International Journal of Hydrogen Energy最新文献

Monolithic catalyst is very important for the further industrial application of hydrogen production via NaBH₄ hydrolysis. Nowadays, the structural stability and catalytic performance of aerogel based monolithic catalysts still need to be further improved. Herein, the amorphous Ru–Co(OH)_x@GO particles are synthesized by in-situ growth and transformation of ZIF-67 on the surface of GO, the hydrogen generation rate and activation energy via catalytic NaBH₄ hydrolysis can reach 11,062 mL min⁻¹ g⁻¹ and 36.2 kJ mol⁻¹, respectively. Meanwhile, the composite aerogel of Ru–Co(OH)_x@GO, chitosan and carbonylated cellulose nanofiber is prepared by solution blending and freeze drying, and the hydrogen generation rate has 7680 mL min⁻¹ g⁻¹ (retained 69.4%) under the same amount of Ru–Co(OH)_x@GO. Furthermore, after high speed catalytic hydrogen generation, the aerogel can still maintain its structural integrity, thus facilitating recovery and reuse, which is attributed to the co-structural coupling of carbonylated cellulose nanofiber and chitosan macromolecule to the skeleton. This work provides a convenient and controllable strategy for the development of monolithic catalysts.

Although phosphoric acid-doped PBI holds great promise for application in high-temperature proton exchange membrane fuel cells, the stabilities of phosphoric acid-doped membranes are compromised due to the low absorption capacity of phosphoric acid, poor solubility and difficulty in processing. In this study, by introducing poly (5-phenyl-1H-1,2,3-triazole) monomers into the polybenzimidazole main chains, a semi-flexible polybenzimidazole (PBI-QP) was prepared. The mechanical properties of PBI-QP membranes were better than that of PBI membrane. The tensile strength of PBI-QP-20 reached to 130.9 MPa. Compared with PBI, the solubility of PBI-QP has improved significantly. PBI-QP can be easily dissolved in the solvents of DMF, DMSO and formic acid separately at room temperature. All the membranes exhibited super thermal stability. At 800 °C there is still 72% quantity of residue and the thermal stability of PBI-QP can meet the thermal stability requirements of HT-PEMFCs. The membranes of PBI-QP demonstrated high phosphoric acid absorption (ADL 10.5) and enhanced antioxidant properties. The proton conductivity is 64.3 mS∙cm⁻¹ at 170 °C and the peak power density attains an impressive level of 573.6 mW cm⁻² at 180 °C. The results indicate that the synthesized HT-PEMs exhibit excellent solubility and impressive peak power density, underscoring their substantial promise for utilization in HT-PEMs.

The hydrogen-diesel dual-fuel mode is an efficient way of lowering exhaust emissions from compression-ignition engines. Along with exhaust emissions, mechanical vibration and noise emissions are also problems for these engines. In dual fuel mode, it is possible to reduce all emissions by using the appropriate injection strategy. In this study, different injection strategies were used in an engine with an ECU-controlled liquid and gas fuel system. In experiments, constant load (5 Nm), constant speed (1850 rpm), constant hydrogen energy ratio (12%), 4 different hydrogen injection pressures (1, 1.5, 2.0, and 2.5 Bar), and 5 different hydrogen injection starts (25, 35, 45, 55, and 65 °CA aTDC) were performed. In the study, exhaust, mechanical vibration, and noise emissions were recorded and analysed. When a few of the study's data were looked at, it was determined that CO₂ emissions decreased by 33.4% and PM emissions by 40.7% at 25 °CA aTDC injection start and 2.5 bar injection pressure. Under the same experimental conditions, NO emissions increased by 8.7%, mechanical vibration emissions increased by 19.9%, and noise emissions increased by 2 dBA.

