Efficient Catalyst For Hydrogen Production Research Articles

Iron doped nanocomposites based efficient catalyst for hydrogen production and reduction of organic pollutant

Iron doped nanocomposites based effective material were prepared for catalytic reduction of an organic pollutant and hydrogen production. Electrochemical production of hydrogen based on water splitting has been deliberated as an auspicious approach, however, the lethargic anodic oxygen evolution reaction (OER) restricts the effectiveness of water splitting. Also, active catalysts for catalytic reduction of organic pollutants are also highly required for the catalytic removal of organic pollutants. Therefore, in this manuscript, we report iron doped metal oxide nanocomposites (Fe2O3-ZnO and Fe-SnO2) as multifunctional catalysts for OER, hydrogen evolution reaction (HER) as well as catalytic reduction of organic pollutants. Therefore, efficient nano-catalyst based on iron oxide doped tin oxides and iron doped zinc oxide with long-term stability and efficient hydrogen generation and removal of organic pollutants has been developed. The catalytic efficiency of the developed materials was evaluated toward producing hydrogen and removing organic pollutants. In HER, it was found that Fe2O3-ZnO and Fe-SnO2 needs a low over potential to produce 10 mA cm−2 in 0.5 M KOH and 0.5 M H2SO4. Similarly, in OER, 600 mV is needed to drive the current density of 20 mA cm−2 in 1.0 M KOH using Fe2O3-ZnO. Fe2O3-ZnO illustrates lower Tafel slopes of 64.3 mV dec-1 and 96.0 mV dec-1 in HER using 0.5 M KOH and 0.5 M H2SO4, respectively, while in OER, the Tafel slope is 76.5 mV dec-1 using 1.0 M KOH. The catalytic efficiency of Fe2O3-ZnO and Fe-SnO2 was also evaluated for the removal of 4-nitrophenol and among them, Fe-SnO2 displayed good catalytic efficiency toward 4-nitrophenol reduction. 4-Nitrophenol was totally reduced in less than 5 min using Fe-SnO2 as a catalyst.

2H-MoS2 nanoflowers with exposed edges for hydrogen producing electrochemical cell

In this study, we report hexagonal MoS2 nanoflowers with well exposed edges as efficient catalyst for hydrogen production. The 2H-MoS2 nanoflowers based electrodes show a low overpotential of 0.193 V and a Tafel slope of 69 mV dec1 at a voltage sweep rate of 5 mV s−1 for hydrogen evolution reaction with excellent stability for more than 2500 cycle. We also demonstrate the production and collection of hydrogen using in-house developed electrochemical cell with 2H-MoS2 nanoflowers as cathode.

Iron doped Ni3S2 nanorods directly grown on FeNi3 foam as an efficient bifunctional catalyst for overall water splitting

The development of high-performance and inexpensive bifunctional electrocatalysts to replace precious metal catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) remains a thorny issue in the field of electrochemical water splitting. Here, a three-dimensional rods array catalysts of Ni3S2 doped with trace amount of Fe on foam FeNi3 (Fe-Ni3S2@FeNi3) are synthesized. It is found experimentally that Fe-Ni3S2@FeNi3 has excellent catalytic activity and corrosion resistance in both acidic, neutral and alkaline solutions. In 1.0 M KOH solution, only small overpotentials of 105 mV and 213 mV are required to achieve the current densities of 10 mA cm−2 for HER and OER respectively. In addition, Fe-Ni3S2@FeNi3-8 also exhibits excellent catalytic activity in 0.5 M H2SO4 solution (η10 = 48 mV) and 1.0 M PBS solution (η10 = 83 mV) for HER. In 1.0 M KOH and 0.33 M urea solution, Fe-Ni3S2@FeNi3-8 requires only 1.40 V to provide the current density of 10 mA cm−2 for urea oxidation reaction (UOR). As evidenced, doping Fe element into catalyst can significantly increase the catalytic activities for HER and OER. This work demonstrates a new and facile approach to prepare novel bimetallic transition metal catalysts as inexpensive alternatives to precious metal catalysts for efficient hydrogen production.

Mechanistic Analysis-Guided Pd-Based Catalysts for Efficient Hydrogen Production from Formic Acid Dehydrogenation

Heterogeneous catalysis of formic acid dehydrogenation at room temperature is a promising tactic for safely storing and producing H2 as an efficient energy carrier. Up to now, the catalysts for thi...

