Hydrogen Production Research Articles

Enhanced Electrocatalytic Urea Synthesis over Iron-Doped InOOH Nanosheets under Ambient Conditions.

Ambient urea synthesis via C-N coupling from CO2 and nitrate reduction offers an attractive alternative to the Bosch-Meiser route, but it is hindered by the lack of efficient catalysts. Herein, we report that Fe-doped InOOH nanosheets effectively catalyze the coreduction of CO2 and nitrate, giving a high Faradaic Efficiency of 26.9%, a yield rate of 980.6 μg h-1 mgcat.-1, and a good durability. Theoretical calculations further elucidate that iron dopants can tailor the reactivity of the In site, facilitating the hydrogenation of the key *CO2NH2 intermediate and suppressing the hydrogen production with a higher energy barrier.

Joint Electrons and Photons Transfer from Dual‐Functional WO3:Yb,Er to Zn0.5Cd0.5S for Efficient H2 Evolution

AbstractUtilization of the near‐infrared (NIR) light in the solar spectrum is critical for efficiency improvement of photocatalytic H2 evolution. However, common semiconductors have low response to the NIR light and narrow bandgap semiconductors have inappropriate redox potentials. Here, the study presents a new dual‐functional up‐conversion strategy in one sensitizer for promoting photocatalytic hydrogen production reactions by converting NIR light to visible light and high‐energy electrons simultaneously, via photon‐photon conversion and photo‐electronic process, respectively. Using WO3:Yb,Er as the sensitizer and Zn0.5Cd0.5S as the hydrogen evolution reaction catalyst, a photocatalytic hydrogen release rate of 24.3 mmol g−1 h−1 under simulated solar‐light has been achieved without using any co‐catalyst. After loading Ni2P as a co‐catalyst, the photocatalytic hydrogen production performance can be further improved to 41.3 mmol g−1 h−1 at 10 °C and 93.3 mmol g−1 h−1 under non‐temperature‐controlled conditions, exceeding most photocatalysts. This work offers a new strategy to improve the NIR light utilization of the solar‐light for promoting photocatalytic hydrogen generation through synergistic photo‐optical, photo‐electronic, and photo‐thermal effects.

Efficient and Ultrastable Seawater Electrolysis at Industrial Current Density with Strong Metal-Support Interaction and Dual Cl--Repelling Layers.

Direct seawater electrolysis is emerging as a promising renewable energy technology for large-scale hydrogen generation. The development of Os-Ni4Mo/MoO2 micropillar arrays with strong metal-support interaction (MSI) as a bifunctional electrocatalyst for seawater electrolysis is reported. The micropillar structure enhances electron and mass transfer, extending catalytic reaction steps and improving seawater electrolysis efficiency. Theoretical and experimental studies demonstrate that the strong MSI between Os and Ni4Mo/MoO2 optimizes the surface electronic structure of the catalyst, reducing the reaction barrier and thereby improving catalytic activity. Importantly, for the first time, a dual Cl- repelling layer is constructed by electrostatic force to safeguard active sites against Cl- attack during seawater oxidation. This includes a strong Os─Cl adsorption and an in situ-formed MoO4 2- layer. As a result, the Os-Ni4Mo/MoO2 catalyst exhibits an ultralow overpotential of 113 and 336mV to reach 500mA cm-2 for HER and OER in natural seawater from the South China Sea (without purification, with 1m KOH added). Notably, it demonstrates superior stability, degrading only 0.37 µV h-1 after 2500 h of seawater oxidation, significantly surpassing the technical target of 1.0 µV h-1 set by the United States Department of Energy.

Nickel Hydroxysulfide Electrocatalyst Promotes Urea Oxidation for Energy‐Saving Hydrogen Production

AbstractThe occurrence of oxygen evolution reaction (OER) almost consumes most of the electric energy of hydrogen production by electrocatalytic water splitting. The energy required in the process of electrochemical hydrogen production can be reduced by choosing urea oxidation reaction (UOR) instead of OER. In this work, nickel hydroxysulfide is synthesized on nickel foam (NiSOH/NF) and its electrocatalytic performance was tested in UOR. Experimental results show that the vulcanization catalyst requires a low potential of 1.38 V (vs RHE) to achieve a current density of 100 mA cm−2 in an electrolyte containing 0.5 M urea, which is 270 mV lower than the conventional OER process. This innovative approach has yielded a substantial reduction in the cell voltage necessary for overall water splitting under two electrode system, thereby enhancing its efficiency and feasibility.

