Preparation and evaluation of mesoporous nickel and manganese bimetallic nanocatalysts in methane dry reforming process for syngas production

Abstract

In this paper, Ni-Mn catalysts supported on mesoporous nanocrystalline γ-Al 2 O 3 were prepared and employed in carbon dioxide reforming of methane for the production of synthesis gas. The physicochemical properties of the catalysts were determined by XRD, BET, TPO and SEM techniques. The obtained results revealed that the Mn-promoted catalysts exhibited higher activity and stability and lower degree of carbon formation compared to unpromoted nickel catalyst. The catalytic results showed that the 10 (wt%) Ni-3 (wt%) Mn/Al 2 O 3 catalyst possessed the highest catalytic activity. The XRD results confirmed that the addition of Mn improves the dispersion of the active metal species on the catalyst or incorporates into the support due to a decrease in the crystallite size of Ni and consequently causes an increase in Ni dispersion. The 10 (wt%) Ni-3 (wt%) Mn/Al 2 O 3 catalyst was stable during 20 hour on stream without any decrease in methane conversion.

Enhanced Long-term Stability and Carbon Resistance of Ni/MnxOy-Al2O3 Catalyst in Near-equilibrium CO2 Reforming of Methane for Syngas Production

“…Using CO2-TPD measurements, the authors showed that higher Mn content (10%) prompted better CO2 adsorption. In addition to the superior promotion of both CO2 and CH4 on the surface of our synthesized materials, we envisage that the presence of an in-situ elimination of carbon via Mn3O4/C/MnO/CO2 redox looping cycle could play a synergetic role which can lead to lowering the amount of surface carbon during the reaction of CO2 reforming of methane [40][41][42]. Where carbon residues are formed on the surface of reduced Ni particles, migration of carbon to neighboring Mn3O4 sites could be anticipated to enable the in-situ elimination of carbon.…”

Effects of alloying for steam or dry reforming of methane: a review of recent studies

“…159 The high hydrogen dissociation capacity of the noble metals might be a factor in the high activity of the catalysts. The addition of a second metal was also found to improve the Ni dispersion in several alloys (Mn-Ni, 97,98 Co-Ni, 116 Rh-Ni, 76 Ir-Ni, 83 Pt-Ni, 84 etc.). As discussed in chapter 3, the Ni particle size has a significant effect on the ease of carbon deposition.…”

“…Mn-Ni. Recently, Najfach et al, 97 and Ramezani et al 98 reported effects of Mn to Ni catalysts. They described effects of increased Ni dispersibility, which led to less coke formation.…”

“…They described effects of increased Ni dispersibility, which led to less coke formation. Ramezani et al 98 described that the Mn could increase the activity because of the higher dispersion of Ni and concluded that 10 wt%Ni-3wt%Mn/Al 2 O 3 is the optimal catalyst, showing long-term stability for 20 h. Najfach et al 97 investigated Mn-Ni catalysts on various zeolite supports. They reported that NH 4 -ZSM5 and NH 4 -Y zeolites have benefits of Mn-Ni such as decreasing the coke formation, decreasing the Ni particle size, and increasing the Ni dispersibility, although the addition of Mn generally engenders decreasing activity.…”

Avaliação da aplicação da argila bentonita como catalisador no processo de pré-tratamento do sabugo de milho.

“….São inúmeras as finalidades industriais das bentonitas e movimentam centenas de milhares de dólares no mercado global a cada ano. Sua aplicação em diversos processos é justificada pelas suas propriedades, que são: elevada área superficial, capacidade adsorvente, propriedades reológicas, pureza química e toxicidade baixa ou inexistente (SILVA FAVERO, 2019).Com características específicas, como boa seletividade, estabilidade química, menor custo e grande disponibilidade, as bentonitas têm sido amplamente utilizadas em aplicações industriais como suportes e catalisadores(LI, 2012;RAMEZANI;MESHKANI;.…”