Ruthenium nanoparticles supported in the network of HES-p(AMPS) IPN hydrogel as efficient catalyst for hydrogen production from the hydrolysis of ethylenediamine bisborane

In this study, Ru(0) nanoparticles supported in 2-hydroxyethyl starch-p-(2-Acrylamido-2-methyl-1-propanesulfonic acid) interpenetrating polymeric network (HES-p(AMPS) IPN) were synthesized as hydrogel networks containing hydroxyethyl starch, which is a natural polymer with oxygen donor atoms. The structure and morphology of the prepared HES-p(AMPS) IPN hydrogel and Ru@HES-p(AMPS) IPN catalyst were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM). Ru@HES-p(AMPS) IPN was used as catalyst for hydrogen production from the hydrolysis of ethylenediamine bisborane (EDAB). The activation parameters for the hydrolysis reaction of EDAB catalyzed by Ru@HES-p(AMPS) IPN were calculated as Ea = 38.92 kJ mol−1, ΔH# = 36.28 kJ mol−1, and ΔS# = −111.85 J mol−1 K−1, respectively. The TOF for the Ru@HES-p(AMPS) IPN catalyst was 2.253 mol H2 (mol Ru(0) min)−1. It was determined that Ru@HES-p(AMPS) IPN, a reusable catalyst, still had 81.5% catalytic activity after the 5th use.

Methods for Electrocatalysis: Advanced Materials and Allied Applications

Two structurally analogous Anderson polyoxometalate (POM) supported copper complexes found to be an efficient catalyst for hydrogen production from neutral aqueous medium. These compounds, [Cr(OH)6Mo6O18{Cu(phen)(H2O)2}2][Cr(OH)6Mo6O18{Cu(phen)(H2O)Cl}2].5H2O (1) and [Al(OH)6Mo6O18{Cu(phen)(H2O)2}2][Al(OH)6Mo6O18{Cu(phen)(H2O)Cl}2].5H2O (2), catalyze electrochemical hydrogen evolution reaction (HER) from water (phosphate buffer, pH 7) with relatively low overpotentials of 300 mV and 644 mV at current density of 1 mA/cm2 respectively. Compounds 1 and 2 show remarkable Faradic efficiencies of 95.7% and 89.4% respectively. In terms of overpotential and Faradic efficiency, compound 1 turns out to be a better electrocatalyst for HER from water than compound 2. In this report, we have evidently proved that the active site of this electrochemical HER is the water coordinated Cu(II) center, supported onto POM cluster anion; the polyoxometalate, onto which these aqua-Cu(phen)-complexes are supported, plays an important role in making the overall system heterogeneous, for designing a better electrocatalyst for direct reduction of neutral water.

A novel synthesis of NiAl2O4 spinel from a Ni-Al mixed-metal alkoxide as a highly efficient catalyst for hydrogen production by glycerol steam reforming

A novel method was developed for the synthesis of a more easily reducible NiAl2O4 spinel, which was tested as catalyst for hydrogen production by glycerol steam reforming. A Ni-Al mixed-metal alkoxide was firstly prepared through solvothermal method and then calcined using a two-step calcination technique. XRD, N2 physisorption, H2-TPR, XPS, SEM, and TEM results show that this new catalyst is more readily reducible and possesses a more developed porous structure with higher surface area. It therefore exhibits high H2 yield (76.38 %) and glycerol conversion into gaseous products (95.42 %). To avoid or reduce coke formation, 10 wt.% CeO2 was incorporated into the catalyst structure. TGA, TEM, and Raman spectroscopy analyses reveal the suppression of coke by a large extent due to the formation of well-dispersed CeAlO3, which decreases significantly the filamentous carbon formation rate on nickel surface and promotes coke gasification by providing oxidative environment around nickel active sites.

Optimizing the preparation of Ni‐Ce‐Pr catalysts for efficient hydrogen production by n ‐dodecane steam reforming

Optimizing the preparation of Ni‐Ce‐Pr catalysts for efficient hydrogen production by <i>n</i> ‐dodecane steam reforming

Facile Fabrication of NiPt/CNTs as an Efficient Catalyst for Hydrogen Production from Hydrous Hydrazine

AbstractHydrogen generation through catalytically hydrous hydrazine has recently emerged as a promising strategy to meet the ever‐increasing demand for sustainable energy. However, it remains a challenging obstacle to design highly active catalysts as well as low‐cost. In this work, we designed a series of NiPt/CNTs catalysts, which were prepared via a facile wet chemical reduction method, employed it in the dehydrogenation of hydrous hydrazine. The crystalline structure, chemical states and morphology of the catalysts were also characterized in detail. Among these catalysts, Ni0.4Pt0.6/CNTs exhibits highest activity with a turnover frequency (TOF) of 1725.3 h−1 at 50 °C and a low Ea of 36.3 kJ/mol. Considering its cost‐effective and high performance, the Ni0.4Pt0.6/CNTs represent a promising catalyst to hydrolyze hydrous hydrazine for hydrogen generation.

