Lei HUANG,Zhi-hui YANG,LÜ-ji YAN,Sikpaam Issaka ALHASSAN,Hai-yin GANG,Ting WANG,Hai-ying WANG
2D carbon ribbon/Al 2 O 3 was synthesized with two-dimensional metal organic frameworks 2D-MOFs as precursors using the solvothermal and calcination methods. Batch experiments of adsorption parameters such as pH, liquid/solid ratio, adsorption kinetics, adsorption thermodynamics, and anions competitions were investigated to understand the adsorptive behavior of fluoride on carbon ribbon/Al 2 O 3 and nitrogen-doped carbon ribbon/Al 2 O 3 . The adsorption of fluoride on carbon ribbon/Al 2 O 3 could be described as the chemical and multilayer adsorption, while the adsorption of fluoride on nitrogen-doped carbon ribbon/Al 2 O 3 followed the chemical and monolayer adsorption phenomenon. The fluoride on nitrogen-doped carbon ribbon/Al 2 O 3 had a much faster adsorption rate of 3.1×10 −7 m/s than carbon ribbon/Al 2 O 3 , which was 1.2×10 −7 m/s. The nitrogen-doping on carbon ribbon enhances structural defects and improves the adsorption performance of fluoride. Also, the diacetylene linkages (—C≡C—) and pyridinic-N were studied to understand their influences on removing fluoride. The result indicates that carbon ribbon and nitrogen-doped ribbon could serve as good adsorbents for removing fluoride.
Jiajia Chen,Baobao Bai,Juan Lei,Peng Wang,Shuang Wang,Jinping Li
Mn 3 O 4 catalysts have shown great potentials for toluene catalytic oxidation for the spinel structure and weak metal oxygen bonds. In this work, Mn 3 O 4 and Mn 2 O 3 catalysts were obtained by using Mn-MOFs with different ligands as precursors. It was found that the reduction of hydroxyl groups in 2,5-dihydroxyterephthalic acid was favorable for the preparation of Mn 3 O 4 under the proper temperature range. The Mn 3 O 4 -MOF-74–300 catalyst exposed the highest Mn 3+ , O ads /O latt and reducing capacity. Herein, the Mn 3 O 4 -MOFs-74–300 catalyst exhibited excellent performance for toluene oxidation, which could achieve 90% toluene conversion at 218 ℃ (toluene concentration = 1000 ppm and SV = 20000 mL·g −1 ·h −1 ). Moreover, the Mn 3 O 4 -MOFs-74–300 catalyst exhibited high stability, circulation performance and water resistance in the catalytic test.
The catalytic hydrogenation of aromatic nitro compounds under mild conditions to generate amino compounds is a great challenge in terms of conversion, selectivity and stability. In this paper, two classes of nitrogen-doped carbon coated nickel nanoparticles, coined Ni@NC-P and displaced Ni@NC-T were prepared by high-temperature pyrolysis of MOFs using inexpensive terephthalic acid and high-priced trimesic acid as carbon source, respectively. One from the former class, namely the Ni@NC-P-500 catalyst, exhibits the best catalytic performance, which is superior to Ni@NC-T-500 Samples. For the selective hydrogenation of p -nitrophenol under mild conditions (60 °C, 2 h), the Ni@NC-P-500 catalyst shows >99.9 % conversion of p -nitrophenol and >99.9 % selectivity for p -aminophenol and can be recycled five times without obvious decrease of conversion and selectivity, thanks to its larger specific surface area (382.02 m 2 ·g −1 ), smaller nickel particle size (8.2 nm), higher nitrogen content (especially pyridine nitrogen), higher electron-rich nickel content and less hydrophilic properties than that of the Ni@NC-T-500. The excellent stability and recyclability of the catalysts are mainly attributed to their core–shell structure, i.e., zero-valent nickel nanoparticles encapsulated within a nitrogen-doped carbon layer with an appropriate microporous structure, whereas zero-valent nickel nanoparticles have the ability to activate dihydrogen and block dioxygen.
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