Yu Qin,Ping Chen,Jinzhao Duan,Junxing Han,Hui Lou,Xiaoming Zheng,Haiping Hong
Carbon nanofiber-supported molybdenum carbide catalysts (Mo2C/CNF) with different loadings were prepared by the carbothermal hydrogen reduction method. Characterizations with Raman, XRD, N2-TGA, SEM, TEM and HAADF-STEM confirmed that Mo2C nanoparticles were successfully supported on the carbon nanofibers. The optimal reaction conditions with model compounds on Mo2C/CNF had a conversion of 98.03% and yield of 95.26%. It is interesting to note that a low evaporation rate positions the Mo2C nanoparticles on the outside of the CNF due to the capillary effect and the Mo2C nanoparticles on the outside of the CNFs showed high catalytic activity compared to ones on the inside of the CNFs. The Mo2C/CNF catalyst was recycled 5 times without any apparent loss of catalytic activity. Catalytic performances of Mo2C/CNF, Mo2C/AC (activated carbon) and Mo2C/CNT (multi-walled carbon nanotubes) were examined using methyl palmitate and maize oil. The results showed that molybdenum carbide could be a potential substitute for noble metals in transformation of vegetable oils.
Bin Qin,Yifei Cai,Xiaoqing Si,Chun Li,Jian Cao,Weidong Fei,Junlei Qi
The practical application of lithium-sulfur (Li-S) batteries is impeded by the shuttle effect of intermediate polysulfides and the inherent sluggish kinetics. Herein, Mo 2 C nanocatalysts anchoring on holey graphene scaffold (Mo 2 C@HGr) is explored as a lightweight and ultrathin modified separator to conquer the above issues. The artificially customized holes on holey graphene sheets facilitate ionic transfer and electrolyte penetration, and further enhance the sulfur utilization under lean electrolyte conditions. The experimental results together with theoretic calculation demonstrate the favourable chemical adsorption ability of Mo 2 C sites that blocking the diffusion of LiPSs. Abundant triple-phase interfaces among Mo 2 C nanomediators, holey graphene and electrolyte boost the conversion kinetics of the intercepted LiPSs. As a result, the cell with Mo 2 C@HGr modified separator shows superior rate capability (836 mAh g −1 ) even at 5 C current with a negligible Mo 2 C@HGr loading of 0.08 mg cm −2 . Furthermore, ultrahigh areal capacity of 5.9 mAh cm −2 is still attained with high sulfur loading of 6 mg cm −2 under lean electrolyte operation (E/S = 5.6 µL mg −1 ). This design concept can be extended to other graphene based multifunctional nanocomposite toward the development of more practical Li-S batteries.
危险品化学品经营许可证（带存储）