxide nanorods. When the mass ratio of LiBH4 and oxides is 1:1, the NiCo2 O4 nanorods display the best catalytic performance owing to the mesoporous rod-like structure and synergistic effect of nickel and cobalt active species. The initial hydrogen desorption temperature of the LiBH4 -NiCo2 O4 composite decreases to 80 °C, which is 220 °C lower than that of pure LiBH4 , and 16.1 wt % H2 is released at 500 °C for the LiBH4 -NiCo2 O4 composite. Meanwhile, the composite also exhibits superior dehydrogenation kinetics, which liberates 5.7 wt % H2 within 60 s and a total of 12 wt % H2 after 5 h at 400 °C. In comparison, pure LiBH4 releases only 5.3 wt % H2 under the same conditions.