Hydrogen Production Applications Research Articles

Efficient flower-like ZnSe/Cu0.08Zn0.92S photocatalyst for hydrogen production application

Efficient flower-like ZnSe/Cu0.08Zn0.92S photocatalyst for hydrogen production application

Advancements in hydrogen energy research with the assistance of computational chemistry

Hydrogen and electricity are the leading energy sources for most applications in the near future. With the rapid development of computers and computational chemistry methods, the research in hydrogen production, infrastructure materials, storage, and utilization more than ever benefits from close interactions with computational chemistry. The present review aims at presenting the modern state of hydrogen energy chemical research in all processes of hydrogen economy. Directions of further research efforts are given in the context of chemometrics and computational chemistry advancements. Problems of computational chemistry that hinder rapid progress are given and their possible solutions are outlined. It is expected that new artificial neural network (ANN) algorithms will play a decisive role in the creation of dependable computational chemistry methods and their application for hydrogen infrastructure, production, storage, and consumption.

Doped nanomaterials: Application in hydrogen production via photocatalytic water splitting

A green and sustainable energy resource is needed to meet global energy demand and minimize environmental pollution. Hydrogen (H2) is a clean and renewable energy that can be generated via photocatalytic splitting of water. Recent studies on the application of doped photocatalysts in water splitting are numerous. Here, metal and non-metal ion doped photocatalysts with their H2 production capacity has been reviewed. Firstly, the influence of metal/non-metal dopants on the properties of host semiconductors were deduced. Then, metal (alkaline earth, transition and inner-transition metal ions) and non-metal ions doped photocatalysts with their water splitting capacity were discussed. Different metal compounds and carbon nitride materials were used as host photocatalysts. The experimental conditions which influence the efficiency of the doped photocatalysts in H2 generation were highlighted. Strategies such as multi-ionic doping process, composite construction and defect creation for the enhancement of activity of doped photocatalysts in water splitting were also summarized. At last, the challenges, future directions and conclusions derived from this literature review were outlined.

Biochars from Olive Stones as Carbonaceous Support in Pt/TiO2-Carbon Photocatalysts and Application in Hydrogen Production from Aqueous Glycerol Photoreforming.

Several biochars were synthesized from olive stones and used as supports for TiO2, as an active semiconductor, and Pt as a co-catalyst (Pt/TiO2-PyCF and Pt/TiO2-AC). A third carbon-supported photocatalyst was prepared from commercial mesoporous carbon (Pt/TiO2-MCF). Moreover, a Pt/TiO2 solid based on Evonik P25 was used as a reference. The biochars used as supports transferred, to a large extent, their physical and chemical properties to the final photocatalysts. The synthesized catalysts were tested for hydrogen production from aqueous glycerol photoreforming. The results indicated that a mesoporous nature and small particle size of the photocatalyst lead to better H2 production. The analysis of the operational reaction conditions revealed that the H2 evolution rate was not proportional to the mass of the photocatalyst used, since, at high photocatalyst loading, the hydrogen production decreased because of the light scattering and reflection phenomena that caused a reduction in the light penetration depth. When expressed per gram of TiO2, the activity of Pt/TiO2-PyCF is almost 4-times higher than that of Pt/TiO2 (1079 and 273 mmol H2/gTiO2, respectively), which points to the positive effect of an adequate dispersion of a TiO2 phase on a carbonaceous support, forming a highly dispersed and homogeneously distributed titanium dioxide phase. Throughout a 12 h reaction period, the H2 production rate progressively decreases, while the CO2 production rate increases continuously. This behavior is compatible with an initial period when glycerol dehydrogenation to glyceraldehyde and/or dihydroxyacetone and hydrogen predominates, followed by a period in which comparatively slower C-C cleavage reactions begin to occur, thus generating both H2 and CO2.

