Wenzhi Li,Lihong Gao,Zhuang Ma,Yanbo Liu,Fuchi Wang,Jiawei Wang,Lijun Wang,Hezhang Li
Faced with the challenge of high energy ablation problems, especially for laser ablation , effective energy dissipation protective materials fabricate by efficient preparation method is a feasible solution. The Ni-graphite/SiO 2 coatings with different Ni content were prepared by plasma spraying method with optimized plasma spraying parameters. All coatings are pure without oxidation and dense. Their ablation behaviors were investigated by high power continuous wave laser. The results indicate that the Ni-graphite/SiO 2 coating with appropriate Ni content could realize the purpose of energy consumption by endothermal reaction of graphite/SiO 2 and reflection improvement. High Ni content will block the occurrence of endothermal reaction of graphite/SiO 2 and increase the heat diffusion to interior part of coating, which can make the ablation situation of coating more serious.
This work shows that PANI-SnO 2 nanorods with unique morphology and fine distribution of Pd-Ni alloy nanoparticles exhibit superior electrocatalytic performance toward methanol oxidation reaction (MOR). The amount of Ni content in Pd x -Ni y /PANI-SnO 2 nanorods plays a key role in Pd utilization. Ni in Pd x -Ni y /PANI-SnO 2 catalyst significantly reduces the CO adsorption on the active catalyst surface and enhances the electrode kinetics . The Pd 3 Ni 1 /PANI-SnO 2 composite exhibits high mass activity (1861.9 mA mg −1 ) with extended stability even after 10000 cycles (∼90% retention) compared to other Pd x Ni y counterparts, Pd/PANI-SnO 2 , and commercial Pd/C catalysts. Interestingly, adding Ni along with SnO 2 improves the electronic effect of Pd metal, significantly enhancing its catalyst activity and stability. Based on the results, we hope the present work brings an innovative approach to constructing efficient and cost-effective electrocatalysts for electrooxidation methanol in an alkaline medium.
The ceramics were prepared using the solid-state reaction method and their phase, microstructure and microwave dielectric properties were investigated. A single-phase clinoenstatite system with monoclinic structure (space group P2 1 /c) was confirmed through x-ray diffraction (XRD) analysis for the compositions with x ≤ 0.1. The compositions with x ≥ 0.15 contain SiO 2 and (Mg 1− x
Ni
x
) 2 SiO 4 phases only as confirmed from the XRD data of their sintered samples. The unit cell volume was decreased while the theoretical density was increased with increase in x from 0 to 0.1. A decrease in dielectric constant ( ε
r ) while an increase in unloaded quality factor multiplying the resonant frequency ( Q
u
f
o ) and temperature coefficient of resonant frequency ( τ
f ) was observed with increase in Ni content from 0 to x = 0.1. In the present study, ε
r ∼ 6.10, Q
u
f
o ∼ 118,702 GHz and τ
f ∼ −10 ppm/°C was achieved for the composition with x = 0.1 sintered at 1425°C for 9 h. The material is a good candidate for millimeter wave applications.
Xiaodong Li,Yanli Huang,Qian Zhang,Zhijun Zuo,Xiaodong Wang,Vladimir A. Vinokurov,Zheng Wang,Wei Huang
Ni-MoCeZr-MgAl(O) mixed oxide catalysts were successfully prepared from the Ce, Zr and Mo promoted hydrotalcite-like compounds (HTLcs) precursors using the simple and effective hexamethylenetetramine(HMT)-assisted hydrothermal synthesis method by tuning the molar ratio of n(HMT)/n(NO 3 − ). The influence of Ni content (3, 4.8, 6, 9 and 12%) on the catalytic performance of these catalysts in dry reforming of methane (DRM) was focused. Adjusting the content of Ni was able to change the metal dispersion and metal particle size, and small-sized (around 7 nm) and evenly dispersed Ni particles were obtained at Ni content of 6%. The catalyst with 6% Ni loading stood out for the high activity and stability, the CH 4 conversion of which fluctuated around 95% continuously for 610 h under GHSV of 60,000 mL·g cat −1 ·h −1 , and it was still above 92.8% throughout the 36-h-duration DRM experiments under GHSV of 80,000 mL·g cat −1 ·h −1 . This research may provide a simple and effective methodology for the synthesis of stable and efficient DRM catalysts.
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