Hydrogen Production In Reactor Research Articles

Hollow Mo/MoSVn Nanoreactors with Tunable Built-in Electric Fields for Sustainable Hydrogen Production.

Constructing built-in electric field (BIEF) in heterojunction catalyst is an effective way to optimize adsorption/desorption of reaction intermediates, while its precise tailor to achieve efficient bifunctional electrocatalysis remains great challenge. Herein, the hollow Mo/MoSVn nanoreactors with tunable BIEFs are elaborately prepared to simultaneously promote hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) for sustainable hydrogen production. The BIEF induced by sulfur vacancies can be modulated from 0.79 to 0.57 to 0.42mV nm-1, and exhibits a parabola-shaped relationship with HER and UOR activities, the Mo/MoSV1 nanoreactor with moderate BIEF presents the best bifunctional activity. Theoretical calculations reveal that the moderate BIEF can evidently facilitate the hydrogen adsorption/desorption in the HER and the breakage of N─H bond in the UOR. The electrolyzer assembled with Mo/MoSV1 delivers a cell voltage of 1.49V at 100mA cm-2, which is 437mV lower than that of traditional water electrolysis, and also presents excellent durability at 200mA cm-2 for 200h. Life cycle assessment indicates the HER||UOR system possesses notable superiority across various environment impact and energy consumption. This work can provide theoretical and experimental direction on the rational design of advanced materials for energy-saving and eco-friendly hydrogen production.

Hierarchical Architectures by Hybridizing Ru Nanoparticles with Nitrogen/Oxygen Dual‐Doped Carbon Nanotubes for Advanced Hydrogen Evolution Reaction Performance

AbstractDeveloping highly efficient and stable electrocatalysts is critical for advancing hydrogen evolution reactions (HER) for hydrogen production. Herein, we report a facile approach to fabricating a hierarchical catalyst featuring ruthenium (Ru) nanoparticles uniformly integrated with nitrogen/oxygen co‐doped carbon nanotube aerogels (Ru‐NOCAs). Heteroatoms N and O‐modified CNTs can result in a negatively charged surface to effectively trap Ru3+ ions. Ru‐NOCAs exhibit a well‐defined hierarchical morphology facilitated by the self‐assembly of functional groups on the surface of CNTs, which enhances the interaction between Ru nanoparticles and CNTs. Due to the synergistic effect of hierarchical structure and strong interaction formation, Ru‐NOCAs show excellent catalytic activity and stability. Ru‐NOCAs catalyst demonstrates a remarkable overpotential of 41 mV at 10 mA cm−2 with a Tafel slope of 57 mV dec−1 in 1 M KOH and an overpotential of 68 mV with a Tafel slope of 65.8 mV dec−1 in 0.5 M H2SO4. These results indicate superior catalytic efficiency and enhanced charge transfer kinetics compared to the control samples. This study highlights the effectiveness of incorporating hierarchical structures and tailored surface chemistries in electrocatalyst design, offering new avenues for optimizing HER performance and advancing hydrogen fuel technology.

In-situ development of highly active Ni-Cu-P@Co-Se as active and stable electrode for energy-saving hydrogen production and urea oxidation reaction

Here, a simple two-step method for synthesizing of unique, active and stable Ni-Cu-P@Co-Se electrocatalyst is introduced. The fabricated electrode demonstrated favorable performance in application as electrocatalyst for hydrogen evolution reaction (HER) processes. When the current density increased from 5 to 10 mA.cm−2, the η10 decreased from 157 to 94 mV which indicated 40 % improvement in catalytic activity. In addition, the deposited electrode at 10 mA.cm−2 demonstrated best UOR performance which needed only 1.323 V vs RHE at 10 mA.cm−2, due to having high electrochemical active area, interfacial engineering, and the optimized interaction between the electrode and the electrolyte. When the Ni-Cu-P@Co-Se electrode was used as a bi-functional electrode in the urea electrolysis process, the cell potential value was 1.413 V. The synthesized electrode presented slight changes in overpotential during stability test. This work introduces an economical and effective method for the synthesis of active electrodes in energy-saving hydrogen production systems.