CdS/TiO2 nano hybrid heterostructured materials for superior hydrogen production and gas sensor applications

In efforts to minimize environmental pollution and carbon-based gas emissions, photocatalytic hydrogen production and sensing applications at ambient temperature are important. This research reports on the development of new 0D/1D materials based on TiO2 nanoparticles grown onto CdS hetersturctured nanorods via two-stage facile synthesis. The titanate nanoparticles when loaded onto CdS surfaces at an optimized concentration (20 mM), exhibited superior photocatalytic hydrogen production (21.4 mmol/h/gcat). The optimized nanohybrid was recycled for 6 cycles up to 4 h, indicating its excellent stabity for a prolonged period. Also, the photoelectrochemical water oxidation in alkaline medium was investigated to offer the optimized CRT-2 composite with 1.91 mA/cm2@0.8 V vs. RHE (0 V vs. Ag/AgCl) that was used for effective room-temperature NO2 gas detection exhibiting a higher response (69.16%) to NO2 (100 ppm) at room temperature at the lowest detection limit of ∼118 ppb than the pristine counterparts. Further, NO2 gas sensing performance of CRT-2 sensor was increased using UV light (365 nm) activation energy. Under the UV light, the sensor exhibited a remarkable gas sensing response quick response/recovery times (68/74), excellent long-term cycling stability, and significant selectivity to NO2 gas. Due to high porosity and surface area values of CdS (5.3), TiO2 (35.5), and CRT-2 (71.5 m2/g), excellent photocatalytic H2 production and gas sensing of CRT-2 is ascribed to morphology, synergistic effect, improved charge generation, and separation. Overall, 1D/0D CdS@TiO2 is proved to be an efficient material for hydrogen production and gas detection.

Dispersing small Ru nanoparticles into boron nitride remodified by reduced graphene oxide for high-efficient electrocatalytic hydrogen evolution reaction

Ruthenium (Ru) electrocatalysts suffer from excessive aggregation during the hydrogen evolution reaction (HER), which hinders their practical application for hydrogen production. Hexagonal boron nitride (h-BN) is a potential carrier that could solve the above problem, but its wide band gap and low conductivity become obstacles. Herein, we provide a new, facile, low-cost, and effective strategy (killing two birds with one stone) to overcome the above issues. After modifying h-BN with reduced graphene oxide (rGO), a small amount of Ru nanoparticles (NPs) (2.2 %) are dispersed into BN with approximately uniform distribution and size control of Ru nanoparticles (∼3.85 nm). The strong synergy between Ru NPs and BN@C in the optimal Ru/BN@C (Ru wt.% = 2.22 %) electrocatalyst endows it an outstanding HER activity, with small HER overpotentials (η10 = 32 mV, 35 mV) and low Tafel slopes (33.89 mV dec−1, 37.66 mV dec−1) in both 1 M KOH and 0.5 M H2SO4 media, respectively, along with good long-term stability for 50 h. Based on density functional theory (DFT) calculations, the addition of Ru to BN has been successful in creating fresh active sites for H*, with good possible adsorption/desorption ability (ΔGH* = −0.24 eV) while preserving low water dissociation (ΔGb = 0.46 eV) in an alkaline environment. As a result, the Ru/BN composite exhibits outstanding HER activity in both acidic and alkaline conditions. Furthermore, this study provides, for the first time, a template-free strategy to develop a good and low-cost supporter (BN) for dispersing other noble metals and the formation of highly efficient HER/OER electrocatalysts.

Bifunctional hierarchical NiCoP@FeNi LDH nanosheet array electrocatalyst for industrial-scale high-current-density water splitting

Aiming to design and prepare non-noble metal electrocatalysts for hydrogen production at high current density (HCD), NiCoP@FeNi LDH hierarchical nanosheets were deposited on nickel foam progressively using a hydrothermal-phosphorization-electrodeposition process. For hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), NiCoP@FeNi LDH/NF requires only 195 and 230 mV overpotentials to reach 1000 mA cm−2, respectively. For overall water splitting, only 1.70 V is required at 1000 mA cm−2. This is the largest value for non-noble metal-based electrocatalysts reported so far at HCD. The hierarchical structure exhibits good electron transport capability and the porous-macroporous structure enhances the gas release rate, resulting in enhanced hydrogen production at HCD. Especially, the synergistic effect of NiCoP and FeNi LDH contributes to the adsorption-desorption equilibrium of intermediate radicals during the reaction process and ultimately enhances the catalytic activity. This work provides useful direction for industrial-scale hydrogen production applications at HCD.

