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101.
《International Journal of Hydrogen Energy》2023,48(76):29518-29529
Platinum (Pt) is often used as anodic catalyst for direct methanol fuel cell (DMFC). However, platinum is difficult to achieve large-scale application because of its low stability and high cost. In this work, the electrocatalytic activity and stability of the Pt-based catalyst for methanol oxidation (MOR) are significantly improved by adding Ce and Ni to the catalyst. Additionally, the rare earth element-Pr (Dy) is also chosen to be added into the catalysts for comparison. A series of PtMNi (M = Ce, Pr, Dy) catalysts are prepared by impregnation and galvanic replacement reaction methods using carbon black as support. The electrocatalytic mass activity of PtCeNi/C, PtDyNi/C, PtPrNi/C and Pt/C is 3.92, 1.86, 1.69 and 0.8 A mgPt−1, respectively. The mass activity of these the above four catalysts after stability measurement is 3.14, 1.49, 1.27 and 0.72 A mgPt−1. Among them, PtCeNi/C has the highest catalytic activity. These as-prepared catalysts are also characterized by various analyzing techniques, such as TEM, HRTEM, XRD, XPS, ICP-OES, STEM, STEM-EDS elemental mapping and line-scanning etc. It shows that PtCeNi/C exhibits best catalytic activity (3.92 A mgPt−1) among the as-obtained catalysts, 4.9 times higher than that of commercial Pt/C (0.8 A mgPt−1). PtCeNi/C is also with excellent anti-CO poisoning ability. The outstanding catalytic performance of PtCeNi/C for the MOR is mainly attributable to uniform-sized PtCeNi nanoparticles, uniform Ni, Ce and Pt element distribution, and electron interaction among Pt-, Ni- and Ce-related species (electron transferring from Pt to CeO2). 相似文献
102.
《International Journal of Hydrogen Energy》2023,48(76):29759-29770
This paper presents a mathematical model in the biofilm phase and in the gas phase that has been successfully applied to investigate various aspects of the biofiltration process. The mixtures of volatile organic compounds (VOCs) are emitted from a wide range of industries, such as chemical, petrochemical, pharmaceutical, pulp paper mills, printing and paint workshops, etc. The objective of the present study is, presence of high n-propanol loading negatively affected the toluene removal; however, n-propanol removal was not affected by the presence of toluene and was effectively removed in the biofilter despite high toluene loadings. A model for toluene and n-propanol biofiltration could predict the cross-inhibition effect of n-propanol on toluene removal. Further, we studied the effects of many physical and biological parameters on model prediction. The mathematical equations (2.12)-(2.16) which are non-linear partial differential equations are solved by using the homotopy perturbation technique. Also, we derived the semi-analytical results for toluene and n -propanol concentrations for saturated and unsaturated kinetics. It is verified that the proposed solution is validated by comparing it with numerical solutions. 相似文献
103.
《International Journal of Hydrogen Energy》2023,48(77):29928-29941
This study proposes a multi-objective optimization approach to design a steam methane reforming (SMR) reactor and maximize the efficiency of the hydrogen production process. Out of 1782 possible variable combinations, only 50 iterations were performed, identifying three Pareto optimal that resulted in reactor size reductions of 50.53%, 35.56%, and 20.69%, respectively, compared to the reference reactor. The process efficiency for each optimal design varied slightly, with one achieving a 105.05% increase in efficiency, another remaining stable at 100.48%, and a third experiencing a slight decrease to 86.66% compared to the reference case. The results offer practical insights for planning an on-site distributed hydrogen production system, demonstrating that an increase in overall process efficiency can be achieved even with a reduced reactor size. This work is the first attempt to optimize a hydrogen production system by simultaneously considering overall process efficiency and SMR reactor design. 相似文献
104.
《International Journal of Hydrogen Energy》2023,48(76):29530-29541
Poly[2-(dimethylamino)ethyl methacrylate] cryogel beads were prepared under cryogenic conditions via free radical polymerization and used as a catalyst in the production hydrogen (H2) from NaBH4 by alcoholysis. The efficiency of the catalyst was investigated in the range of 0–40 °C by both methanolysis and ethylene glycolysis reactions, and its reuse was tested. Accordingly, it was observed that the methanolysis reaction was faster than the ethylene glycolysis reaction. When the hydrogen generation rate (HGR) values between 0 and 40 °C were compared, it was concluded that the methanolysis reaction rate increased from 1550 to 4800 mL.min−1g−1 and the ethylene glycolysis reaction rate increased from 923 to 3551 mL.min−1g−1. In the alcoholysis reaction catalyzed by PDMA cryogel beads, the activation energy was calculated as 19.34 and 22.77 kJ.mol−1 for the methanolysis and ethylene glycolysis reactions, respectively. After six repetitions, the catalyst activity was calculated over 50% for NaBH4 methanolysis and ethylene glycolysis. 相似文献
105.
