Synthesis and Application of Cerium-Incorporated SBA-16 Supported Ni-Based Oxygen Carrier in Cyclic Chemical Looping Steam Methane Reforming

Abstract

Hydrogen, as a clean energy carrier, could be produced aided by cyclic oxidation-reduction of oxygen carriers (OCs) in contact with carbonaceous fuel in chemical looping steam methane reforming (CL-SMR) process. In this study, the cerium was incorporated into the SBA-16 support structure to synthesize the Ni/Ce-SBA-16 OC. The supports were synthesized using hydrothermal method followed by impregnation of Ni and characterized via low and wide angle X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), coupled with energy dispersive X-ray (EDX) spectroscopy, and transmission electron micrograph (TEM) techniques. In addition, the effect of various Si/Ce molar ratios (20-60) in the support structure, Ni loading (10-30 wt %), reaction temperature (500-750 • C), and life time of optimal oxygen carrier over 16 cycles were investigated. The results of wide angle XRD and SEM revealed that the incorporation of CeO 2 in the channels of SBA-16 caused the formation of nickel metallic particles with smaller size and prevents the coke formation. The results showed that OC with 15 wt % Ni and Si/Ce molar ratio of 40 (15Ni/Ce-SBA-16(40)) has the best performance when compared with other OCs in terms of catalytic activity and structural properties. The methane conversion of about 99.7% was achieved at 700 • C using 15Ni/Ce-SBA-16(40) OC. We anticipate that the strategy can be extended to investigate a variety of novel modified mesoporous silica as the supporting material for the Ni based OCs.

Relationship Between the Pore Structure of Mesoporous Silica Supports and the Activity of Nickel Nanocatalysts in the CO2 Reforming of Methane

“…The discovery of Mobil Crystalline Materials, such as MCM-41 in 1992 by Mobil Oil Corporation scientists [1], has initiated intensive attention in the development of mesoporous silica materials and their applications in research and industry [2][3][4][5][6][7][8][9][10][11][12][13][14]. Afterwards, a range of highly ordered mesoporous silica materials such as SBA-15 and KIT-6 have been created in 1998 and 2003, respectively [15,16].…”

“…A range of approaches has been developed to overcome this obstacle. Optimising the pore size and the development of hierarchical porous materials including different pore size systems have received special attention in recent years [9][10][11][12][13][14]37,38,[40][41][42][43][44][45][46][47][48][49][50][51][52][53]. This is because the hierarchical porous structure of the silica supports can not only increase the mass transport of the reactants to the Ni active sites, but also the mesoporous matrix hinders the thermal sintering of the Ni particles by the confinement effect [24,[54][55][56].…”

Chemical looping reforming: process fundamentals and oxygen carriers

“…The SBA-16 is also applied to Ni-based oxygen carriers [131]. In order to improve the performance of chemical looping steam methane reforming, Rahimpour et al [131,[219][220][221] carried out a series of studies on the application of Ni/SBA-16 oxygen carriers in chemical looping steam methane reforming, and conducted in-depth discussions on the properties of Ni/SBA-16 oxygen carriers and their modification by Ce and Y. With SBA as the support and the addition of Ce as the promoter, the performance of chemical looping steam methane reforming was significantly improved.…”

Chemical Looping Combustion over Yolk–Shell-Type Alumina-Based Oxygen Carrier: Catalytic Structure and Process Activity

“…The rise in atmospheric carbon dioxide levels is a significant concern, as it is one of the primary drivers of climate change. − This increment is mainly due to human actions, including deforestation, the combustion of fossil fuels, and other industrial and agricultural practices. − As the concentration of CO 2 increases, it traps more heat in the atmosphere, leading to rising global temperatures and a range of associated effects such as more intense and frequent extreme weather events, rising sea levels, and alterations in patterns of precipitation. , …”