One-pot fabrication CoS2 modified MoS2-g-C3N4 ternary heterostructure composites with enhanced photocatalytic hydrogen production from water

In this work, we prepared several CoS2-MoS2-g-C3N4 ternary heterojunction photocatalysts in-situ synthesized at one-pot high temperature processing. The spectroscopic and optoelectronic properties of the samples were analyzed by fluorescence and electrochemical methods, while the photocatalytic hydrogen production activity and stability of the different samples were investigated under visible light conditions (λ ≥ 420 nm). The results showed that the 0.02-CoS2-MoS2-g-C3N4 sample exhibited excellent photocatalytic production performance. It's because of the improved separation and transport capacity of photogenerated electrons and holes, which based on the effect of heterojunction between MoS2 and g-C3N4. The introduction of CoS2 could be further enhance the photocatalytic hydrogen production performance due to the increased active center and reducing the reaction energy barrier. This study can provide a new insight in the practical applications for photocatalytic hydrogen production.

Modulating the electronic structure of CoS2 by Sn doping boosting urea oxidation for efficient alkaline hydrogen production

Urea electrocatalytic oxidation afforded by renewable energies is highly promising to replace the sluggish oxygen evolution reaction in water splitting for hydrogen production while realizing the treatment of urea-rich waste water. Therefore, the development of efficient and cost-effective catalysts for water splitting assisted by urea is highly desirable. Herein, Sn-doped CoS2 electrocatalysts were reported with the engineered electronic structure and the formation of Co-Sn dual active sites for urea oxidation reaction (UOR) and hydrogen evolution reaction (HER), respectively. Consequently, the number of active sites and the intrinsic activity were enhanced simultaneously and the resultant electrodes exhibited outstanding electrocatalytic activity with a very low potential of 1.301 V at 10 mA·cm−2 for UOR and an overpotential of 132 mV at 10 mA·cm−2 for HER. Therefore, a two-electrode device was assembled by employing Sn(2)-CoS2/CC and Sn(5)-CoS2/CC and the constructed cell required only 1.45 V to approach a current density of 10 mA·cm−2 along with good durability for at least 95 h assisted by urea. More importantly, the assembled electrolyzer can be powered by commercial dry battery to generate numerous gas bubbles on the surface of the electrodes, demonstrating the high potential of the as-fabricated electrodes for applications in hydrogen production and pollutant treatment at a low-voltage electrical energy input.

Comparative analysis of associated cost of nuclear hydrogen production using IAEA hydrogen cost estimation program

The interest in non-electric applications of nuclear energy is rising ranging from hydrogen production, district heating, seawater desalination, and various industrial applications to provide long-term answers for a variety of energy issues that both present and future generations will confront. Hydrogen is a dynamic fuel that can be used across all industrial sectors to lower carbon intensity. This study, therefore, aims at estimating the cost of nuclear hydrogen production from some light water reactors using International Atomic Energy Agency (IAEA) Hydrogen Calculator (HydCalc) program and comparing the result with similar existing studies conducted by other scholars using the Hydrogen Economic Evaluation Program (HEEP) program. The study employs six existing Light Water Reactors (LWRs) comprised of Korea Advanced Power Reactor 1400 MW electricity (APR1400), Russian VVER-1200, Davis-Besse Nuclear Power Plant in Ohio, Prairie Island NPP in Minnesota, Nine Mile Point NPP in New York, and Arizona Public Service's Palo Verde NPP to evaluate the Levelized cost of nuclear hydrogen production. Estimation of hydrogen demand was performed without carbon dioxide (CO2) tax since nuclear power has zero CO2 emission. The Levelized costs obtained using IAEA HydCalc and HEEP Programme were compared as follows; APR1400 cost are 2.6$/kg and 3.18$/kg, VVER1200 cost are 3.8$/kg and 3.44$/kg; Exelon cost are 1.7$/kg and 4.85$/kg; Davis Besse cost are 3.9$/kg and 3.09$/kg; Parlo Verde cost are 3.5$/kg and 4.77$/kg; Xcel Energy cost are 3.63$/kg and 0.69$/kg. The cost of hydrogen production using HEEP for Xcel Energy's Prairie Island NPP is 0.69 $/kg. This is because the reactor utilizes High Temperature Steam Electrolysis, method of hydrogen production, while the other methods employs Low Temperature Electrolysis. The results shows that the final price of the hydrogen for each reactor technology depends not only on the production method but also on the cost of the nuclear power plant and the production rate of the hydrogen plant.