《International Journal of Hydrogen Energy》2023,48(74):28882-28890
The sluggish kinetics of urea oxidation reaction (UOR) critically restrict the prevalence of direct urea fuel cell (DUFC), utilizing electrolyte containing urea/urine. In this work, the copper and nickel-based composite oxides are prepared by meticulously controlling the galvanic reaction of copper ion to metallic nickel and the high-temperature oxidation process. Based on a systematic electrochemical characterization of the catalyst, the as-fabricated nano-architectures are optimized toward UOR performance, showing a low potential of 1.39 V vs. RHE to drive 100 mA cm−2 in alkaline solution. The button-like DUFCs configuration of as-developed catalysts exhibits a maximum power density of 1.19 mW cm−2. Furthermore, the DUFCs assembled with bio-urine, including men, dogs, cats, and rats as electrolytes without further purification, show a similar voltage. These findings open up a direction to convert bio-waste into treasure. 相似文献
106.
《International Journal of Hydrogen Energy》2023,48(76):29738-29747
Fe–N–C catalysts with excellent performance regarding the oxygen reduction reaction (ORR) have aroused enormous interest in direct-formate fuel cells (DFFCs). However, their limited mass transfer ability, insufficient ORR active sites, and complex fabrication processes remain significant obstacles to the widespread application of Fe–N–C catalysts. Herein, we propose a simple hydrothermal-annealing method with agarose powders to synthesize a uniform spherical Fe–N–C catalyst (∼3 μm) with well-developed mesopores (Fe/rG@C/H-Agar-900). The resultant Fe/rG@C/H-Agar-900 catalyst possesses rich oxygen-containing functional groups and enhanced interconnected pores, which can significantly boost the content of catalytic sites and facilitate mass transport, resulting in a high content of active sites. In the meantime, the mesopore content of Fe/rG@C/H-Agar-900, which can facilitate the formation of the three-phase gas/electrolyte/catalyst interfaces, was optimized by varying the annealing temperature. As a result, the Fe/rG@C/H-Agar-900 demonstrates a half-wave potential of 0.91 V vs. RHE, nearly four-electron pathway selectivity, excellent durability, and excellent formate tolerance for ORR. Furthermore, when used as the air cathode in membrane-less DFFCs, the Fe/rG@C/H-Agar-900-based device exhibits a remarkable peak power density of 24.5 mW cm−2, significantly outperforming the 20 wt% commercial Pt/C. This research facilitates the synthesis of an advanced Fe–N–C catalyst and promotes the practical development of membrane-less DFFCs. 相似文献
107.
《International Journal of Hydrogen Energy》2023,48(74):28758-28768
Defect engineering is an effective method to tune electronic states, which can provide active sites for electrocatalytic reactions. Herein, a highly efficient sulfur-doped bimetallic hydroxyl oxide (FeCo/Vc-S) has been synthesized by a two-step hydrothermal reaction, which has the rich defective and amorphous phases. The low coordination number of Co in X-ray absorption fine structure (XAFS) analysis further confirms the Co center is the active center, while Fe plays a role in optimizing the electronic structure of active Co species. Meanwhile, abundant oxygen vacancies and metal defects are also found in the material, which greatly enhances the adsorption and desorption efficiency of × OOH. Moreover, density functional theory (DFT) shows that the addition of S atom alters the electron distribution of adjacent metal atoms, thus adjusting the electron distribution of the metal active site. These positive factors endow FeCo/Vc-S with excellent OER electrocatalytic performance, with an overpotential of only 255 mV and Tafel slope is 64.3 mV·dec−1 at a current density of 10 mA cm−2. This study provides a new route for the synthesis of bimetallic hydroxyl oxides, and also provides theoretical design for the identification of active centers and defection-rich catalysts. 相似文献
108.
