scholarly journals Substitution of Co with Ni in Co/Al2O3 Catalysts for Fischer–Tropsch Synthesis

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 334
Author(s):  
Michela Martinelli ◽  
Sai Charan Karuturi ◽  
Richard Garcia ◽  
Caleb D. Watson ◽  
Wilson D. Shafer ◽  
...  

The effect of cobalt substitution with nickel was investigated for the Fischer–Tropsch synthesis reaction. Catalysts having different Ni/Co ratios were prepared by aqueous incipient wetness co-impregnation, characterized, and tested using a continuously stirred tank reactor (CSTR) for more than 200 h. The addition of nickel did not significantly modify the morphological properties measured. XRD, STEM, and TPR-XANES results showed intimate contact between nickel and cobalt, strongly suggesting the formation of a Co-Ni solid oxide solution in each case. Moreover, TPR-XANES indicated that nickel addition improves the cobalt reducibility. This may be due to H2 dissociation and spillover, but is more likely the results of a chemical effect of intimate contact between Co and Ni resulting in Co-Ni alloying after activation. FTS testing revealed a lower initial activity when nickel was added. However, CO conversion continuously increased with time on-stream until a steady-state value (34%–37% depending on Ni/Co ratio) was achieved, which was very close to the value observed for undoped Co/Al2O3. This trend suggests nickel can stabilize cobalt nanoparticles even at a lower weight percentage of Co. Currently, the cobalt price is 2.13 times the price of nickel. Thus, comparing the activity/price, the catalyst with a Ni/Co ratio of 25/75 has better performance than the unpromoted catalyst. Finally, nickel-promoted catalysts exhibited slightly higher initial selectivity for light hydrocarbons, but this difference typically diminished with time on-stream; once leveling off in conversion was achieved, the C5+ selectivities were similar (≈ 80%) for Ni/Co ratios up to 10/90, and only slightly lower (≈ 77%) at Ni/Co of 25/75.

2003 ◽  
Vol 36 (7) ◽  
pp. 874-880 ◽  
Author(s):  
Yi Zhang ◽  
Yoshiharu Yoneyama ◽  
Kaoru Fujimoto ◽  
Noritatsu Tsubaki

RSC Advances ◽  
2017 ◽  
Vol 7 (13) ◽  
pp. 7793-7800 ◽  
Author(s):  
Venkat Ramana Rao Pendyala ◽  
Wilson D. Shafer ◽  
Gary Jacobs ◽  
Michela Martinelli ◽  
Dennis E. Sparks ◽  
...  

The effects of co-fed ammonia in synthesis gas on the activity and product selectivities of a typical cobalt catalyst (0.5% Pt–25% Co/Al2O3) were investigated during the Fischer–Tropsch synthesis using a continuously stirred tank reactor (CSTR).


RSC Advances ◽  
2019 ◽  
Vol 9 (25) ◽  
pp. 14176-14187 ◽  
Author(s):  
Sunkyu Yang ◽  
Sungwoo Lee ◽  
Seok Chang Kang ◽  
Seung Ju Han ◽  
Ki-Won Jun ◽  
...  

Intimate contact between Fe5C2 and Na2O leads to high linear olefin selectivity with minimizing branched paraffin formation.


2010 ◽  
Vol 31 (8) ◽  
pp. 919-927 ◽  
Author(s):  
Yuhan SUN ◽  
Jiangang CHEN ◽  
Jungang WANG ◽  
Litao JIA ◽  
Bo HOU ◽  
...  

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