A 2D/3D hierarchical hybrid enables energy-saving hydrogen production coupled with glycerol and urea electro-oxidation

The design and development of high-performance electrocatalysts is crucial to improve the utility of anodic reaction for energy-saving hydrogen production. Herein, we present a novel catalyst with 2D/3D multistage structure for the electro-oxidation of renewable biomass and harmful waste to assist hydrogen generation. The hierarchical configuration of NiO/CoO nanosheets interconnected by hollow carbon spheres, leveraging both 2D and 3D advantages. This structure provides rich surface and edge active sites as well as affluent electron and mass transfer pathways, resulting in the accelerated dynamics of electro-oxidation. The hollow carbon spheres serve as a buffering agent to alleviate the strain caused by repetitive redox reactions during electrolysis, thereby bestowing exceptional structural and chemical stability for prolonged operational durability. Additionally, the multiple continuous hetero-interfaces between NiO and CoO, NiO and carbon as well as CoO and carbon can ensure the fast electron transport, leading to the expedited reaction kinetics with the synergistic effect of phase engineering between NiO, CoO and carbon shell. As a result, the 3D carbon shells jointed 2D NiO/CoO hybrids demonstrate promising catalytic activities on electro-oxidation for energy-efficient hydrogen production (∼100 %FE) coupled with urea oxidation and formic acid synthesis with excellent selectivity (95.40 %) and satisfied faradic efficiency (91.6 %).

Different surfaces of copper with single-atom doping for hydrogen evolution reaction in alkaline conditions

The advantages of Cu-based materials make it a potential catalyst for alkaline hydrogen production reactions (HER), but the inertness of pure Cu restricts its application. Thus, it is very meaningful to seek strategies to improve the catalytic activity. In this work, we designed the 15 modified Cu surface models by integrating single atom doping with surface engineering to be used to explore the catalytic activity of Cu surfaces in alkaline HER and the mechanism of effective adsorption and dissociation of water. The results indicated that the combination of surface engineering with single-atom doping can greatly activate the electro-catalysis activity of copper surface. All these 15 catalysts can effectively achieve hydrogen evolution in alkaline conditions, among which the H2O dissociation energy barriers of Cu(210)-Os and Cu(210)-Ru are just 0.47 eV and 0.60 eV, which are much lower than that of pure Pt(111). Thus, it is expected that Cu(210) doped with proper noble metal elements is an ultra-low-cost and ultra1-high-performance catalyst for alkaline HER. Meanwhile, Os and Ru-doped Cu(110) and Cu(211) surfaces also demonstrate remarkable alkaline HER activity compared with the metal catalysts that have been reported hitherto. These offer a novel concept and theoretical guidance to design cheaper and more efficient HER catalysts.

Quantitative evaluation of leakage flow rate in the sealing part using graphite gland packing to mount a hydrogen separation membrane tube for HI decomposition membrane reaction

The thermal efficiency of hydrogen production in the thermochemical iodine-sulfur (or sulfur-iodine) can be effectively enhanced using a membrane reactor for the HI decomposition reaction (about 500 °C) for hydrogen production. The attachment of ceramic tubes, made of brittle materials, for hydrogen separation membranes to a tube plate via sealing parts is a critical aspect of this process. A quantitative procedure was specified to make an expanded graphite grand packing exhibit sealing performance. The applicability of the method was tested during 50 thermal cycles ranging between 25°C-450 °C and gas pressure of 0.3–0.9 MPa. The leakage flow rate using a dummy membrane tube and helium gas (a tracer gas) was approximately 2 × 10−5 Pa m3 s−1. This value is comparable to the detection limit of the standard bubble leak test, indicating the effectiveness of this sealing procedure. Furthermore, the leakage flow rate was proportional to the differential pressure applied to the sealing part, suggesting a molecular flow type. This allows for estimating the leakage flow rate by introducing the conductance of flow paths, formulated based on the molecular kinetic theory of gases. An estimation method of the leakage flow rate at any packing size and any pressure difference is proposed, which can help design future practical membrane reactors.