《International Journal of Hydrogen Energy》2023,48(76):29542-29551
Developing efficient catalysts for formic acid decomposition has been studied extensively. Herein, the Au3Pd1 intermetallic compound is designed as a single atom catalyst for the dehydrogenation of formic acid. By using density functional theory calculations, the thermodynamic stability, electronic structure, and reaction mechanism for the Au3Pd1 catalyst are systematically investigated, and the surface charge polarization and atom-ordered arrangement were confirmed to play an important role in the efficient formic acid dehydrogenation. The special positively charged Pd single atom on the Au3Pd1 surface becomes the adsorption site of HCOO− and the reaction site for formic acid decomposition. The nearby Au sites suppress the C–O bond cleavage due to their weak interaction with CO1 and OH1. As a result, the HCOO− dehydrogenation pathway is predominant on the Pd single atomic sites and the CO formation is well inhibited. This intermetallic-based catalyst can be extended to other systems and provided general guidance for efficient catalyst design. 相似文献
109.
《International Journal of Hydrogen Energy》2023,48(76):29699-29723
The paper develops a statistical model for optimizing the Hydrogen-injected Natural gas (H-NG) high-pressure pipeline network. Gas hydrodynamic principles are utilized to construct the pipeline and compressor station model. The model developed is implemented on a pipeline grid that is supposed to carry Hydrogen as an energy carrier in a natural gas-carrying pipeline. The paper aims to optimize different objectives using ant colony optimization (ACO). The first objective includes a single objective optimization problem that evaluates the maximum permissible hydrogen amounts blended with natural gas (NG) for a set of pipeline constraints. We also evaluated the variations in operational variables on injecting Hydrogen into the natural gas pipeline networks at varying fractions. The study further develops a multi-objective optimization model that includes bi-objective and tri-objective problems and is optimized using ACO. Traditional studies have focused on single-objective optimization with minimal bi-objective issues. In addition, none of the earlier research has shown the effect of introducing Hydrogen to the NG network using tri-objective function evaluations. The bi-objective and tri-objective functions help evaluate the effect of injecting Hydrogen on different operational parameters. The study further attempts to fill the gap by detailing the modelling equations implemented through a bi-objective and tri-objective function for the H-NG pipeline network and optimized through ACO. Pareto fronts that show the tradeoff between the different objectives for the multi-objective problem have been generated. The primary objective of the bi-objective and tri-objective optimization problems is maximizing hydrogen mole percent in natural gas. The other objective chosen is minimizing compressor fuel consumption and maximizing delivery pressure, throughput, and power delivered at the delivery station. The findings will serve as a roadmap for pipeline operators interested in repurposing natural gas pipeline networks to transport hydrogen and natural gas blend (H-NG) and seeking to reduce carbon intensity per unit of energy-delivered fuel. 相似文献
110.
《International Journal of Hydrogen Energy》2023,48(76):29682-29698
Sodium borohydride NaBH4 (SB) has been rediscovered in the late 1990s and been presented as a promising hydrogen storage material owing to its high gravimetric hydrogen density of 10.8 wt% and ability to produce H2 by hydrolysis at ambient conditions. This looked promising, but soon hydrolysis of SB encountered numerous obstacles. In 2015, a progress report (Int J Hydrogen Energy 2015; 40:2673–91) showed that the 2000–2014 research did not overcome all of the obstacles, making SB far from being technologically mature. Eight years have passed since 2015. Have we put more effort into all aspects relating to hydrolysis of SB? If so, do we have produced scaled-up technologies and prototypes, of which we would have a better knowledge? Have we been able to gain in technological readiness level? Answering these questions is the main objective of this article. A secondary objective is to summarize the newly acquired knowledge. Five main observations stand out. First, the 2015–2022 period is regrettably similar to the 2000–2014 since, again, catalysts have dominated the field and the other aspects (e.g. recycling of the by-product to regenerate SB, scale-up and implementation) have received little attention. Second, hydrolysis of SB still runs into numerous obstacles, some of the obstacles being known since a long time and other ones being relatively new and unknown. Third, there has been little gain in terms of technological readiness level while few research groups have shown that there is room for new ideas and innovation. Fourth, energy, exergy and economic analyses are needed to evaluate the overall cost of H2 from SB. Fifth, SB has not effectively thought from the end user perspective. In conclusion, many obstacles remain to be overcome before hydrolysis of SB can be a commercial solution for carrying and producing H2. However, all efforts should be dedicated to (i) construct, operate and optimize H2 production systems (i.e. prototypes and demonstrators), (ii) handle SB at the gram-to-kilogram scale, (iii) make production of SB even more efficient, and (iv) overcome all obstacles while thinking from the end user perspective. 相似文献