Long-Term Selective Photoelectrochemical Glycerol Oxidation via Oxygen Vacancy Modulated Tungsten Oxide with Self-Healing.

The photoelectrochemical selective oxidation of biowaste glycerol into the high value-added material, along with hydrogen production, holds significant promise for advancing renewable and sustainable energy technologies. Here, the surface oxygen state of tungsten oxide is modified to selectively oxidize glycerol into glyceraldehyde, a high-value-added material, and the selectivity is maintained over a prolonged period using the photo-stimulated self-recovery capability. The surface-coordinated photoelectrode exhibits high charge transfer efficiency to glycerol and favorable glycerol adsorption capacity, enabling the selective conversion of glycerol. At 1.2 VRHE in a 2m glycerol electrolyte adjusted to pH 2, the tungsten oxide photoelectrode achieves a photocurrent density of 2.58mA cm-2 and a production rate of 378.8mmol m-2h-1 with selectivity of 86.1%. The high selectivity is preserved for 18 h by utilizing the self-healing capability of tungsten oxide to restore initial states modified by photoelectrochemical oxidation. This work sheds light on the design of highly efficient metal oxide photoelectrodes for selective biomass oxidation over extended periods.

Early-stage Testing of Thermal Power Dispatch Simulator for Subjective Mental Workload and Evolution Time

The excess thermal energy produced by nuclear power plants (NPPs) during low electricity demands can be utilized in industrial processes, such as hydrogen production, through a thermal power dispatch (TPD) system. Initial testing of the first iteration of a single-train TPD design with a manual control mode at the Idaho National Lab (INL) revealed a high operator workload and degraded control capability. The current study evaluated the impact of an enhanced dual-train TPD design on operators’ subjective mental workload and evolution task-time while completing two operating scenarios in manual and automatic control modes. The results showed no statistically significant difference between participants’ mental workload using both control modes. Evolution time in automatic control mode took a shorter time than in manual control, with participants completing all evolutions in less than the 10-min set as the design specification limit. The shorter evolution time is discussed within the context of plant safety and operational efficiency.

Photocatalytic hydrogen production and sulfamerazine degradation via a novel dual S-scheme photocatalyst: Nanocomposite synthesis, characterization and mechanism insights

Creating highly effective photocatalysts is crucial for harnessing solar energy to degrade pollutants and produce hydrogen (H₂). In this study, we successfully synthesized a novel dual S-scheme iron oxide (Fe₂O₃)/bismuth oxide (Bi₂O₃)/titanium dioxide (TiO₂) ternary photocatalyst using a straightforward method. This photocatalyst was employed for efficient photocatalytic water splitting and the degradation of the antibiotic sulfamerazine (SMZ) under visible light. Various characterization and photoelectrochemical techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Brunauer–Emmett–Teller surface area analysis (BET), photocurrent measurements, Mott-Schottky analysis, photoluminescence (PL), electrochemical impedance spectroscopy (EIS), and electron spin resonance (ESR), were utilized to analyze the synthesized materials. Among the synthesized nanocomposites, the 15 wt% Fe₂O₃/Bi₂O₃/TiO₂ (15FeBi/TiO₂) composite demonstrated exceptional photocatalytic efficiency, achieving 98 % SMZ degradation and a hydrogen production rate of 590.36 μmol/g·h. Experimental results, including scavenging tests and ESR findings, highlighted the crucial role of hydroxyl radicals (•OH) and superoxide radicals (•O₂−) in the photocatalytic process. Moreover, liquid chromatography-mass spectrometry (LC-MS) results proposed three degradation pathways, and quantitative structure-activity relationship (QSAR) analysis showed that the toxicity of intermediates was effectively reduced. The 15FeBi/TiO₂ photocatalyst also exhibited excellent reusability, retaining about 85 % of its initial activity after five cycles, and proved effective against various pollutants and in real water matrices. This research contributes to the design and development of high-activity heterojunction photocatalysts for superior clean energy generation and pollutant degradation under visible light.

Customizing Bonding Affinity with Multi-Intermediates via Interfacial Electron Capture to Boost Hydrogen Evolution in Alkaline Water Electrolysis.

