Nanocomposites and nanomaterials

Silica based heterometallic Ni, Co and Fe-containing nanocomposites in the reaction of CO2 methanation
Dyachenko А.G.1, Ischenko O.V.1, Goncharuk O.V.2, Borysenko M.V.2, Sulym I.Ya2., Dariusz Sternik3
1Taras Shevchenko National University of Kyiv, 64/13 Volodymyrs’ka Str, Kyiv, 01601, Ukraine; e-mail: dyachenko.alla@yahoo.com
2O.O. Chuiko Institute of Surface Chemistry National Academy of Science of Ukraine, 17 General Naumov Str, Kyiv, 03164, Ukraine
3Maria Curie-Sklodowska University, M.C. Sklodowska Sq.3, 20031 Lublin, Poland.

For effective CO2 methanation, heterometallic Ni, Co and Fe-containing nanocomposite catalysts, have been prepared with solvate-stimulated modification, thermal decomposition, and chemical reduction stages using nanosilica A-300 as a carrier. The catalysts were characterized with nitrogen adsorption, X-ray powder diffraction and TPD MS surface analysis. The prepared Fe-containing catalysts exhibited high activity in the CO2 methanation with 72-76 % of CH4 yield at 450 °C. The formers are characterized by the small crystallites of 20-27 nm in size. The results of TPD MS revealed that the catalytic reaction is passed through the formation of O-containing intermediates. Table 1 presents the texture characteristics of the carrier and nanocomposites in the oxide and metallic station. All studied samples are characterized by an increase in the contribution of mesopores compared to the pristine SiO2. After reduction of metal oxides to the metallic state, the change in the textural characteristics depends on the composition of the active mass applied to the carrier.
Table 1. Textural characteristics of Ni(19)Co(77)Fe(4)/SiO2, Ni(80)Fe(20)/SiO2, and Co(90)Fe(10)/SiO2 oxides and reduced nanocomposites
Sample	SBET,
m2/g	Smicro,
m2/g	Smeso,
m2/g	Smacro,
m2/g	Vmicro,
cm3/g	Vmeso, cm3/g	Vmacro,
cm3/g	Vp,
cm3/g	Rp,V
nm	
SiO2 (A300)	271	24.4	239.6	6.5	0.025	0.501	0.149	0.674	17.4	
NiFeCo/SiO2(o)	222	14.2	202.1	5.8	0.007	0.737	0.114	0.858	18.7	
NiFeCo/SiO2(r)	218	9.4	201.8	7.2	0.005	0.732	0.142	0.879	19.2	
NiFe/SiO2(o)	206	40.2	163.0	2.7	0.019	0.670	0.056	0.745	12.9	
NiFe/SiO2 (r)	187	37.6	146.3	2.8	0.019	0.650	0.056	0.726	12.0	
CoFe/SiO2 (o)	187	44.7	139.5	2.7	0.023	0.709	0.058	0.790	13.5	
CoFe/SiO2 (r)	186	43.6	140.0	2.4	0.022	0.757	0.056	0.835	13.4