Modulating electronic density of active metal site via MXene intercalated by alkali ions for superior hydrogen production

As the core of a catalyst, the active site plays a crucial role in determining the activity and selectivity in hydrogen production reactions. Herein, the size and surface electron density of bimetallic alloy nanoparticles (NPs) were engineered by (alkali ions)-intercalated-Ti3C2Tx MXene, in which alkali ions were removed by water after the intercalation of Ti3C2Tx. The intercalation of alkali ions can effectively increase the interlayer spacing of Ti3C2Tx, enhance the surface accessibility, and improve the interaction between active metal species and Ti3C2Tx, resulting in monodisperse, ultrafine, and surface electron-rich active metal NPs. Resultantly, the obtained NiPt/(Li+)-Ti3C2Tx exhibits an exceptional catalytic performance with a turnover frequency (TOF) value of 3200 h−1 toward complete dehydrogenation of N2H4·H2O at 323 K, which is about 43 and 4-times higher than that of pristine NiPt NPs (75 h−1) and them on Ti3C2Tx without alkali ions intercalation (787 h−1), respectively, and surpassing all the reported catalysts for this dehydrogenation reaction. Additionally, this catalyst also shows an ultrahigh catalytic performance (7317 h−1) for complete dehydrogenation of N2H4BH3 under the same reaction conditions. This work for the first time found that the more electrons on the surface of the active center, the better the activity for hydrazine decomposition, providing inspiration for regulating catalytic active sites and designing efficient heterogeneous catalysts to achieve nitrogen-based hydride activation.

Heterostructuring Uniform 2D CdS on Ru/Ti3C2-TiO2 via In situ Oxidized Ru-Loaded MXene for Boosting Photocatalytic H2 Production.

Building heterojunctions and exposing more catalytic active sites are effective strategies to enhance the photocatalytic hydrogen evolution activity. Herein, TiO2 nanosheets are oxidized in situ on Ru-loaded MXene as carriers and subsequently loaded with uniform 2D CdS via hydrothermal method to obtain 2D Ru/Ti3C2-TiO2/CdS composite photocatalysts that integrate heterojunctions and cocatalysts. The formation of heterojunction between CdS and TiO2 is conducive to promoting the separation and transfer of photogenerated charges, simultaneously, Ru/Ti3C2 with the fully exposed Ru and Ti3C2 can act as effective active sites of photocatalytic hydrogen production reaction. The composite photocatalyst exhibits an improved hydrogen production rate with 5479µmol g-1 h-1, which is 5, 3, and four times more than that of pristine CdS, CdS loaded Ti3C2-TiO2and CdS loaded Ru-TiO2 respectively. The results reveal that the notable enhancement in performance can primarily be ascribed to the introduction of the TiO2/CdS heterojunction and the efficient cocatalysts of Ru/Ti3C2. Moreover, the 2D Ti3C2 with high conductivity as carriers can increase charge transfer, and its 2D structure can serve as a template for growing 2D photocatalysts with higher activity. The interface engineering with multiple interfaces can offer novel insights for the advancement of efficient hydrogen evolution reaction catalysts.

Performance of a pilot-scale microbial electrolysis cell coupled with biofilm-based reactor for household wastewater treatment: simultaneous pollutant removal and hydrogen production.

The septic tank is the most commonly used decentralized wastewater treatment systems for household wastewater treatment in on-site applications. The removal rate of various pollutants is lower in different septic tank configurations. The integration of a microbial electrolysis cells (MEC) into septic tank or biofilm-based reactors can be a green and sustainable technology for household wastewater treatment and energy production. In this study, a 50-L septic tank was converted into a 50-L MEC coupled with biofilm-based reactor for simultaneous household wastewater treatment and hydrogen production. The biofilm-based reactor was integrated by an anaerobic packed-bed biofilm reactor (APBBR) and an aerobic moving bed biofilm reactor (aeMBBR). The MEC/APBBR/aeMBBR was evaluated at different organic loading rates (OLRs) by applying voltage of 0.7 and 1.0V. Result showed that the increase of OLRs from 0.2 to 0.44kg COD/m3 d did not affect organic matter removals. Nutrient and solids removal decreased with increasing OLR up to 0.44kg COD/m3 d. Global removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), ammoniacal nitrogen (NH4+), total phosphorus (TP) and total suspended solids (TSS) removal ranged from 81 to 84%, 84 to 85%, 53 to 68%, 88 to 98%, 11 to 30% and 76 to 88% respectively, was obtained in this study. The current density generated in the MEC from 0 to 0.41 A/m2 contributed to an increase in hydrogen production and pollutants removal. The maximum volumetric hydrogen production rate obtained in the MEC was 0.007 L/L.d (0.072 L/d). The integration of the MEC into biofilm-based reactors applying a voltage of 1.0V generated different bioelectrochemical nitrogen and phosphorus transformations within the MEC, allowing a simultaneous denitrification-nitrification process with phosphorus removal.