Developing efficient and earth-abundant alkaline HER electrocatalysts is pivotal for sustainable energy, but co-regulating its intricate multi-step process, encompassing water dissociation, OH- desorption, and hydrogen generation, is still a great challenge. Herein, we tackle these obstacles by fabricating a vertically integrated electrode featuring a nanosheet array with prominent dual-nitride metallic heterostructures characterized by impeccable lattice matching and excellent conductivity, functioning as a multi-purpose catalyst to fine-tune the bonding affinity with alkaline HER intermediates. Detailed structural characterization and theoretical calculation elucidate that charge redistribution at the heterointerface creates electron-accumulating W-W sites, which reduces the O p-W d and H s-W d interactions vs. single nitride, thereby enhancing OH- transfer and H2 release. As anticipated, the resulting WN-NiN/CFP catalyst demonstrates a gratifying low overpotential of 36.8 mV at 10 mA/cm² for alkaline HER, while concurrently maintainingoperational stability for 1300 h at 100 mA/cm² for overall water splitting. This work presents an effective approach to meticulously optimize multiple site-intermediate interactions in alkaline HER, laying the foundation for efficient energy conversion.

Modified Titanium Dioxide Nanoparticles for Photocatalytic Splitting of Water and Its Application in Environmental Remediation as a Potential Alternative

Herein we reviewed Titanium dioxide (TiO2) nanoparticles and how they are applied in the photocatalytic splitting of water to generate hydrogen but also to remove both organic and inorganic pollutants. Hydrogen generation through the splitting of water by TiO2 which is a cheap, efficient, and non-toxic photocatalyst has found wide application in clean energy production. The efficiency of the photocatalyst can be improved by using water or sacrificial agents as electron donors, thereby enhancing hydrogen production. In addition, this review explores the fundamental principles, mechanisms, and applications of TiO2-based photocatalysis. It further, highlights the structural properties, bandgap engineering, and surface modifications that influence the catalytic activity of TiO2. Additionally, we discuss the doping of TiO2 with both metals and non-metals to narrow the energy band gap which lowers the recombination effects. Finally, it introduces the potential applications of TiO2-based photocatalysis in the photodegradation of organic and inorganic pollutants.

Nanoflower-like NiCoFe layered hydroxide by in-situ electrochemical corrosion as highly efficient electrocatalyst for water oxidation

Layered double hydroxides have been widely applied for oxygen evolution reaction (OER) in the alkaline water electrolysis. However, the issues of poor connection between the catalyst and nickel foam and the specific mechanisms for active sites has not been fully documented. In this study, the in-situ nickel foam etching in a mixed solution of ferric chloride and cobalt nitrate at low temperatures was adopted for NiCoFe layered ternary hydroxides (NiCoFe LTHs) synthesis with a better tight integration. Physicochemical characterization indicated that the NiCoFe LTHs could grow directly through corroding nickel foam with a nano-flower-like morphology and structures. That is favorable for electron transfer from the catalytic layer to the conductive substrate. With the transition metal ions interaction and the tight integration construction, NiCo1Fe4-LTH-T60/NF presented an enhanced electrolysis performance with the overpotential of 234 mV (1.464 V vs. RHE) at current density of 100 mA cm−2 in 1 M KOH electrolyte. The Tafel slope for NiCo1Fe4-LTH-T60/NF electrode was 36.19 mV dec−1 for an enhanced OER kinetics. Besides, it demonstrated faster interfacial charge transfer process, better intrinsic electrochemical activity and stability in large current stability testing. It was revealed that the synergistic effect of the transition metal ions interaction enhancement and the mechanism of oxygen evolution elementary reaction for NiCo1Fe4-LTH-T60/NF during the water electrolysis by the electrochemical and theoretical calculation. This work provides theoretical basis and experimental support for the design and synthesis of future OER catalyst and substrate, which is significant for hydrogen and oxygen generation from water electrolysis.

“There is plenty of energy at the bottom”: A spectral conversion approach for upconversion-powered water-splitting PEC cell

An avant-garde step towards the use of the long infrared tail of the incident solar radiation with untapped and crucial applications in photocatalysis and energy harvesting schemes is presented: “there is plenty of energy at the bottom”. In detail, a pure photonic approach to enhance titanium dioxide (TiO2) photocatalytic activity is proposed, by using rare-earth doped luminescent glassy materials, capable of performing NIR-to-UV-VIS spectral conversion (up-conversion). Therefore we report infrared-driven boosting of green hydrogen production in a photo-electrochemical water-splitting cell using TiO2 electrodes, revisiting the original design of Fujishima and Honda fifty years later. This proof-of-concept comprises infrared-induced hydrogen and oxygen evolution via water-splitting and determines univocally the role of a solely photonic effect to split water. Thus, the conversion of the incident NIR radiation, before its interaction with the photocatalyst, emerges as a significant contribution to the state-of-the-art for an effective harvest of the near-infrared portions of sunlight.