Power to Methane (PtM) systems are considered an attractive alternative for power generation, renewable sources’ potential harnessing, and atmospheric carbon dioxide (CO₂) utilization. This study analyzes the potential use of Synthetic Natural Gas (SNG) for electrical power generation or its direct injection into the currently available Natural Gas Transportation infrastructure. A simulation approach using Aspen Plus v14 software was employed to assess various PtM configurations. Six different systems were analyzed for methanation processes, utilizing three types of electrolysis systems: Alkaline (AE), Proton Exchange Membrane (PEME), and Solid Oxide (SOE). Two primary methane applications were considered: integrated into a combined cycle for power generation and a standalone gas treatment stage for grid injection. As a result, the PEME-based system showed the highest generated-to-fed power ratio, larger than SOE (1.45% higher) and AE (20.66% higher). In addition, PEME technology reports the largest generation of SNG per power supply, exceeding 3.4% and 16.4% of those of SOE and AE, respectively. However, the SOE technology showed a larger efficiency than PEME technology by 8.2% and a PtM efficiency larger than PEME by 12.4%. Fixed capital investment for the PtM systems is around 8.6 and 13.9 million USD$, and their total earnings are between −8.2 and 20.9 thousand USD$ a year, depending on the electrolysis technology, methane application, and carbon credits scenario. According to these results, the PEME-based system is the most suitable option regarding technical and economic criteria.

Developing high-temperature hydrogen (H₂) sensors with fast response speed is urgently demanded in harsh application environments, especially for chemical industries and the aerospace field. Herein, we have reported a facile strategy to synthesize Mn-doped In₂O₃ hollow nanotubes (Mn-In₂O₃) by solvothermal and annealing route using In-MOFs as precursors. The experimental results indicate that the obtained products possess hollow nanotube structures with plenty of holes and Mn doping greatly boosts the gas-sensing performance of In₂O₃-based sensors towards H₂. In particular, the responses of 3 mol% Mn-In₂O₃ are 2.57 and 2.3 towards 50 ppm H₂ at 360 °C and 400 °C, respectively, which are much higher than those of bare In₂O₃ hollow nanotubes. Besides, the sensor based on 3 mol% Mn-In₂O₃ exhibits a low limit of detection (25 ppb), excellent selectivity, rapid response/recovery speed (∼4 and ∼15 s@20 ppm), and excellent stability at high temperature (360 °C). Such enhancement of H₂-sensing properties can be put down to the hollow structure derived from In-MOFs and abundant oxygen vacancy defects produced by Mn doping. The Mn-In₂O₃ hollow nanotubes could be regarded as promising materials for selectively detecting H₂ in a wide range of concentrations.

In this paper, CeMg₁₂/Ni/Nb₂O₅ was prepared by mechanical ball milling technology for the sake of probing into the impact of Ni and Nb₂O₅ on microstructure and hydrogen sorption properties of alloys. The microstructure research results indicate that adding Nb₂O₅ can promote the formation of nanocrystal structure; through ball milling the Nb₂O₅ dispersed on the surface of alloy particles uniformly enhances the surface activity of the alloy and improves the hydrogen absorption and releasing kinetics of the alloy. The research on hydrogen absorption performance shows that the addition of Nb₂O₅ can significantly increase the hydrogen release platform pressure of the alloy hydride, the enthalpy value of hydrogen releasing process drops from 74.82 kJ/mol to 71.07 kJ/mol when the content of Nb₂O₅ is increased from 0 wt% to 9 wt%, the above qualitative and quantitative discussion further proves that Nb₂O₅ is beneficial for amending the thermodynamic stability of alloy hydride. Besides, adding Nb₂O₅ can remarkably reduce the hydrogen dissociation activation energy of experimental alloy hydride, ameliorating the dynamic performances of hydrogen release. The alloy with 9 wt% Nb₂O₅ has the smallest activation energy and the best performances of hydrogen release.

Hydrogen transfer leaks are one of the most important life-limiting faults in polymer electrolyte membrane fuel cells (PEMFCs). Hydrogen transfer leaks result in a reduction in the amount of oxygen available in the cathode (air) channel, with large leaks resulting in oxygen starvation and hydrogen emission. This paper aims to develop an adaptive extended Kalman filter (EKF) to estimate the unknown oxygen concentration, which is then used to infer hydrogen leaks. To this end, the paper first develops the lumped model of the fuel cell from a pseudo-2D model of a fuel cell. Next, a (non-adaptive) EKF is developed to estimate the fuel cell states under both normal and oxygen-starved conditions. The adaptive EKF is then implemented by adding the unknown hydrogen leak to the list of estimated states. Finally, the paper demonstrates the efficacy of the proposed adaptive EKF by using it to accurately estimate unknown hydrogen leaks in a high-fidelity virtual fuel cell under excessively noisy conditions.