Cathodic hydrogen recovery using Y zeolites loaded nickel(II) Oxide instead of Pt/C in microbial electrolysis cell

ABSTRACT A highly efficient electrode material is required to explore and apply to microbial electrolysis cell (MEC) with high hydrogen evolution reaction (HER) efficiency. Pt/C was one of the most efficient catalysts for hydrogen production in current lab research, but it was expensive and some chemicals in wastewater were prone to Pt poisoning, which was a great limitation in application. Thus, a cheap and effective nickel(II) Oxide/Y (NiO/Y) material was prepared by using Y zeolites as carrier loaded with NiO in this study, which was used in MEC to evaluate the hydrogen evolution performance in comparison with Pt/C. The results indicated that NiO/Y composites showed a competitive HER performance to Pt/C. The linear sweep voltammetry (LSV) tests and Tafel plots showed that the NiO/Y composites exhibited the best catalytic activity for HER. In the MEC tests, the NiO/Y composites cathode was comparable with the Pt/C cathode in terms of current densities and energy efficiency. The coulombic efficiency, cathodic energy efficiency rate and hydrogen production rate obtained with NiO/Y cathode MEC was 85.88 ± 6.5%, 228.39 ± 3.2% and 0.83 ± 0.05 m3/m3d under, respectively, which were slightly higher than those obtained with the Pt/C cathode MEC. It was concluded that even with the cheap Y zeolites as the supports, the NiO/Y materials showed the superior performance, which was attributed to a good dispersing of the active component of NiO on the large specific surface area of Y zeolites and the fast escape of hydrogen bubbles from microporous and mesoporous structure of Y zeolites.

Monophosphine‐substituted diiron azadithiolate complexes: New syntheses, characterization and electrochemical properties

Investigating the synthesis and properties of diiron azadithiolate complexes is one of the key topics for mimicking the active site of [FeFe]‐hydrogenases, which might be very useful for the design of new efficient catalysts for hydrogen production and the development of a future hydrogen economy. A series of new phosphine‐substituted diiron azadithiolate complexes as models for the active site of [FeFe]‐hydrogenases are described. A novel and efficient way was firstly established for the preparation of phosphine‐substituted diiron azadithiolate complexes. The reaction of Fe2(μ‐SH)2(CO)6 and phosphine ligands L affords the intermediate Fe2(μ‐SH)2(CO)5L (A). The intermediate reacts in situ with a premixed solution of paraformaldehyde and ammonium carbonate to produce the target phosphine‐substituted diiron azadithiolate complexes Fe2[(μ‐SCH2)2NH](CO)5L (1a–1f) (L = P(C6H4–4‐CH3)3, P(C6H4–3‐CH3)3, P(C6H4–4‐F)3, P(C6H4–3‐F)3, P(2‐C4H3O)3, PPh2(OCH2CH3)). Furthermore, reactions of the intermediate A with I‐4‐C6H4N(CH2Cl)2 in the presence of Et3N give the phosphine‐substituted diiron azadithiolate complexes Fe2[(μ‐SCH2)2NC6H4–4‐I](CO)5L (2a–2e) (L = P(C6H4–4‐CH3)3, P(C6H4–3‐CH3)3, P(C6H4–4‐F)3, P(C6H4–3‐F)3, P(2‐C4H3O)3). All the complexes were fully characterized using elemental analysis, IR and NMR spectroscopies and, particularly for 1a, 1c–1e, 2a and 2c, single‐crystal X‐ray diffraction analysis. In addition, complexes 1a–1f and 2a–2e were found to be catalysts for H2 production under electrochemical conditions. Density functional theory calculations were performed for the reactions of Fe2(μ‐SH)2(CO)6 + P(C6H4–4‐CH3)3.

