Di-Chang Zhong,Yue-Lei Mao,Xin Tan,Ping Zhong,Liang-Xian Liu
Chemical hydrogen storage, endowed with superiorities of safety and efficiency, has been regarded as one of the most promising approaches. The design and synthesis of metallic catalytic system is an key step for development of chemical hydrogen storate materials. In this paper, we report that RhNi nanocatalyst, formed by spontaneously alloying of well-dispersed Rh and Ni NPs , exhibits much higher performance in the catalytic dehydrogenation of hydrous hydrazine.
Manhong Liu,Qiang Bai,Hailian Xiao,Yanyan Liu,Jun Zhao,William W. Yu
Colloidal platinum–ruthenium bimetallic nanoparticles with 2.3 nm were synthesized in solution and then immobilized on tin dioxide powder to make a supported nanocatalyst (Pt–Ru/SnO 2 ). The immobilized bimetallic nanoparticles had the same size and size distribution as the solution dispersed ones. Selective hydrogenation of o -chloronitrobenzene to o -chloroaniline was performed over the as-prepared Pt–Ru/SnO 2 nanocatalyst without using any solvent; 99.5% selectivity to o -chloroaniline at ∼100% conversion was achieved.
Hong Zhang,Ming Chen,Tiantian Liang,Zanpeng Zhang,Changhui Yang
The use of nanocarbon materials to enhance the toughness of fragile cementitious materials has attracted increasing attention for investigation. This study examines the effects of incorporating graphene oxide (GO) into NaOH-activated slag (AAS) pastes and mortars, focusing on workability, phase composition, mechanical properties, and the local mechanical properties of the interfacial transition zone (ITZ) between sand and paste. The experimental results indicate that the addition of GO decreases the flowability of NaOH-AAS pastes, with noticeable aggregation at concentrations above 0.03 wt%. Furthermore, GO enhances the hydration degree of ground granulated blast furnace slag (GGBS), leading to an increased amount of C-A-S-H gel without introducing new phases. In terms of macro performance, incorporating 0.03 wt% GO significantly improves the compressive and flexural strengths of NaOH-AAS mortars by 10.6 % and 17.9 %, respectively. Additionally, the presence of GO reduces the ITZ thickness from 30 to 15 micrometres in NaOH-AAS mortars, which likely contributes to the enhanced mechanical performance.
Liuting Zhang,Farai Michael Nyahuma,Haoyu Zhang,Changshan Cheng,Jiaguang Zheng,Fuying Wu,Lixin Chen
Nb 2 O 5 nanoparticles with an average particle size of 10 nm supported on a rhombic dodecahedral metal organic framework (MOF) were successfully synthesized by a facile one-pot hydrothermal reaction and subsequent calcination process. Experimental results demonstrated that the prepared catalyst drastically improved the hydrogen storage behavior of MgH 2 . 7 wt% Nb 2 O 5 @MOF doped MgH 2 started to desorb hydrogen at 181.9 °C and 6.2 wt% hydrogen could be released within 2.6 min and 6.3 min at 275 °C and 250 °C, respectively. The fully dehydrogenated composite also displayed excellent hydrogenation by decreasing the onset absorption temperature to 25 °C and taking up 4.9 wt% and 6.5 wt% hydrogen within 6 min at 175 °C and 150 °C, respectively. Moreover, the corresponding activation energy was calculated to be 75.57 ± 4.16 kJ mol −1 for desorption reaction and 51.38 ± 1.09 kJ mol −1 for absorption reaction. After 20 cycles, 0.5 wt% hydrogen capacity was lost for the MgH 2 +7 wt% Nb 2 O 5 @MOF composite, much lower than 1.5 wt% of the MgH 2 +7 wt% Nb 2 O 5 composite. However, the addition of Nb 2 O 5 @MOF had limited effect on reducing the dehydrogenation enthalpy of MgH 2 . Microstructure analysis revealed that Nb 2 O 5 particles were uniformly distributed on surface of the MgH 2 matrix and synergistically improved the hydrogen storage property of MgH 2 with MOF.
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