Fe(III)-cycle enhanced carbon oxidation reaction for low-energy hydrogen production via water electrolysis

Integrating the hydrogen evolution reaction (HER) with the carbon oxidation reaction (COR) is a promising method for producing H₂ with lower energy consumption. However, due to the passivation effect of oxygen functional groups (OFGs) for COR and Fe³⁺, achieving efficient and sustainable carbon oxidation to assist water electrolysis for hydrogen production remains a challenge over the past decades. This study introduced [EDTA·Fe(III)]– as a mediator to promote COR. [EDTA·Fe(III)]– effectively prevented the oxidation layer on the carbon surface from anchoring Fe (III) and reactivated the carbon that had been passivated by the oxidation layer. Density functional theory calculations indicated that the notable COR activity resulted from [EDTA·Fe(III)]– effectively lowering the vertical ionization potential of carbon, without being affected by OFGs. Notably, in the HER||COR-[EDTA·Fe(III)]– system, a cell voltage of merely 0.74 V is sufficient to reach a current density of 10 mA cm−2, with the corresponding energy consumption being 1.76 kWh Nm−3 (H2). This strategy offers new insights into achieving stable, low-energy hydrogen production via water electrolysis.

Coupling Photocatalytic Hydrogen Production with Key Oxidation Reactions

AbstractHydrogen represents a clean and sustainable energy source with wide applications in fuel cells and hydrogen energy storage systems. Photocatalytic strategies emerge as a green and promising solution for hydrogen production, which still reveals several critical challenges in enhancing the efficiency and stability and improving the whole value. This review systematically elaborates on various coupling approaches for photocatalytic hydrogen production, aiming to improve both efficiency and value through different oxidation half‐reactions. Firstly, the fundamental mechanism is discussed for photocatalytic hydrogen production. Then, the advances, challenges, and opportunities are expanded for the coupling of photocatalytic hydrogen production, which focuses on the integration of value‐added reactions including O2 production, H2O2 production, biomass conversion, alcohol oxidation, and pollutants treatment. Finally, the challenges and outlook of photocatalytic H2 production technology are analyzed from the aspects of coupling hydrogen production value, photocatalyst design and reaction system construction. This work presents a holistic view of the field, emphasizing the synergistic benefits of coupled reactions and their practical application potential, rather than focusing on catalysts or single reaction systems. This review provides valuable references for the development and application of photocatalytic hydrogen production in energy conversion and environmental conservation through sustainable, eco‐friendly and economic pathways.

Coupling Photocatalytic Hydrogen Production with Key Oxidation Reactions.

Hydrogen represents a clean and sustainable energy source with wide applications in fuel cells and hydrogen energy storage systems. Photocatalytic strategies emerge as a green and promising solution for hydrogen production, which still reveals several critical challenges in enhancing the efficiency and stability and improving the whole value. This review systematically elaborates on various coupling approaches for photocatalytic hydrogen production, aiming to improve both efficiency and value through different oxidation half-reactions. Firstly, the fundamental mechanism is discussed for photocatalytic hydrogen production. Then, the advances, challenges, and opportunities are expanded for the coupling of photocatalytic hydrogen production, which focuses on the integration of value-added reactions including O2 production, H2O2 production, biomass conversion, alcohol oxidation, and pollutants treatment. Finally, the challenges and outlook of photocatalytic H2 production technology are analyzed from the aspects of coupling hydrogen production value, photocatalyst design and reaction system construction. This work presents a holistic view of the field, emphasizing the synergistic benefits of coupled reactions and their practical application potential, rather than focusing on catalysts or single reaction systems. This review provides valuable references for the development and application of photocatalytic hydrogen production in energy conversion and environmental conservation through sustainable, eco-friendly and economic pathways.

