scholarly journals One-Step Synthesis of Highly Dispersed and Stable Ni Nanoparticles Confined by CeO2 on SiO2 for Dry Reforming of Methane

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5956
Author(s):  
Chengyang Zhang ◽  
Renkun Zhang ◽  
Hui Liu ◽  
Qinhong Wei ◽  
Dandan Gong ◽  
...  

Sintering and carbon deposition are the two main ways to deactivate Ni-based catalysts during methane reforming. Herein, a stable Ni-CeO2/SiO2(CSC) catalyst was prepared by a one-step colloidal solution combustion method (CSC) and used for dry reforming of methane. In the catalyst, the small Ni particles were confined by CeO2 particles and highly dispersed on the surface of SiO2, forming a spatial confinement structure with a rich Ni-CeO2 interface in the catalyst. The Ni-CeO2/SiO2(CSC) catalyst prepared by the one-step CSC method exhibited superior activity at 700 °C during dry reforming of methane, and the performance of the catalyst was stable after 20 h of reaction with only a small amount of carbon deposition present (1.8%). Due to the spatial confinement effect, Ni was stable and less than 5 nm during reaction. The small Ni particle size and rich Ni-CeO2 interface reduced the rate of carbon deposition. This colloidal combustion method could be applied to prepare stable metal-based catalysts with rich metal–oxide interfaces for high-temperature reactions.

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 38 ◽  
Author(s):  
Luhui Wang ◽  
Rong Hu ◽  
Hui Liu ◽  
Qinhong Wei ◽  
Dandan Gong ◽  
...  

Ni nanoparticles encapsulated within La2O3 porous system (Ni@La2O3), the latter supported on SiO2 (Ni@La2O3)/SiO2), effectively inhibit carbon deposition for the dry reforming of methane. In this study, Ni@La2O3/SiO2 catalyst was prepared using a one-pot colloidal solution combustion method. Catalyst characterization demonstrates that the amorphous La2O3 layer was coated on SiO2, and small Ni nanoparticles were encapsulated within the layer of amorphous La2O3. During 50 h of dry reforming of methane at 700 °C and using a weight hourly space velocity (WHSV) of 120,000 mL gcat−1 h−1, the CH4 conversion obtained was maintained at 80%, which is near the equilibrium value, while that of impregnated Ni–La2O3/SiO2 catalyst decreased from 63% to 49%. The Ni@La2O3/SiO2 catalyst exhibited very good resistance to carbon deposition, and only 1.6 wt% carbon was formed on the Ni@La2O3/SiO2 catalyst after 50 h of reaction, far lower than that of 11.5 wt% deposited on the Ni–La2O3/SiO2 catalyst. This was mainly attributed to the encapsulated Ni nanoparticles in the amorphous La2O3 layer. In addition, after reaction at 700 °C for 80 h with a high WHSV of 600,000 mL gcat−1 h−1, the Ni@La2O3/SiO2 catalyst exhibited high CH4 conversion rate, ca. 10.10 mmol gNi−1 s−1. These findings outline a simple synthesis method to prepare supported encapsulated Ni within a metal oxide porous structure catalyst for the dry reforming of methane reaction.


Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1055 ◽  
Author(s):  
Ye Wang ◽  
Li Li ◽  
Yannan Wang ◽  
Patrick Da Costa ◽  
Changwei Hu

Yttrium-doped NiO–ZrOm catalyst was found to be novel for carbon resistance in the CO2 reforming of methane. Yttrium-free and -doped NiO–ZrOm catalysts were prepared by a one-step urea hydrolysis method and characterized by Brunauer-Emmett-Teller (BET), TPR-H2, CO2-TPD, XRD, TEM and XPS. Yttrium-doped NiO–ZrOm catalyst resulted in higher interaction between Ni and ZrOm, higher distribution of weak and medium basic sites, and smaller Ni crystallite size, as compared to the Y-free NiO–ZrOm catalyst after reaction. The DRM catalytic tests were conducted at 700 °C for 8 h, leading to a significant decrease of activity and selectivity for the yttrium-doped NiO–ZrOm catalyst. The carbon deposition after the DRM reaction on yttrium-doped NiO–ZrOm catalyst was lower than on yttrium-free NiO–ZrOm catalyst, which indicated that yttrium could promote the inhibition of carbon deposition during the DRM process.


Author(s):  
Xinyu Chen ◽  
Wei Ding ◽  
Zhiwei Yao ◽  
Na Sun ◽  
Zhimeng Wang ◽  
...  

A Highly dispersed NiMoP phosphide catalyst with an average particle size of 9.1 nm and a carbon content of 53.5 wt% was firstly synthesized by carbothermal route using glucose as...


Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 750 ◽  
Author(s):  
Ali M. A. Al-Najar ◽  
Faris A. J. Al-Doghachi ◽  
Ali A. A. Al-Riyahee ◽  
Yun Hin Taufiq-Yap

Pt,Pd,Ni/MgO, Pt,Pd,Ni/Mg0.97La3+0.03O, Pt,Pd,Ni/Mg0.93La3+0.07O, and Pt,Pd,Ni/Mg0.85La3+0.15O (1% of each of the Ni, Pd, and Pt) catalysts were prepared by a surfactant-assisted co-precipitation method. Samples were characterized by the XRD, XPS, XRF, FT-IR, H2-TPR, TEM, the Brunauer–Emmett–Teller (BET) method, and TGA and were tested for the dry reforming of methane (DRM). TEM and thermal gravimetric analysis (TGA) methods were used to analyze the carbon deposition on spent catalysts after 200 h at 900 °C. At a temperature of 900 °C and a 1:1 CH4:CO2 ratio, the tri-metallic Pt,Pd,Ni/Mg0.85La3+0.15O catalyst with a lanthanum promoter showed a higher conversion of CH4 (85.01%) and CO2 (98.97%) compared to the Ni,Pd,Pt/MgO catalysts in the whole temperature range. The selectivity of H2/CO decreased in the following order: Pt,Pd,Ni/Mg0.85La3+0.15O > Pt,Pd,Ni/Mg0.93La3+0.07O > Pt,Pd,Ni/Mg0.97La3+0.03O > Ni,Pd,Pt/MgO. The results indicated that among the catalysts, the Pt,Pd,Ni/Mg0.85La23+0.15O catalyst exhibited the highest activity, making it the most suitable for the dry reforming of methane reaction.


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