Pitaya pulp structural cobalt–carbon composite for efficient hydrogen generation from borohydride hydrolysis

The design and synthesis of high efficiency catalysts for hydrogen generation and storage are the key factors for large-scale hydrogen use. Herein, a Pitaya pulp structural cobalt-based carbon nanocatalyst is synthesized. The 5–10 nm Co/CoOx particles are uniformly distributed in the 500-nm spherical carbon matrix and enable efficient catalytic performance during hydrogen generation from the alkaline NaBH4 and NH3BH3 solutions at 3998 mL min−1·gCo−1 for NaBH4 and 4677 mL min−1·gCo−1 for NH3BH3. The catalyst nanoparticles were prepared by a facile one-pot solution reaction, pyrolysis at high temperature, and oxidation in air. The coexistence of various valence states of Co in the composite material is observed by utilizing various characterization methods. Co nanoparticles fixed in the carbon matrix effectively prevent particles from aggregation and loss. This unique structure's similarity with Pitaya pulp, its synergistic effects, and its self-stirring mode enable its effective catalytic performance and good stability. The results provide a reference direction for the design and synthesis of unique structure catalysts for efficient hydrogen production.

Electrospun carbon nanofiber-encapsulated NiS nanoparticles as an efficient catalyst for hydrogen production from hydrolysis of sodium borohydride

Carbon nanofibers (CNFs) incorporating NiS nanoparticles (NPs), namely NiS@CNFs were prepared by one-step electrospinning and successfully employed as a catalyst for hydrogen production from hydrolytic dehydrogenation of sodium borohydride (SBH). As-prepared NiS@CNFs, composed of polyacrylonitrile (PAN), nickel acetate, and ammonium sulfide, was calcined at 900 °C in argon atmosphere, and characterized using standard surface science techniques. The combined results revealed the growth of NiS NPs inside the CNFs, hence confirmed the presence of elemental Ni, S, and C. The as-prepared NiS@CNFs catalyst has a significantly higher surface area (650.92 m2/g) than the reported value of 376 m2/g. Importantly, this catalyst exhibited a much higher catalytic performance, for H2 production from SBH, than that of Ni@CNFs, as evidenced by its low activation energy (∼25.11576 kJ/mol) and their Rmax values of 2962 vs. 1770 mL/g·min. Recyclability tests on using NiS@CNFs catalyst showed quantitatively production (∼100% conversion) of H2 from SBH and retained up to 70% of its initial catalytic activity after five successive cycles. The low cost and high catalytic performance of the designed NiS@CNFs catalyst enable facile H2 production from readily available hydrogen storage materials.

Anderson polyoxometalate supported Cu(H2O)(phen) complex as an electrocatalyst for hydrogen evolution reaction in neutral medium

Two structurally analogous Anderson polyoxometalate (POM) supported copper complexes found to be an efficient catalyst for hydrogen production from neutral aqueous medium. These compounds, [Cr(OH)6Mo6O18{Cu(phen)(H2O)2}2][Cr(OH)6Mo6O18{Cu(phen)(H2O)Cl}2].5H2O (1) and [Al(OH)6Mo6O18{Cu(phen)(H2O)2}2][Al(OH)6Mo6O18{Cu(phen)(H2O)Cl}2].5H2O (2), catalyze electrochemical hydrogen evolution reaction (HER) from water (phosphate buffer, pH 7) with relatively low overpotentials of 300 mV and 644 mV at current density of 1 mA/cm2 respectively. Compounds 1 and 2 show remarkable Faradic efficiencies of 95.7% and 89.4% respectively. In terms of overpotential and Faradic efficiency, compound 1 turns out to be a better electrocatalyst for HER from water than compound 2. In this report, we have evidently proved that the active site of this electrochemical HER is the water coordinated Cu(II) center, supported onto POM cluster anion; the polyoxometalate, onto which these aqua-Cu(phen)-complexes are supported, plays an important role in making the overall system heterogeneous, for designing a better electrocatalyst for direct reduction of neutral water.

A PdAg-CeO2nanocomposite anchored on mesoporous carbon: a highly efficient catalyst for hydrogen production from formic acid at room temperature

Herein, CeO2-modified PdAg alloy nanocomposites were anchored on mesoporous carbon, showing exceedingly high catalytic activity for HCOOH dehydrogenation at room temperature.