One-step growth of Ni3Fe-Fe3C heterostructures well encapsulated in NCNTs as superior self-supported bifunctional electrocatalysts for overall water splitting

Ni3Fe-Fe3C heterostructures well encapsulated in N-doped carbon nanotubes (Ni3Fe-Fe3C@NCNTs) were fabricated by a facile one-step pyrolysis-growth approach. Thanks to the merits of abundant active sites, multiple heterogeneous interfaces, large electrochemical active surface area, robust structure, self-supporting configuration and remarkable synergistic effect, Ni3Fe-Fe3C@NCNTs exhibits excellent bifunctional catalytic activity and stability toward both HER and OER in alkaline media. Moreover, the Ni3Fe-Fe3C@NCNTs||Ni3Fe-Fe3C@NCNTs electrolyzer requires an ultralow voltage of 1.80 V for overall water splitting to reach a current density of 300 mA cm−2, and it keeps stable over 300 h for continuous hydrogen generation with 100% Faradaic efficiency, surpassing Pt/C||RuO2 electrolytic cell and showing great promise for industrial application in green hydrogen production.

Electronic modulation with Pt-incorporated NiFe layered double hydroxide for ultrastable overall water splitting at 1000 mA cm−2

Achieving large current density is crucial to the practical application of large-scale hydrogen production by water splitting, but it is hindered by sluggish and unstable catalysts. Herein, a Pt-induced NiFe layered double hydroxide (Pt-NiFe LDH) nanosheet is synthesized for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). It affords 10 mA cm–2 at overpotentials of only 198 mV and 36 mV for OER and HER, respectively. Impressively, an alkali-electrolyzer (Pt-NiFe LDH || Pt-NiFe LDH) exhibits a stable cell voltage of 1.887 V to deliver a current density of 1000 mA cm–2 over 3000 h. The introduction of Pt modulates the electronic structure on the surface of NiFe LDH by charging redistribution at the interface and decreasing the Gibbs free energy change (ΔG) for the potential determining step (from *O to *OOH) during OER. This work provides a facile strategy for developing catalysts for large current density water splitting.

Disordered and ultrafine PtNiMo alloy for superior electrocatalytic hydrogen evolution in alkaline

Developing efficient and stable Pt-based alloy catalysts toward hydrogen evolution reaction (HER) is great of importance for the industrial and sustainable applications of hydrogen production. Herein, we fabricate the defective and ultrafine PtNiMo catalyst with modified electronic structure and alloy structure through the introduction of saturated potassium chloride solution. In alkaline conditions, the PtNiMo alloy catalyst exhibits the ultralow overpotentials of 39 and 319 mV at the current density of 10 and 300 mA cm−2, respectively, accompanied with small Tafel slope of 31 mV dec−1 and high mass activities of 6.1 A gPt−1 at the overpotential of 75 mV. Moreover, the PtNiMo alloy catalyst shows superior electrocatalytic durability, together with negligible decay over 5000 cyclic voltammetry cycles for HER operations. The work offers an efficient route to achieve highly efficient electrocatalysts with defective structure for energy storage and conversion devices.

Mechanochemical Synthesis of Lead-Free Perovskite-Like MA3 Bi2 I9 for Photo-Catalytic Hydrogen Production.

In this study, a highly air stable and eco-friendly methyl ammonium bismuth iodide (MA3 Bi2 I9 ) perovskite-like material has been prepared. After physiochemical characterizations, the synthesized MA3 Bi2 I9 was utilized as photo-catalyst towards hydrogen production. It is important to design and synthesize lead (Pb)-free perovskite-like material (MA3 Bi2 I9 ) for photo-catalytic hydrogen-production applications. The synthesized MA3 Bi2 I9 exhibits excellent photo-catalytic hydrogen generation with a production rate of 11.43 μmolg-1 h-1 . In the presence of a platinum co-catalyst, the hydrogen production rate further increases to 172.44 μmolg-1 h-1 . The MA3 Bi2 I9 photo-catalyst also demonstrates excellent cyclic stability.

