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1.
An on-site laboratory with direct access to cleaned and conditioned steel mill gases was recently put into operation. The long-term performance and stability of Clariant's MegaMax®800 methanol synthesis catalyst utilizing steel mill gases is currently being investigated. First test results revealed that in order to investigate deactivation mechanisms arising from particular properties of the cleaned steel mill gases, the overlaying effect of thermal deactivation of the catalyst has to be minimized. 相似文献
2.
《Ceramics International》2021,47(24):34828-34835
In this paper, potassium titanate whiskers was prepared via the Molten salt synthesis on the surface of cordierite ceramics for the regeneration of diesel particulate filters (DPFs). SEM, EDS, XRD, FT-IR, TG-DSC and TPO were carried out to characterize the morphology, microstructure, growth mechanism and catalytic performance of the samples. Potassium titanate whiskers with diameter (100–500 nm) and length (about 3 μm) is tightly combined with the cordierite ceramic substrate. The catalyst performance investigation demonstrates that potassium titanate whiskers decrease the soot combustion temperature apparently. The soot combustion process was studied by thermal analysis tests, and the activation energy of the combustion reaction can be calculated using Freeman-Carroll method. The carbon oxidation activation energy is 14.009 kcal/mol, and the activation energy for the catalytic reaction with potassium titanate whiskers is 6.287 kcal/mol, it can be illustrated that potassium titanate whiskers/cordierite catalyst possess excellence performance for carbon catalytic combustion. The coarseness of the interface increased because potassium titanate whiskers grew on the cordierite substrate, and the trapping ability could improve. This unique microstructure has potential application in the DPF field. 相似文献
3.
《International Journal of Hydrogen Energy》2022,47(57):23994-24003
Hydrogenation of dibenzyltoluene (DBT) is of great significance for the application in liquid organic hydrogen carriers (LOHCs). We successfully develop Mg-based metal hydrides (Mg2NiH4, MgH2, and LaH3) reactive ball-milling for the hydrogenation of DBT. Mg-based metal hydrides milled with 500 min exhibit the best catalytic activity, the hydrogen uptake of DBT can reach 4.63 wt% at the first 4 h and finally achieve 5.70 wt% through 20 h, which is the first time to use hydrogen storage material as a catalyst for the hydrogenation of DBT. The excellent catalytic hydrogenation performance of Mg-based metal hydrides mostly originates from numerous catalytic activity centers formed at the surfaces of Mg2NiH4 nanoparticles in the MgH2 matrix. Inspired by this mechanism, more general metal hydrides can be explored for catalyzing the hydrogenation of LOHCs. The new application of Mg-based metal hydrides is beneficial to developing efficient LOHC based hydrogen storage systems and offers novel insights to hydride-based catalysts. 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.
《International Journal of Hydrogen Energy》2022,47(94):39961-39972
Micro-cracks commonly occur on the catalyst layers (CLs) during the manufacturing of catalyst coated membranes (CCMs). However, the crack shape parameters effect on CLs in-plane (IP) electronic conductivity λs is not clear. In this work, the relationship between crack parameters and the λs is obtained based on the two-dimensional (2D) multiple-relaxation time (MRT) lattice Boltzmann method (LBM). The LBM numerical model is validated by the normalized λs experiment applied on three different home-made cracked CLs, and the parameter study focus on crack width, length, quantity and phase angle are carried out. The results show that the decrease of λs has different sensitivity |k| to the parameters above. The crack width has little effect on λs decrease, and the |kw| is 0.038. However, crack arm length and quantity show more significant impact, which |kl| and |kN| are 0.753 and 0.725, respectively. The CLs with different crack propagation directions show significant anisotropy on λs, and a 53.53% decrease in λs is observed between 0° and 90° crack phase angle change. To manufacture a high electronic conductivity CL, crack initiation and migration mitigation are highly encouraged. 相似文献
6.
《International Journal of Hydrogen Energy》2022,47(12):7836-7845
Catalyst samples for CH4 decomposition were prepared from red mud (RM) by an acid-leaching neutralization precipitation approach. Water-washing the resultant precipitates multiple times, followed by drying at 105 °C and calcination at 500 °C, resulted in a threshold of residual Na2O, equivalent to 96% Na2O removal. Drying the precipitate at a higher temperature of 200 °C, followed by repeated water washing, provided a deeper Na2O removal of 99% and made the resultant samples more active for the targeted reaction. Subsequently, four catalyst samples with a simulated red mud composition and NaOH contents from 0 to 0.3 wt% were prepared and the catalytic test results revealed that the Na2O remaining in the RM-derived catalysts did not only inhibit their activation in CH4 but also lower their maximal activities for CH4 decomposition. Finally, two catalysts with the same simulated red mud composition and their Na impregnated respectively on Fe2O3 and a mixture support of Al2O3-SiO2-TiO2 were prepared and tested to explore the effect of Na distribution on the activation behavior of RM-derived catalysts for CH4 decomposition. The activity testing results showed that it was the Na residual dispersed on iron oxides in the RM-derived samples to significantly inhibit the activation of CH4 decomposition. 相似文献
7.
