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1.
《International Journal of Hydrogen Energy》2022,47(100):41956-41973
Due to stringent environmental regulations and the limited resources of fossil-based fuels, there is an urgent demand for clean and eco-friendly energy conversion devices. These criteria appear to be met by hydrogen proton exchange membrane fuel cells (PEMFCs). PEMFCs have attracted tremendous attention on account of their excellent performance with tunable operability and good portability. Nonetheless, their practical applications are hugely influenced by the scarcity and high cost of platinum (Pt) used as electrocatalysts at both cathode and anode. Pt is also susceptible to easy catalyst poisoning. Herein, this paper reviews the progress of the research regarding the development of electrocatalysts practically used in hydrogen PEMFCs, where the corner-stone reactions are cathodic oxygen reduction reaction (ORR) and anodic hydrogen oxidation reaction (HOR). To reduce the costs of PEMFCs, lessening or eliminating the use of Pt is of prime importance. For current and forthcoming laboratory/large-scale PEMFCs, there is much interest in developing substitute catalysts based on cheaper materials. As such are non-platinum (non-Pt), non-platinum group metals (non-PGMs), metal oxides, and non-metal electrocatalysts. Hence, high-performance, state-of-the-art, and novel structured electrocatalysts as replacements for Pt are needed. 相似文献
2.
《International Journal of Hydrogen Energy》2022,47(6):3550-3555
Electrocatalytic nitrogen reduction reaction (ENRR) offers a carbon-neutral process to fix nitrogen into ammonia, but its feasibility depends on the development of highly efficient electrocatalysts. Herein, we report that Fe ion grafted on MoO3 nanorods synthesized by an impregnation technique can efficiently enhance the electron harvesting ability and the selectivity of H+ during the NRR process in neutral electrolyte. In 0.1 M Na2SO4 solution, the electrocatalyst exhibited a remarkable NRR activity with an NH3 yield of 9.66 μg h?1 mg?1cat and a Faradaic efficiency (FE) of 13.1%, far outperforming the ungrafted MnO3. Density functional theory calculations revealed that the Fe sites are major activation centers along the alternating pathway. 相似文献
3.
《International Journal of Hydrogen Energy》2022,47(10):6710-6720
Herein, molybdenum disulfide nanoflakes decorated copper phthalocyanine microrods (CuPc-MoS2) are synthesized via two step simple hydrothermal method. The as synthesized hybrid along with pure molybdenum disulfide (MoS2) nanoflower and pure copper phthalocyanine (CuPc) microrods are well characterized by various techniques that confirm phase, morphology, elemental compositions etc. Next, electrocatalytic oxygen reduction reaction towards fuel cell is investigated in alkaline medium and obtained results proclaim that our CuPc-MoS2 heterostructure outperforms the other two constituent materials. Efficient oxygen reduction is achieved following four electron pathway by CuPc-MoS2 whereas partial reduction is done through two electron process by CuPc and MoS2 separately. Long-time durability test reveals almost 97.6% retention after 8000s that eventually dictate us that CuPc-MoS2 heterostructure can be the efficient cathode electrocatalyst for future generation fuel cell. 相似文献
4.
《International Journal of Hydrogen Energy》2022,47(65):28074-28085
In this paper, a new carbon support with a large number of mesoporous-structures is selected to prepare Pt/C catalysts. Transmission electron microscope (TEM) results show that the Pt/3# catalyst presents a sponge-like morphology, Pt particles are not only evenly distributed on the surface of carbon support, but also the smaller Pt particles are deposited in the mesoporous inside the support. The average diameter of Pt particles is only 2.8 nm. The membrane electrode assembly (MEA) based on Pt/3# catalyst also shows excellent performance. In conclusion, the 3# support is an idea carbon support for PEMFC, which helps to improve the oxygen reduction reaction (ORR) activity of the catalyst. Based on the “internal-Pt” structure of the support mesoporous, the efficient three-phase boundaries (TPBs) are construct to avoid the poisoning effect of ionomer on the nano-metal particles, reduce the activation impedance and oxygen mass transfer impedance, and improve the reaction efficiency. 相似文献
5.
Pengfei Chen Honggang Chang Tao Peng Yongfan Tang Youquan Liu Chao Xiang 《应用聚合物科学杂志》2021,138(30):50314
Hydraulic fracturing with slickwater is a field-proven stimulation technology used in tight reservoirs. Because of the high pumping rate associated with slickwater fracturing, drag reduction (DR) is critical in minimizing pressure drop and the success of oilfield operations. In this paper, a new type of drag reducer (SPR) was synthesized with acrylamide and 12-allyloxydodecyl acid sodium, and its drag reduction performance was evaluated. The results showed that the new drag reducer features low molecular weight, fast-dissolving rate and low interfacial tension. The algorithm of estimating the drag reduction rate of non-Newtonian fluid SPR was proposed and validated. Empirical or semianalytical models for estimating the friction ratio (σ) or friction factor (λ or f) were used to simulate the turbulence behavior of the SPR drag reducer under different Reynolds numbers (Re). The modified Virk's correlation could accurately model the turbulent behavior of the SPR drag reducer. A unified calculation formula was established in this study for different pipe diameters. 相似文献
6.