Optimal pH condition for hydrogen production using δ-FeOOH under UV irradiation

δ-FeOOH was synthesized to produce hydrogen and its properties were investigated. Although δ-FeOOH has a band gap energy that absorbs sufficient visible light, it cannot produce hydrogen in the visible-light region. However, δ-FeOOH can successfully produce hydrogen under UV. These results indicate that the hydrogen production reaction with δ-FeOOH under UV irradiation is related to the photo-Fenton reaction. The hydrogen production ability was investigated by controlling the pH of the solution, which is an important factor in the photo-Fenton reaction. As the pH of the solution decreased, the amount of hydrogen produced increased. The crystal structures of δ-FeOOH before and after hydrogen production were compared, and it was confirmed that the two crystal structures were identical. This result represents that the photo-Fenton reaction is a circular reaction, and δ-FeOOH can produce hydrogen semi-permanently under UV.

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.

Experimental study of the design and performance optimisation of a self-heating methanol on-board reforming reactor for hydrogen production

There is an increasing research on efficient and compact on-board reformer, based on which a serpentine plate type self-heating reformer integrating preheating, reforming and combustion has been designed and fabricated, which can be disassembled and assembled flexibly. In this paper, experiments on the self-heating reformer have been carried out to optimise the differential structure of different chambers. It can be found that: the combustion chamber needs to be partitioned and the resistance loss is small and stable for a long time when the number of partitions is 3. The combustion chamber with O2/CH3OH = 1.5 has the highest wall temperature of 240 °C. Hydrogen yield can be increased to more than two times after optimising the evaporation chamber. The catalyst in the reforming chamber must be uniformly distributed, and the methanol conversion rate is stable at 75 % with a mass of 110 g and Weight Hourly Space Velocity (WHSV) = 8 h−1. The optimum operating conditions of the reactor is WHSV = 8 h−1 with air flow rate of 25 L/min, at which the reactor starts up within 20 min, the hydrogen yield stabilises within 40 min, and the hydrogen yield is 9.8 L/min and remains stable for 120 min.

Metal oxide/chalcogenide/hydroxide catalysts for water electrolysis

Electrochemical water electrolysis has gained rapid and significant interest from scientists and researchers in hydrogen production to reduce the dependency on fossil fuels and hydrogen culture recognition worldwide soon. However, developing highly efficient, economical, and durable electrocatalysts with the replacement of noble-metal-based catalysts is essential for the large-scale practical application of this strategy. Due to heightened interest in this field, a series of various bifunctional catalysts have been developed, and several articles have been published on overall water splitting (OWS). Herein, we studied an extensive kind of recent literature on designing novel metal oxide/chalcogenide/hydroxide catalysts electrocatalysts ranging from metal oxide/hydroxide and metal chalcogenides for water electrolysis. This includes the analysis of characteristics of oxygen and hydrogen evolution reactions (OER/HER) and OWS in basic, acidic, and neutral media and indices for evaluating the performance of electrocatalysts at first and then synthesis routes to obtain metal oxide/chalcogenide/hydroxide electrocatalysts are critically reviewed. Finally, the prospects of activation strategies to enhance the performance of electrocatalysts and activity descriptors are discussed. Moreover, this review will provide a route for constructing high-performance noble-metal-free electrocatalysts in sustainable water electrolysis reactions for hydrogen production.

Hybrid magnetic nanocomposite NiFe2O4/TiO2 for Photocatalytic dye degradation and green hydrogen (H2) generation

The present paper focuses on designing and developing nanocomposites to modify their properties to increase the ability to generate hydrogen and degrade photocatalytic dyes. A nanocomposite of nickel ferrite (NiFe2O4)/Titanium dioxide (TiO2) was formulated using the sol-gel self-ignition method. X-ray diffraction (XRD) tool was adopted to analyze the structural behavior of pure nickel ferrite (NiFe2O4), pure titanium dioxide (TiO2), and nanocomposite of NiFe2O4/TiO2. XRD pattern of NiFe2O4 and TiO2 shows a monophasic nature whereas the XRD pattern of nanocomposites shows mixed phases of NiFe2O4 and TiO2. FTIR spectra confirm the formation of NiFe2O4, TiO2, and their composites with absorption bands near 400 cm-1 and 600 cm-1, 1500 cm-1. Raman spectra unveiled the presence of five active Raman modes in the case of NiFe2O4 whereas three active Raman modes are seen in TiO2. Field emission scanning electron microscopy (FE-SEM) images exposed the dense structure with spherical cluster-like morphology in the case of NiFe2O4. Energy-dispersive X-ray spectroscopy (EDX) analysis confirms the presence of all the desired elements of NiFe2O4, TiO2, and their composites in stoichiometric proportions. BET analysis of nickel ferrite NPs suggests a large surface area of the order of 31.54 m2/gm in comparison with TiO2 (19.23 m2/gm). The optical characterization was made through the UV-visible spectroscopic technique. TiO2 shows a maximum band gap of the order of 3.02 eV while NiFe2O4 shows a low band gap of the order of 1.74 eV. A typical M-H curve with saturation magnetization of the order of 27.54 emu/gm was observed for pure NiFe2O4. No magnetic properties were observed for TiO2 as it is a semiconductor. Enhancement in magnetic properties is observed with increases in NiFe2O4 content in a composite of NiFe2O4/TiO2. The photocatalytic activities were examined by degrading Methylene Blue (MB) dye under sunlight for pure nickel ferrite (NiFe2O4), pure titanium dioxide (TiO2), and a nanocomposite of NiFe2O4/TiO2. Photocatalytic hydrogen production reactions were carried out in a methanol/water solution under visible light. Consequently, the best configuration of the photocatalyst was determined as 25% wt% NiFe2O4/ TiO2 which had shown the maximum hydrogen (H2) production rate as 146.3 μmol/g/h after 8 h owing to its reduced bandgap energy and delayed e- / h+ recombination.

