The Role of Strontium in CeNiO3 Nano-Crystalline Perovskites for Greenhouse Gas Mitigation to Produce Syngas

Abstract

The transition metal-based catalysts for the elimination of greenhouse gases via methane reforming using carbon dioxide are directly or indirectly associated with their distinguishing characteristics such as well-dispersed metal nanoparticles, a higher number of reducible species, suitable metal–support interaction, and high specific surface area. This work presents the insight into catalytic performance as well as catalyst stability of CexSr1−xNiO3 (x = 0.6–1) nanocrystalline perovskites for the production of hydrogen via methane reforming using carbon dioxide. Strontium incorporation enhances specific surface area, the number of reducible species, and nickel dispersion. The catalytic performance results show that CeNiO3 demonstrated higher initial CH4 (54.3%) and CO2 (64.8%) conversions, which dropped down to 13.1 and 19.2% (CH4 conversions) and 26.3 and 32.5% (CO2 conversions) for Ce0.8Sr0.2NiO3 and Ce0.6Sr0.4NiO3, respectively. This drop in catalytic conversions post strontium addition is concomitant with strontium carbonate covering nickel active sites. Moreover, from the durability results, it is obvious that CeNiO3 exhibited deactivation, whereas no deactivation was observed for Ce0.8Sr0.2NiO3 and Ce0.6Sr0.4NiO3. Carbon deposition during the reaction is mainly responsible for catalyst deactivation, and this is further established by characterizing spent catalysts.

CO2‐Steam Bi‐Reforming of Methane Over La1−xSrxNi0.8Zr0.2O3 Perovskite Catalysts to Generate Hydrogen Rich Syngas

“…However, the NiO peak intensity increased with increase in Sr percentage. Also, there was a slight variation in peak position with the addition of Sr as the peak gradually shifted towards higher values and this may be attributed to lattice modification [11,16] . Furthermore, a new La 2 NiO 4 (spinel) phase was formed for Sr rich catalysts due to distortion of perovskite structure after partial substitution of La by Sr [32] .…”

“…The surface area of perovskite catalysts is usually low (<10 m 2 /g) due to high calcination temperature, leading to sintering and formation of large particle size resulting in a lower surface area [11,30] . The surface area of the catalysts increased with an increase in Sr content in La 1−x Sr x Ni 0.8 Zr 0.2 O 3 except for the catalysts for LSNZ6 (with Sr content=0.6) and this may be attributed to the increase in Sr percentage [11] . The improper trend of surface area with Sr content may be due to distortion caused by substituting La with Sr [11] .…”

Resolving a structural issue in cerium-nickel-based oxide: a single compound or a two-phase system?

“…Most of the recently published articles claim that they obtained phase pure CeNiO 3 compound which crystallizes as a perovskite-type oxide. [20][21][22][23][24][25][26][27] Nonetheless, the studies suffer from a lack of thorough physicochemical characterization, typically only showing powder X-ray analysis without providing any crystallographic information. Some authors tried to index the X-ray diffraction (XRD) pattern to the orthorhombic crystal system, space group Pnma with no detailed structural characterization.…”

Green Fabrication of Heterostructured CoTiO3/TiO2 Nanocatalysts for Efficient Photocatalytic Degradation of Cinnamic Acid

“…This method uses citric acid as a complexing agent and metallic nitrates as precursors. Several other synthesis methods are also used for the preparation of perovskites, such as the Pechini method, sol–gel self-combustion method that uses citric acid monohydrate (C 6 H 8 O 7 ·H 2 O) as the complexing agent, and lanthanum oxide (La 2 O 3 ), cobalt nitrate hexahydrate (Co­(NO 3 ) 2 ·6H 2 O), nickel nitrate hexahydrate (Ni­(NO 3 ) 2 ·6H 2 O), and ferric nitrate nonahydrate (Fe­(NO 3 ) 3 ·9H 2 O) as precursors, and the self-combustion method that uses metallic nitrates and glycine as a precursor for the preparation of nanocrystalline perovskites, Ce x Sr 1– x NiO 3 ( x = 0.6–1.0), nanocrystals SrNiO 3 and CeNiO 3 , and La 1– x Sr x NiO 3 perovskite-type oxides. , Of the methods used to prepare perovskite-like materials, hydrothermal synthesis in supercritical water has advantages because the reaction rate is enhanced more than 10 3 times that under the conventional hydrothermal conditions with the products of high crystallinity and at relatively low temperatures, below 300 °C, since ionic products (Kw) have a maximum value of around 250–300 °C . Hydrothermal methods for preparing fine metal oxide particles in subcritical and supercritical water have been developed using batch reaction − and flow reaction systems. − …”

“… 33 This method uses citric acid as a complexing agent and metallic nitrates as precursors. Several other synthesis methods are also used for the preparation of perovskites, such as the Pechini method, 34 sol–gel self-combustion method that uses citric acid monohydrate (C 6 H 8 O 7 ·H 2 O) as the complexing agent, and lanthanum oxide (La 2 O 3 ), cobalt nitrate hexahydrate (Co(NO 3 ) 2 ·6H 2 O), nickel nitrate hexahydrate (Ni(NO 3 ) 2 ·6H 2 O), and ferric nitrate nonahydrate (Fe(NO 3 ) 3 ·9H 2 O) as precursors, 35 and the self-combustion method that uses metallic nitrates and glycine as a precursor for the preparation of nanocrystalline perovskites, Ce x Sr 1– x NiO 3 ( x = 0.6–1.0), 36 nanocrystals SrNiO 3 and CeNiO 3 , 37 37 and La 1– x Sr x NiO 3 perovskite-type oxides. 38 , 39 Of the methods used to prepare perovskite-like materials, hydrothermal synthesis in supercritical water has advantages because the reaction rate is enhanced more than 10 3 times that under the conventional hydrothermal conditions with the products of high crystallinity and at relatively low temperatures, below 300 °C, since ionic products (Kw) have a maximum value of around 250–300 °C.…”