Ni anchored C2N monolayers as low-cost and efficient catalysts for hydrogen production from formic acid

Noble-metal-free catalysts are highly desirable for hydrogen generation from formic acid dehydrogenation. Herein, using first-principles density functional theory calculations, we design a series of nickel-anchored nitrogenated holey two-dimensional carbon structures (Nix@C2N, x = 1–3) as formic acid dehydrogenation catalysts. For all Nix@C2N surfaces, the formic acid dehydrogenation preferably proceeds via the formate pathway. The effective barrier continuously decreases for formic acid dehydrogenation while increases for hydrogen formation from Ni1@C2N to Ni3@C2N. The side reaction producing carbon monoxide and water via the carboxyl or formyl pathway cannot occur on Ni1@C2N or Ni2@C2N and is not preferred on Ni3@C2N, and thus, the Nix@C2N catalysts possess excellent selectivity of hydrogen. Notably, the unsaturated nitrogen atom of substrate also participates in the reaction and exhibits synergetic effect with the nickel component in Ni1@C2N and Ni2@C2N. The Gibbs free energetic span analysis predicts that the order of reactivity is Ni2@C2N (0.79 eV) > Ni1@C2N (0.87 eV) > Ni3@C2N (1.23 eV), and the turnover frequency of Nix@C2N is evaluated. The results are compared with the experimental and theoretical reports of some palladium-based catalysts. The present work suggests that the Nix@C2N may be promising noble-metal-free catalysts for formic acid dehydrogenation with high performance and low cost.

Core–Shell Engineering of Pd–Ag Bimetallic Catalysts for Efficient Hydrogen Production from Formic Acid Decomposition

To develop high-performance bimetallic catalysts, fine control over both the ligand and strain effects of secondary elements on the catalytic function of primary elements is crucial. Here we introduce an approach to produce Pd–Ag bimetallic core–shell nanocatalysts with synergistic regulation of the ligand and strain effects of Ag. Through precise core–shell engineering, (PdAg alloy core)@(ultrathin Pd shell) nanocrystals with controlled core compositions and shell thicknesses in addition to a well-defined octahedral morphology could be realized. The prepared octahedral PdAg@Pd core–shell nanocrystals exhibited pronounced catalytic performance toward hydrogen production from formic acid decomposition. The maximum catalytic activity was achieved with PdAg@Pd nanocrystals consisting of PdAg alloy cores with an average Pd/Ag atomic ratio of 3.5:1 and 1.1 atomic layer of Pd shells, which showed a record high turnover frequency of 21 500 h–1 at 50 °C. This catalytic function could be attributed to the optimize...

Carbon Nanotubes Supported Nickel as the Highly Efficient Catalyst for Hydrogen Production through Glycerol Steam Reforming

Different amounts of nickel were loaded on carbon nanotubes (CNTs) by an impregnation method and characterized by N2 adsorption/desorption isotherms, X-ray diffraction, X-ray photoelectron spectros...

Morphological Engineering of Winged Au@MoS2 Heterostructures for Electrocatalytic Hydrogen Evolution.

Molybdenum disulfide (MoS2) has been recognized as a promising cost-effective catalyst for water-splitting hydrogen production. However, the desired performance of MoS2 is often limited by insufficient edge-terminated active sites, poor electrical conductivity, and inefficient contact to the supporting substrate. To address these limitations, we developed a unique nanoarchitecture (namely, winged Au@MoS2 heterostructures enabled by our discovery of the "seeding effect" of Au nanoparticles for the chemical vapor deposition synthesis of vertically aligned few-layer MoS2 wings). The winged Au@MoS2 heterostructures provide an abundance of edge-terminated active sites and are found to exhibit dramatically improved electrocatalytic activity for the hydrogen evolution reaction. Theoretical simulations conducted for this unique heterostructure reveal that the hydrogen evolution is dominated by the proton adsorption step, which can be significantly promoted by introducing sufficient edge active sites. Our study introduces a new morphological engineering strategy to make the pristine MoS2 layered structures highly competitive earth-abundant catalysts for efficient hydrogen production.

Salicylaldimine-Ni complex supported on Al2O3: Highly efficient catalyst for hydrogen production from hydrolysis of sodium borohydride

In this study, the Ni-based complex catalyst containing nickel of 1% supported on Al2O3 is used as for the hydrogen production from NaBH4 hydrolysis. The maximum hydrogen production rate from hydrolysis of NaBH4 with Ni-based complex catalyst supported on Al2O3 containing nickel of 1% is 62535 ml min−1 g−1 (complex catalyst containing 1 wt% Ni). The resulting complex catalyst is characterised by XRD, XPS, SEM, FT-IR, UV, and BET surface area analyses. The Arrhenius activation energy is found to be 27.29 kJ mol−1 for the nickel-based complex catalyst supported on Al2O3. The reusability of the catalyst used in this study has also been investigated. The Ni-based complex catalyst supported on Al2O3 containing nickel of 1% is maintained the activity of 100% after the fifth use, compared to the first catalytic use. The n value for the reaction rate order of NaBH4 is found to be about 0.33.