NiMo-MOF-Derived Carbon-Armored Ni4Mo Alloy of an Interwoven Nanosheet Structure as an Outstanding pH-Universal Catalyst for Hydrogen Evolution Reaction at High Current Densities

Development of highly efficient and stable non-precious metal-based pH-universal catalysts for hydrogen evolution reaction (HER) at high current densities remains challenging for water electrolysis-based green hydrogen production. Herein, a simple solvothermal process was developed to synthesize a NiMo metal-organic framework (MOF), from which a carbon-armored Ni4Mo alloy of an interwoven nanosheet structure was derived with a two-stage thermal treatment, to serve as a high-performance pH-universal HER catalyst. It requires low overpotentials of 22, 48, and 98 mV to achieve a current density of -10 mA cm-2 and 192, 267, and 360 mV to deliver an ultrahigh current density of -500 mA cm-2 in alkaline, acidic, and neutral media, respectively, and exhibits remarkable operational stability at an ultrahigh initial current density of -500 mA cm-2 for over 50 h, making it promising for applications in large-scale green hydrogen production. The success can be attributed to the unique catalyst design of a carbon-armored, composition-optimized NiMo alloy of an advantageous nanostructure of interwoven nanosheets for enhanced utilization of active sites and mass transfer of electrolytes and gaseous products, made possible with a MOF-derivation fabrication approach.

Defect-Rich PdIr Bimetallene Nanoribbons with Interatomic Charge Localization for Isopropanol-Assisted Seawater Splitting.

Metallene with outstanding physicochemical properties is an efficient two-dimensional electrocatalysts for sustainable hydrogen (H2 ) production applications. However, the controllable fabrication of extended atomically thin metallene nanoribbons remains a formidable challenge. Herein, this work proposes a controllable preparation strategy for atomically thin defect-rich PdIr bimetallene nanoribbons (PdIr BNRs) with a thickness of only 1.5nm for the efficient and stable isopropanol-assisted seawater electrolytic H2 production. When using PdIr BNRs as catalyst to build an isopropanol-assisted seawater electrolysis system, a voltage of only 0.38V is required at @10mA cm-2 to achieve energy-saving H2 production, while producing high value-added acetone at the anode. The aberration-corrected high-resolution transmission electron microscopy (HRTEM) clearly reveals that the PdIr BNRs possess abundant structural defects, which can additionally serve as highly catalytically active sites. Density functional theory (DFT) calculations combined with X-ray absorption spectroscopy studies reveal that the introduction of Ir atoms can induce the formation of a localized charge region and shift the d-band center of Pd down, thereby reducing the adsorption energy on the catalyst in favor of the rapid desorption of H2 . This work opens the way for the controllable design and construction of defect-rich atomically thin metallene nanoribbons for efficient electrocatalytic applications.

Charge Separation Enhancement Enables Record Photocurrent Density in Cu2ZnSn(S,Se)4 Photocathodes for Efficient Solar Hydrogen Production

AbstractCu2ZnSn(S,Se)4 (CZTSSe) is a promising light absorbing semiconductor for solar energy conversion in photovoltaic cells and photo‐electrochemical (PEC) water‐splitting devices, owing to its earth‐abundant constituents, adjustable band‐gap, and superior absorption coefficient. However, the severe charge carrier recombination and the sluggish charge separation efficiency are the main issues obstructing the enhancement of device performance. In this work, a planar‐type Mo/CZTSSe/CdS/TiO2/Pt photocathode is fabricated. High‐quality CZTSSe film with compact and uniform crystal grains can be obtained via a two‐step process involving solution processed spin coating and thermally processed selenization. When an appropriate film thickness is used, both bulk defects and surface/interface defects are passivated, significantly suppressing the defects‐assisted recombination. Moreover, the benign energy band alignment of CZTSSe/CdS heterojunction is favorable to enhance photo‐generated charge separation and transfer efficiency. A remarkable photocurrent density of 40.40 mA cm−2 (at 0 VRHE) can be achieved, approaching to its theoretical value of 42.85 mA cm−2, and representing the highest value reported to date for kesterites‐based photocathodes. A champion CZTSSe photocathode with half‐cell solar‐to‐hydrogen conversion efficiency of 6.47% suggests a bright future for efficient solar hydrogen production applications.