《International Journal of Hydrogen Energy》2022,47(4):2279-2292
A new catalyst for both water reduction and oxidation, based on an infinite chain, {[Ni(tn)2]3 [Fe(CN)4 (μ-CN)2]2}n, is formed by the reaction of NiCl2, 1,3-propanediamine (tn) and K3 [Fe(CN)6]. {[Ni(tn)2]3 [Fe(CN)4 (μ-CN)2]2}n can electro-catalyze hydrogen evolution from a neutral aqueous buffer (pH 7.0) with a turnover frequency (TOF) of 1561 mol of hydrogen per mole of catalyst per hour (H2/mol catalyst/h) at an overpotential (OP) of 837 mV {[Ni(tn)2]3 [Fe(CN)4 (μ-CN)2]2}n also can electro-catalyze O2 production from water with a TOF of ~45 mol O2 (mol cat)?1s?1 at an OP of 591 mV. Under blue light (λ = 469 nm), together with CdS nanorods (CdS NRs) as a photosensitizer, and ascorbic acid (H2A) as a sacrificial electron donor, {[Ni(tn)2]3 [Fe(CN)4 (μ-CN)2]2}n can photo-catalyze hydrogen generation from an aqueous buffer (pH 4.0) with a turnover number (TON) of 11,450 mol H2 per mole of catalyst (mol of H2 (mol of cat)?1) during 10 h irradiation. The average of apparent quantum yield (AQY) is as high as 40.96% during 10 h irradiation. Studies indicate that {[Ni(tn)2]3 [Fe(CN)4 (μ-CN)2]2}n exists in two forms: a cyano-bridged chain ({[Ni(tn)2]3 [Fe(CN)4 (μ-CN)2]2}n) in solid, and a salt ([Ni(tn)2]3 [Fe(CN)6]2) in aqueous media; Catalytic reaction occurs on the nickel center of [Ni(tn)2]2+, and the introduction of [Fe(CN)6]3- can improve the catalytic efficiency of [Ni(tn)2]2+ for H2 or O2 generation. We hope these findings can afford a new method for the design of catalysts for both water reduction and oxidation. 相似文献
7.
8.
《International Journal of Hydrogen Energy》2022,47(54):22981-22992
In this study, a three-dimensional model was established using the lattice Boltzmann method (LBM) to study the internal ice melting process of the gas diffusion layer (GDL) of the proton exchange membrane fuel cell (PEMFC). The single-point second-order curved boundary condition was adopted. The effects of GDL carbon fiber number, growth slope of the number of carbon fibers and carbon fiber diameter on ice melting were studied. The results were revealed that the temperature in the middle and lower part of the gradient distribution GDL is significantly higher than that of the no-gradient GDL. With the increase of the growth slope of the number of carbon fiber, the temperature and melting rate gradually increase, and the position of the solid-liquid interface gradually decreases. The decrease in the number of carbon fibers has a similar effect as the increase in the growth slope of the number of carbon fibers. In addition, as the diameter of the carbon fiber increases, the position of the solid-liquid interface gradually decreases first and then increases. 相似文献
9.
William M. Pitts Martin Werrel Marco Fernandez Mary A. Long Evan A. Eisenberg James Filliben Cory D. Runyon 《火与材料》2021,45(1):127-154
Fire spread and growth on real‐scale four cushion mock‐ups of residential upholstered furniture (RUF) were investigated with the goal of identifying whether changes in five classes of materials (barrier, flexible polyurethane foam, polyester fiber wrap, upholstery fabric, and sewing thread), referred to as factors, resulted in statistically significant changes in burning behavior. A fractional factorial experimental design plus practical considerations yielded a test matrix with 20 material combinations. Experiments were repeated a minimum of two times. Measurements included fire spread rates derived from video recordings and heat release rates (HRRs). A total of 13 experimental parameters (3 based on the videos and 10 on the HRR results), referred to as responses, characterized the measurements. Statistical analyses based on Main Effects Plots (main effects) and Block Plots (main effects and factor interactions) were used. The results showed that three of the factors resulted in statistically significant effects on varying numbers of the 13 responses. The Barrier and Fabric factors had the strongest main effects with roughly comparable magnitudes. Foam was statistically significant for fewer of the responses and its overall strength was weaker than for Barrier and Fabric. No statistically significant main effects were identified for Wrap or Thread. Multiple two‐term interactions between factors were identified as being statistically significant. The Barrier*Fabric interaction resulted in the highest number of and strongest statistically significant effects. The existence of two‐term interactions means that it will be necessary to consider their effects in approaches designed to predict the burning behavior of RUF. 相似文献
10.
《International Journal of Hydrogen Energy》2022,47(87):36831-36842
Two electron oxygen reduction reaction to produce hydrogen peroxide (H2O2) is a promising alternative technique to the multistep and high energy consumption anthraquinone process. Herein, Ni–Fe layered double hydroxide (NiFe-LDH) has been firstly demonstrated as an efficient bifunctional catalyst to prepare H2O2 by electrochemical oxygen reduction (2e? ORR) and oxygen evolution reaction (OER). Significantly, the NiFe-LDH catalyst possesses a high faraday efficiency of 88.75% for H2O2 preparation in alkaline media. Moreover, the NiFe-LDH catalyst exhibits excellent OER electrocatalytic property with small overpotential of 210 mV at 10 mA cm?2 and high stability in 1 M KOH solution. On this basis, a new reactor has been designed to electrolyze oxygen and generate hydrogen peroxide. Under the ultra-low cell voltage of 1 V, the H2O2 yield reaches to 47.62 mmol gcat?1 h?1. In order to evaluate the application potential of the bifunctional NiFe-LDH catalyst for H2O2 preparation, a 1.5 V dry battery has been used as the power supply, and the output of H2O2 reaches to 83.90 mmol gcat?1 h?1. The excellent electrocatalytic properties of 2e? ORR and OER make NiFe-LDH a promising bifunctional electrocatalyst for future commercialization. Moreover, the well-designed 2e? ORR-OER reactor provides a new strategy for portable production of H2O2. 相似文献