Creating an intermediate energy band to boost the photoelectrochemical efficiency of TiO2 for solar-driven hydrogen production

The utilization of photoelectrochemical processes for hydrogen generation from water and solar energy offers a promising avenue to replace non-renewable energy sources. Nevertheless, achieving high-performance photoanode electrodes poses a significant challenge. In this study, we present the synthesis cerium and chromium-doped TiO2 (CeCrTiO2) is produced through a simple, scalable, and cost-effective hydrothermal method on a fluorine-doped tin oxide (FTO) substrate. the introduction of Ce and Cr impurities is highlighted for its role in creating an impurity band within CeCrTiO2. This impurity band is instrumental in enhancing the separation and movement of electrons and holes, contributing to the improved performance of CeCrTiO2 as a photoanode in photoelectrochemical applications. Hence, the photocurrent density value of CeCrTiO2 is 4.5 times higher than that of bare TiO2. This suggests that CeCrTiO2 exhibits improved efficiency in generating a photocurrent when exposed to light, indicating enhanced photoelectrochemical performance. The amount of hydrogen produced by CeCrTiO2 is noted to be 4.88 times greater than that of bare TiO2. This highlights the material's effectiveness in harnessing solar energy to drive the water-splitting reaction, leading to a higher yield of hydrogen gas. The synthesis of CeCrTiO2 through a hydrothermal method results in a photoanode with significantly enhanced performance, positioning it as a promising candidate for advancing photoelectrochemical processes aimed at replacing non-renewable energy sources.

Incorporation of (Cyclometalated-Ir)-Pt in Ultrastable Covalent Organic Frameworks for Enhanced Photocatalytic Hydrogen Production and Nitro Reduction

Incorporation of (Cyclometalated-Ir)-Pt in Ultrastable Covalent Organic Frameworks for Enhanced Photocatalytic Hydrogen Production and Nitro Reduction

Heterogeneous oxide/sulfide materials as superior bifunctional electrocatalysts for carbon-neutral green hydrogen production: A short review

Heterogeneous oxide/sulfide materials as superior bifunctional electrocatalysts for carbon-neutral green hydrogen production: A short review

Reaction kinetics and product evolution of hydrolysis in copper-chlorine thermochemical cycle for hydrogen production

By-products of the hydrolysis reaction in the copper-chlorine thermochemical cycle for hydrogen production are key to the final thermal and hydrogen efficiency. The current study focuses on the influences of reaction time, temperature, and steam partial pressure on the hydrolysis reaction and by-product formation mechanism via experimental and multiple analytical methods. The result demonstrates that the hydrolysis reaction of CuCl2 and steam converts to CuCl and Cu2OCl2, with a high conversion of 97%, while the Cu2OCl2 and CuCl2-CuO product mixtures exhibit interconversion capabilities. The increase of temperature increases the CuCl product content, while the decrease of steam partial pressure increases the by-product CuCl2. Particle morphology and reaction thermodynamics are analyzed for main and by-products formation. Finally, the homogeneous reaction model and shrinking core model are used and compared for the activation energy of the formation of Cu2OCl2 for the hydrolysis reaction and the effect of by-products.

A Comprehensive Technical, Environmental, Economic, and Bibliometric Assessment of Hydrogen Production Through Biomass Gasification, Including Global and Brazilian Potentials

A Comprehensive Technical, Environmental, Economic, and Bibliometric Assessment of Hydrogen Production Through Biomass Gasification, Including Global and Brazilian Potentials

Assessing electronic structure modulation strategies toward the development of low‐cost oxygen evolution reaction catalysts

AbstractOxygen evolution reactions (OER) are critical to electrochemical synthesis reactions, including hydrogen production and organic hydrogenation. However, the high cost of existing OER catalysts (primarily Ir/Ru and its derived oxides) limits their practical application for electrochemical synthesis. To develop a low‐cost, high‐efficiency alternative, we need a deeper understanding of both the mechanisms that drive OER and the relationship between the catalyst's electronic structure and active sites. Here, we summarized recent developments of catalysts, especially focusing on the electronic structure modulation strategies and their subsequent activity enhancement. Most importantly, we pointed out the study directions for further work.