Interface Engineering of MOF-Derived NiMoO4@NiFeP Core-Shell Nanorods for Energy-Saving Hydrogen Evolution via Urea Electrolysis.

The development of multifunctional and durable electrocatalysts for hydrogen energy production via an energy-saving avenue is urgently desired. Urea electrolysis by substituting the oxygen evolution reaction (OER) with a more oxidizable urea oxidation reaction (UOR) has been widely used to realize energy-saving hydrogen production. Herein, metal-organic framework (MOF)-derived interface-engineered NiMoO4@NiFeP core-shell nanorods as electrocatalysts are constructed. Due to the integration of the advantages of the interface synergistic effect between the NiMoO4 core and NiFeP shell, the as-fabricated NiMoO4@NiFeP electrocatalyst demonstrates remarkable electrocatalytic performance toward the hydrogen evolution reaction (HER), OER, and UOR. In the urea electrolysis system, an ultralow cell voltage of 1.30 V is needed to drive the current density of 10 mA cm-2, which is 140 mV lower than that of the conventional overall water splitting system. The cost-efficient and high-performance NiMoO4@NiFeP electrocatalyst paves the way to explore practical applications of energy-saving hydrogen production.

Mesoporous core/shell MnFe2O4 nanocomposite derived from facile sonoelectrochemical process: An eco-friendly method for rapid synthesis and versatile industrial applications

Background: Replacing the current usage of toxic, hazardous, irreversible materials in existing industrial production for various applications into eco-friendly material with easy availability and finding an economic synthesis method with structure tunable properties to produce effective magnetic nanocomposite are still need to be developed for advanced chemical technology. Methods: Mesoporous core/shell MnFe2O4 nanocomposite have been synthesized in this report at 15 min using a facile, eco-friendly sonoelectrochemical process. Significant findings: The presence of manganese over magnetite (Fe3O4) was confirmed through FTIR, XRD, elemental mapping and EDS studies. The size and shape of the nanocomposite were analyzed from FESEM and HRTEM analyses. It was revealed that the synthesized nanocomposites are spherical in shape and have an average diameter of 65±10 nm with 10±2 nm shell thickness. Encapsulating manganese over core Fe3O4 nanoparticles had improved the thermal stability up to 7% than the mere Fe3O4 which was confirmed by thermogravimetry analysis. The BET analysis had revealed that the sonoelectrochemically synthesized nanocomposites are having higher surface area of 385.7 m2 g-1 and possess a mesoporous nature with a mean pore diameter of 1.90 nm. Based on these superior properties, the core/shell MnFe2O4 nanocomposite could be utilized as a promising material towards various industrial applications such as heavy metal removal, hydrogen production, hyperthermia, Li-ion battery, drug delivery, catalysis, and sensor applications.

Catalyst-Support Interactions Promoted Acidic Electrochemical Oxygen Evolution Catalysis: A Mini Review.

In the context of the growing human demand for green secondary energy sources, proton-exchange membrane water electrolysis (PEMWE) is necessary to meet the high-efficiency production of high-purity hydrogen required for proton-exchange membrane fuel cells (PEMFCs). The development of stable, efficient, and low-cost oxygen evolution reaction (OER) catalysts is key to promoting the large-scale application of hydrogen production by PEMWE. At present, precious metals remain irreplaceable in acidic OER catalysis, and loading the support body with precious metal components is undoubtedly an effective strategy to reduce costs. In this review, we will discuss the unique role of common catalyst-support interactions such as Metal-Support Interactions (MSIs), Strong Metal-Support Interactions (SMSIs), Strong Oxide-Support Interactions (SOSIs), and Electron-Metal-Support Interactions (EMSIs) in modulating catalyst structure and performance, thereby promoting the development of high-performance, high-stability, low-cost noble metal-based acidic OER catalysts.