Mn Modified Ni/Bentonite for CO2 Methanation

Abstract

To enhance the low-temperature catalytic activity and stability of Ni/bentonite catalyst, Ni-Mn/bentonite catalyst was prepared by introducing Mn into Ni/bentonite catalyst and was used for CO 2 methanation. The results indicated that the addition of Mn enhanced the interaction between the NiO and the bentonite carrier, increased the dispersion of the active component Ni and decreased the grain size of the active component Ni, increased the specific surface area and pore volume of the Ni/bentonite catalyst, and decreased the average pore size, which suppressed the aggregation of Ni particles grown during the CO 2 methanation process. At the same time, the Mn addition increased the amount of oxygen vacancies on the Ni/bentonite catalyst surface, which promoted the activation of CO 2 in the methanation reaction, increasing the low-temperature activity and stability of the Ni/bentonite catalyst. Under the reaction condition of atmospheric pressure, 270 • C, V(H 2 ):V(CO 2 ) = 4, and feed gas space velocity of 3600 mL·g cat −1 ·h −1 , the CO 2 conversion on the Ni-Mn/bentonite catalyst with 2wt% Mn was 85.2%, and the selectivity of CH 4 was 99.8%. On the other hand, when Mn was not added, the CO 2 conversion reached 84.7% and the reaction temperature only raised to 300 • C. During a 150-h stability test, the CO 2 conversion of Ni-2wt%Mn/bentonite catalyst decreased by 2.2%, while the CO 2 conversion of the Ni/bentonite catalyst decreased by 6.4%.

Hydrogenation of Furfural to Furfuryl Alcohol over Nickel Supported Bentonite Catalyst

“…In the pressure region P/P 0 >0.4, an H3‐type hysteresis loop was generated by capillary condensation in the pores. The above results indicate that the incorporation of nickel on bentonite support causes a decrease in the specific surface area due to partial blockage of mesopores by Ni particles [26,27] …”

“…The above results indicate that the incorporation of nickel on bentonite support causes a decrease in the specific surface area due to partial blockage of mesopores by Ni particles. [26,27] The study of the oxidation state of elements of Ni/ Bentonite-20-C was done by X-ray photoelectron spectroscopy (XPS) (Figure 4). The survey scan (Figure 4a) exhibited the presence of the respective metals.…”

The Effect of Si on CO2 Methanation over Ni-xSi/ZrO2 Catalysts at Low Temperature

“…The presence of oxygen vacancies was beneficial to the adsorption of CO 2 , which could promote CO 2 activation [23,58]. Jiang et al [17] found that the content of surface oxygen on the Mn promoted Ni/bentonite catalyst was 83.55%, which was higher than that of the unpromoted Ni/bentonite catalyst (74.85%), representing the higher amount of oxygen vacancies. The increased oxygen vacancies were helpful to the adsorption and dissociation of CO 2 on the catalyst.…”

“…Meanwhile, the heat released during the reaction will lead to the sintering of metal particles and deactivation of the catalysts [9,16]. Therefore, designing a high active and stable catalyst operating at low temperature is important [17].…”

Highly Dispersed Ni Nanocatalysts Derived from NiMnAl-Hydrotalcites as High-Performing Catalyst for Low-Temperature Syngas Methanation

“…Until now, all commercial methanation catalysts for SNG production have been Ni-based catalysts due to their high performance and low cost [6][7][8][9][10][11][12][13][14][15][16][17][18]. Nevertheless, the major weaknesses of nickel catalysts include agglomeration of Ni nanoparticles, formation of carbon deposits at higher temperatures, and poor activity at low temperatures (250 • C) for the complete methanation of syngas [19][20][21][22][23][24][25][26][27][28][29][30][31]. The increase in low temperature performance of the Ni catalysts in syngas methanation is critical.…”