Modulating local coordination structure over single Pt atom to optimize adsorption behavior for high-efficiency photocatalytic H2 production

The development of single-atom photocatalysts featuring precisely defined coordination structure is of great significance for elucidating the correlations between catalytic performances and coordination structures, yet it remains a grand challenge. Herein, the asymmetric/symmetric Pt-Nx moieties in carbon nitride (denoted as Pt-Nx@MCT, x equals to a coordination number of 3 or 4) are elaborately constructed by a coordination structure regulation strategy. The hydrogen production performances of Pt-N3@MCT and Pt-N4@MCT photocatalysts display a relationship with the Pt-N coordination numbers, with Pt-N3@MCT showing a photocatalytic activity (195 μmol h−1) 3 times that of Pt-N4@MCT (65 μmol h−1) and an apparent quantum yield of 34.1 % at 420 nm. The asymmetric Pt-N3 moiety in Pt-N3@MCT acts as electron collector to promote the separation and transfer of charge carriers and to create the higher occupied Pt d orbital, weakening the bond strength between hydrogen intermediates and Pt atomic sites and accelerating hydrogen production reaction kinetics in Pt-N3@MCT.

NiCoMn phosphides-based 3D nanoflowers as universal electrocatalyst towards hydrogen evolution reaction at all pH values

In addressing the pH constraints encountered in real-world electrolyte environments, it is of great practical significance to establish a universal electrocatalyst capable of facilitating the hydrogen production reaction (HER) across all pH levels. Herein, non-precious metals NiCoMn were incorporated into a nickel foam skeleton and subjected to phosphorization treatment, yielding the NiCoMn-O-P@NF catalyst suitable for HER across the entire pH spectrum. Leveraging the synergistic effects of these three metals and phosphating regulation, the synthesized NiCoMn-O-P@NF demonstrates efficient HER catalytic performance in acidic (−0.05 VRHE at 10 mA cm−2), alkaline (−0.17 VRHE at 10 mA cm−2), and neutral (−0.25 VRHE at 10 mA cm−2) electrolytes, with exceptional stability. This study presents a cost-effective electrocatalyst with robust and enduring catalytic performance for HER over the full pH range, offering an environmentally friendly solution to the challenges of practical hydrogen generation.

Modeling gas holdup in a multiphase oxygen slurry bubble column reactor for Cu-Cl hydrogen production using CFD

The hydrodynamics of the oxygen bubble column reactor is investigated numerically using CFD analyses to predict the values of the gas holdup using Eulerian model and k−ε turbulence method. It is shown that, at any given static liquid height and solid concentration, increasing the superficial gas velocity leads to a higher gas holdup. Also, the gas holdup reduces when the static liquid height increases and/or the solid concentration increases at any given superficial gas velocity. All gas holdup findings were verified by experimental results from prior literature, showing excellent agreement and validating the models' applicability to this kind of a slurry bubble column system. Profiles of gas holdup obtained from CFD simulations were shown to generally under-predict the experimental data. Also, it is shown that CFD models accurately anticipated the experimental effects of the superficial gas velocity, static liquid height, and solid concentration on gas holdup.