Jun Wang Hongpeng Li Xi Chen Weiguang Shi Na Zhang Fuquan Bai Xiaofeng Wang Sihan Wang Xianming Xu Libo Wang 《中国化学工程学报》2019,27(11):2687-2695
The BF3/n-BuOH complexes were investigated as active species in catalyzing n-decene polymerization reaction. The structures of BF3/n-BuOH complexes were characterized not only by modern spectrum but also by calculation at theoretical level. The results confirmed that BF3/n-BuOH complexes changed from BF3·(n-BuOH)2 complexes to BF3·n-BuOH complexes with the mass fraction of BF3 increasing. These two complexes have different catalytic activity, but BF3·n-BuOH was superior. The highest n-decene conversion could reach 99% and the most excellent selectivity of n-decene trimer and tetramer could reach up to 80% yield by a series of controlled conditions. This work can help to understand the catalytic active species of n-decene polymerization and provide support for industrialization of poly-alpha-olefins (PAOs). 相似文献
8.
Ruiyuan Zhang Ting Min Yan Liu Li Chen Wen-Quan Tao 《International Journal of Hydrogen Energy》2021,46(38):20037-20053
Reducing the Platinum (Pt) loading while maintaining the performance is highly desired for promoting the commercial use of proton exchange membrane fuel cells (PEMFCs). Different methods have been adopted to fabricate catalyst layers (CLs) with low Pt loading, including utilizing lower Pt/C catalysts (MA), mixing high Pt/C catalysts with bare carbon black particles (MB), and reducing CL thickness while maintaining high Pt/C ratio (MC). In this study, self-developed pore-scale model is adopted to investigate the performance of the three Pt reduction methods. It is found that MA shows the best performance while MB shows the worst. Then, effects of Pt dispersion are further explored. The results show that denser Pt sites will result in higher local oxygen flux and thus higher local transport resistance. Therefore, MA method, which shows the better Pt dispersion, leads to improved performance. Third, CLs with quasi-realistic structures are investigated. Higher tortuosity resulting from the random pores produces higher bulk resistance along the thickness direction, while MA still exhibits the best performance. Finally, improved CL structures are investigated by designing perforated CL structures. It is found that adding perforations can significantly reduce the bulk transport resistance and can improve the CL performance. It is demonstrated that CL structure plays important roles on performance, and there are still huge potentials to further improve CL performance by increasing Pt dispersion and optimizing CL structures. 相似文献
9.
Jiajia Lu Guangfu Qian Lin Luo Huibing He Shibin Yin 《International Journal of Hydrogen Energy》2021,46(1):676-682
The tungsten trioxide attracts less attention due to the low electron transfer kinetics that hinders the interaction of electrons and ions during the hydrogen evolution reaction (HER). But the oxygen vacancy strategy can inspire its electrocatalytic activity for HER because it has a positive effect on improving the charge transfer and compensating for the weak hydrogen adsorption of the tungsten trioxide. By synthesizing a series of substoichiometric tungsten oxides, we reveal the linear relationship between the catalytic activity and the content of oxygen vacancies, which indicates that the oxygen vacancy strategy is an achievable route to enhance the HER for metal oxides. 相似文献
10.
Mahsa Varmazyari Yasin Khani Farzad Bahadoran Zahra Shariatinia Saeed Soltanali 《International Journal of Hydrogen Energy》2021,46(1):565-580
Cu(BDC) metal–organic framework (MOF) was used as a support for the copper (Cu) catalyst applied in the methanol steam reforming (MSR) process at low temperatures (130–250 °C) with a feed WHSV = 9.2 h?1 within the monolithic reactor. Also, the effects of diverse promoters were examined on the catalytic activities of the Cu/X–Cu(BDC) (X = Ce, Zn, Gd, Sm, La, Y, Pr) catalysts. Results showed that the Ce/Sm–Cu(BDC) supports exhibited highest activities, lowest reduction temperatures and largest specific surface areas, which caused highest distributions of the active copper metal nanoparticles on the supports. The reactor tests displayed that the activities of Cu/X–Cu(BDC) (X = Ce, Zn, Gd, Sm, La, Y, Pr) catalysts followed the order X = Ce > Sm > Y > La > Pr > Cu(BDC) > Zn > Gd. The highest activities of Ce and Sm containing catalysts were attributed to the presence of CeO2 and Sm2O3 caused the oxygen vacancies on the catalyst surface which had positive effects on the methanol reforming process. The time-on-stream stability tests showed the highest resistance of the Cu/Ce–Cu(BDC) catalyst to the carbon formation during 32 h. Consequently, the Cu/Ce–Cu(BDC) with the highest stability, methanol conversion and carbon monoxide selectivity could be used in practical industrial applications. 相似文献