Synthesis of Ecofriendly Bimetallic Pt/Ni Nanoparticles on KNbO3 via Hydrothermal Process for Sustainable Hydrogen Evolution from NaBH4

The performance of nickel and platinum bimetallic nanoparticles (NPs) supported on potassium niobate (KNbO3) is evaluated in the catalytic hydrolysis of sodium borohydride (NaBH4) to generate hydrogen (H2). KNbO3 was synthesized via a hydrothermal route using Nb2O5 and KOH as precursors. X-ray diffraction (XRD) confirmed the crystalline orthorhombic structure of KNbO3. The Ni/Pt NPs, with an average size of 4.66 nm and a spherical morphology, were uniformly dispersed on the surface of KNbO3 nanosheets. The N2 physisorption isotherms of KNbO3 and Ni/Pt NPs were classified as type V with H3 hysteresis, showing specific surface areas of 0.170 and 2.87 m2 g−1, respectively. Catalytic performance studies examined various Ni/Pt molar ratios, with the 1:3 ratio (mol/mol) demonstrating the highest efficiency. Kinetic analysis of NaBH4 hydrolysis showed that the data fit the pseudo-first-order model. An increase in temperature enhanced the hydrogen generation rate (HGR), reaching 2068.3 mL gcat−1 min−1 at 315.05 K. The apparent activation energy (Ea) was determined to be 29.9 kJ mol−1. Durability assays showed only an 11% decrease in activity after 11 catalytic cycles. Thus, a promising, easy-to-synthesize, and environmentally friendly catalyst for NaBH4 hydrolysis has been developed.

Iron (Magnetite) Nanoparticle-Assisted Dark Fermentation Process for Continuous Hydrogen Production from Rice Straw Hydrolysate

The use of metal nanoparticles (NPs) to enhance hydrogen production in dark fermentation (DF) has become a pioneering field of interest. In particular, iron-based nanoparticles (FeNPs) play a pivotal role in enhancing the activity of metalloenzymes and optimizing feedstock utilization, resulting in improved hydrogen production. This study investigated the effect of FeNPs (magnetite) supplementation at three different concentrations of 50, 100, and 200 ppm in a continuous dark fermenter for the production of hydrogen from rice straw acid hydrolysate. The highest hydrogen production rate of 2.6 ± 0.3 NL H2/L-d was achieved with the addition of 100 ppm of nanoparticles, representing a 53% increase compared to the condition without FeNPs addition. This improvement was driven by a microbial community in which Clostridium was the major dominant genus. In addition, increasing the nanoparticle concentration to 100 ppm resulted in an increase in butyrate concentration to 2.0 ± 0.1 g/L, which is 43% higher than the butyrate concentration without FeNPs. However, when the NP concentration was increased to 200 ppm, the hydrogen production rate decreased to 1.6 ± 0.2 NL H2/L-d. This study can serve as a guideline for future research aimed at evaluating the effects of FeNPs in continuous dark fermentation systems. This work highlights the potential benefits and challenges associated with the use of FeNPs, paving the way for future studies to optimize their application and improve the efficiency of dark fermentation processes.

High-Performance Composite Membranes: Embedding Yttria-Stabilized Zirconia in Polyphenylene Sulfide Fabric for Enhanced Alkaline Water Electrolysis Efficiency.

Due to their excellent alkali resistance and chemical stability, polyphenylene sulfide (PPS) fabric membranes are widely used in alkaline water electrolysis (AWE) for hydrogen production. However, traditional PPS membranes suffer from poor hydrophilicity, low airtightness, and high area resistance, resulting in high energy consumption and reduced safety in industrial applications. This study addresses the aforementioned issues by coupling 3-(2,3-epoxy propoxy) propyl trimethoxy silane (KH560) via self-condensation to the PPS membrane and blending it with self-synthesized yttrium-stabilized zirconia nanoparticles (YSZNPs). The YSZNPs are loaded onto the modified PPS fiber surface through dip-coating and hot-pressing processes, forming a micro-mechanical interlocking structure that enhances the overall performance of the membrane in practical hydrogen production applications. The findings indicate that the developed composite membrane demonstrate outstanding hydrophilicity, minimal area resistance (0.21 Ω cm2), and elevated bubble point pressure (2.93224bar). Significantly, tests on gas purity indicate that the produced hydrogen and oxygen attain purities of 99.90% and 99.75%, respectively, when evaluated at a current density of 1.5 A cm-2. Moreover, after 500h of electrolysis testing in a simulated industrial environment, minimal decline in membrane performance is observed, highlighting the competitive edge of this composite membrane in the current AWE market.