Improving the performance of nickel catalyst supported on mesostructured silica nanoparticles in methanation of CO 2 -ri
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ORIGINAL PAPER
Improving the performance of nickel catalyst supported on mesostructured silica nanoparticles in methanation of CO2‑rich gas by urea–nitrate combustion Phung‑Anh Nguyen1 · Cam‑Loc Luu1,2 · Thi‑Thuy‑Van Nguyen1,2 · Tri Nguyen1 · Tien‑Cuong Hoang1 Received: 1 October 2019 / Accepted: 16 May 2020 © Institute of Chemistry, Slovak Academy of Sciences 2020
Abstract In this work, NiO supported mesostructured silica nanoparticles (MSN) were synthesized via the urea–nitrate combustion method using urea as fuel and nitrate salts as oxidants with the different urea/nitrate ratios and calcination duration. The physicochemical properties of catalysts were investigated by several techniques, including N2 physisorption measurements, powder X-ray diffraction, N2-BET isothermal adsorption, hydrogen temperature-programmed reduction, carbon dioxide temperature-programmed desorption, scanning electron microscopy and transmission electron microscopy. The obtained catalysts were employed in the methanation of C O2-rich gas at a temperature range of 225–400 °C with the C O2/H2 ratio of 1/4 and C O2 concentration of 20 mol%. The results showed that using the urea–nitrate combustion method in synthesizing catalysts led to improved physicochemical properties that increased the activity of NiO/MSN catalysts. The catalyst prepared with the urea/nitrate molar ratio of 3 and calcined at 600 °C for 3 h showed the highest catalytic performance in methanation of CO2-rich gas, reaching CO2 conversion of 96% and CH4 selectivity of 100% at 375 °C. The best catalyst has excellent stability in CO2 solo-hydrogenation at a reaction temperature of 375 °C during 30 h of reaction thanks to the resistance to coke formation. Besides, adding 1 mol% CO in the feedstock should be simultaneously conducted to surge the effectivity of CO2 methanation. Keywords Nickel catalyst · MSN · CO2-rich gas · Urea–nitrate combustion · CO promotion
Introduction Synthetic gas fuel, especially CH4, synthesized via hydrogenation of carbon oxides is considered as a renewable fuel because it originates from carbon oxides and stabilizes the CO2 concentration in the atmosphere. Nowadays, the development of catalysts with highly active, selective and stable properties as well as resistance for sintering, coking and poisoning in methanation of CO2-rich gas is being still a challenge. Catalysts based on nickel remain the most widely studied for both CO and C O2 methanation. High dispersion of NiO species has often been achieved by the application of * Cam‑Loc Luu [email protected] 1
Institute of Chemical Technology-VAST, 01 Mac Dinh Chi Str., Ho Chi Minh City, Vietnam
Graduate University of Science and Technology – VAST, 18 Hoang Quoc Viet Str., Hanoi, Vietnam
2
the supports of high specific surface area, such as γ-Al2O3, SiO2 and TiO2. However, they have certain disadvantages such as low activity, low selectivity and easiness to form coke (Frontera et al. 2017). This is due to the relatively large Ni particle size, which is not small
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