Oxidative coupling of methane over NbO (p-type) and Nb2O5 (n-type) semiconductor materials

1996 ◽  
Vol 38 (3-4) ◽  
pp. 215-218 ◽  
Author(s):  
Yesim Erarslanoglu ◽  
Isik Onal ◽  
Timur Dogu ◽  
Selim Senkan
2011 ◽  
Vol 121-126 ◽  
pp. 1526-1529
Author(s):  
Ke Gao Liu ◽  
Jing Li

Bulk Fe4Sb12 and Fe3CoSb12 were prepared by sintering at 600 °C. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, the major phases of bulk samples are skutterudite with impurity phase FeSb2. The electric resistivities of the samples increase with temperature rising at 100~500 °C. The bulk samples are P-type semiconductor materials. The Seebeck coefficients of the bulk Fe4Sb12 are higher than those of bulk Fe3CoSb12 samples at 100~200 °C but lower at 300~500 °C. The power factor of the bulk Fe4Sb12 samples decreases with temperature rising while that of bulk Fe3CoSb12 samples increases with temperature rising at 100~500 °C. The thermal conductivities of the bulk Fe4Sb12 samples are relatively higher than those of and Fe3CoSb12, which maximum value is up to 0.0974 Wm-1K-1. The ZT value of bulk Fe3CoSb12 increases with temperature rising at 100~500 °C, the maximum value is up to 0.031.The ZT values of the bulk Fe4Sb12 samples are higher than those of bulk Fe3CoSb12 at 100~300 °C while lower at 400~500 °C.


2018 ◽  
Vol 30 (35) ◽  
pp. 1706262 ◽  
Author(s):  
Feng Teng ◽  
Kai Hu ◽  
Weixin Ouyang ◽  
Xiaosheng Fang

2011 ◽  
Vol 71-78 ◽  
pp. 3741-3744
Author(s):  
Ke Gao Liu ◽  
Jing Li

For investigating the thermoelectric properties, bulk FeSb2and the composite of CoSb3:FeSb2=7:3 was prepared via sintering. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, bulk FeSb2and the composite of CoSb3:FeSb2=7:3 are P-type semiconductor materials. The electric resistivity of bulk FeSb2sample increases with temperature rising while that of the composite (CoSb3:FeSb2=7:3) decreases with temperature rising. The Seebeck coefficient of the composite (CoSb3:FeSb2=7:3) is evidently higher than that of bulk FeSb2. The thermal conductivities of the composite (CoSb3:FeSb2=7:3) are relatively lower than those of bulk FeSb2. TheZTvalues of bulk FeSb2sample are lower than those of the composite (CoSb3:FeSb2=7:3), that of the later increases with temperature rising at 100~500°C, the maximum value is up to 0.1647.


2019 ◽  
Vol 9 (6) ◽  
pp. 1349-1356 ◽  
Author(s):  
Johnny Zhu Chen ◽  
Zhenwei Wu ◽  
Xiaoben Zhang ◽  
Slgi Choi ◽  
Yang Xiao ◽  
...  

Identification of a Pt3Bi nanoscale, surface intermetallic alloy catalyst for non-oxidative coupling of methane (NOCM).


2021 ◽  
Author(s):  
P. Saychu ◽  
M. Thanasiriruk ◽  
C. Khajonvittayakul ◽  
R. Viratikul ◽  
V. Tongnan ◽  
...  

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 388
Author(s):  
Yuqiao Fan ◽  
Changxi Miao ◽  
Yinghong Yue ◽  
Weiming Hua ◽  
Zi Gao

In this work, Ho2O3 nanosheets were synthesized by a hydrothermal method. A series of Sr-modified Ho2O3 nanosheets (Sr-Ho2O3-NS) with a Sr/Ho molar ratio between 0.02 and 0.06 were prepared via an impregnation method. These catalysts were characterized by several techniques such as XRD, N2 adsorption, SEM, TEM, XPS, O2-TPD (temperature-programmed desorption), and CO2-TPD, and they were studied with respect to their performances in the oxidative coupling of methane (OCM). In contrast to Ho2O3 nanoparticles, Ho2O3 nanosheets display greater CH4 conversion and C2-C3 selectivity, which could be related to the preferentially exposed (222) facet on the surface of the latter catalyst. The incorporation of small amounts of Sr into Ho2O3 nanosheets leads to a higher ratio of (O− + O2−)/O2− as well as an enhanced amount of chemisorbed oxygen species and moderate basic sites, which in turn improves the OCM performance. The optimal catalytic behavior is achievable on the 0.04Sr-Ho2O3-NS catalyst with a Sr/Ho molar ratio of 0.04, which gives a 24.0% conversion of CH4 with 56.7% selectivity to C2-C3 at 650 °C. The C2-C3 yield is well correlated with the amount of moderate basic sites present on the catalysts.


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