It is well known that numerous operational, material and design variables act upon the performance of a plant-based microbial fuel cell which is an emerging sustainable and versatile energy device like hydrogen fuel cells. However, due to the high complexity of these bioelectrochemical systems, new solutions are required to optimize performance and uncover hidden relationships between dominant fuel cell variables. For this purpose, a database of 229 observations was created for plant-based microbial fuel cells (PMFCs) with 159 descriptor variables and a target variable (maximum power density) based on experimental results from 51 recent publications. Then, some machine learning solutions like principal component analysis (PCA), classification trees and SHapley Additive exPlanations (SHAP) analysis were applied. The PCA indicated mainly two routes involving low and high chemical oxygen demand (COD) towards high maximum power density which consists of the plant family, wastewater type, support media, construction design, separator type, anode and cathode electrodes and light source. SHAP analysis revealed that the most important factors for high performance are operating temperature, natural light, soil support medium, and constructed wetland design. Finally, the classification tree successfully demonstrated nine routes towards high maximum power density which exclude the use of graphite plate cathode electrodes.

The potential of hydrogen as an energy source has positioned hydrogen storage as a prominent research domain in the current era. Innovative perovskite compounds have emerged as a focal point for investigating hydrogen storage applications. In this study, we have investigated the RbXH₃ (X = Mg/Ca/Sr/Ba) perovskite hydrides by density functional theory (DFT). Our exploration encompasses the analysis of electronic structures, mechanical stability, elastic properties, and optical and thermoelectric response. The cubic crystal structures of RbXH₃ are revealed, with lattice constants of 4.13, 4.54, 4.82, and 5.17 Å for X = Mg, Ca, Sr, and Ba, respectively. Electronic structure calculations indicate ionic bonding with a wide bandgap reduced with increasing size of X. Mechanical stability, essential for meeting the Born stability criterion, is scrutinized, whereas Pugh criteria suggest a ductile and hard nature for these materials. Thermoelectric characteristics regarding electrical and thermal conductivity, Seebeck coefficient, and power factors are elaborated. The figure of merit emphasizes their suitability for thermoelectric devices. The Gravimetric ratios indicate the hydrogen storage capability, potentially contributing to various transportation and power applications.

The economy of the Russian Federation is aimed at developing a fuel and energy complex that uses environmentally friendly energy, which corresponds to the global trend of reducing emissions of harmful substances into the atmosphere during the production of various types of products. Decarbonization is one of the biggest challenges of modern society. To solve this problem, renewable energy sources are being actively introduced, as well as various types of fuel, the combustion of which produces a minimum content of emissions. Among them, we can highlight the fuel that has the greatest prospects; this is hydrogen, a fuel with the highest energy content, reaching a value of 120 MJ/kg. Unlike renewable energy sources, the practice of which in a number of countries has caused a crisis in the reliability of the energy system, hydrogen technologies make it possible to achieve the task of decarbonization with minimal impact on the environment at all stages: production, transportation, combustion, without compromising reliability. The main problems of mass introduction of hydrogen technologies are the difficulty in obtaining, transporting and storing hydrogen fuel. Following the signing of hydrogen strategies, most developed countries are considering using hydrogen as a vehicle fuel. Hydrogen transport, unlike electric transport, is not limited by range, but the high cost of hydrogen transport and the lack of refueling infrastructure hinder the development of this type of technology. Currently, the most common fuel cell system is FCV (fuel cell vehicle).

The article presents the concept of hydrogen refueling, taking into account different technologies for the production of hydrogen fuel. Hydrogen must be stored at a filling station at a pressure of 300–800 bar, in a gaseous or liquid state. An analysis of the cost of construction and subsequent operation of hydrogen filling stations revealed criteria for the economic efficiency of their implementation depending on the amount of fuel consumed and storage methods.