Influence of alloying on the catalytic performance of Ni–Al catalyst prepared from hydrotalcite-like compounds for methane decomposition. (19th January 2021)

• Record Type: Journal Article
• Authors: Wan, Chunsheng; Shi, Zemin; Huang, Min; Pan, Jinhua; Luo, Ruizhi; Li, Dalin; Jiang, Lilong
• Is Part Of: International journal of hydrogen energy. Volume 46:Number 5(2021)
• Page Start: 3833
• Page End: 3846
• Publication Date: 2021-01-19
• Subjects: Catalytic methane decomposition -- Hydrotalcite-like compounds -- Nickel-copper alloy -- Nickel-iron alloy -- Nickel-cobalt alloy; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2020.10.186
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Cobalt-, iron-, and copper-substituted nickel-aluminum hydrotalcite-like compounds (Ni2.7 Co0.3 Al, Ni2.7 Fe0.3 Al, Ni2.7 Cu0.3 Al HTlcs) have been synthesized and used as precursors to prepare Ni–Co, Ni–Fe, and Ni–Cu alloy catalysts for methane decomposition. The catalysts before and after reaction were characterized with various techniques including XRD, H2 -TPR, HAADF-STEM-EDX, SEM, TEM, and Raman. The characterization results indicate that upon calcination HTlcs are transformed into a mixed oxide solid solution, where cobalt, copper, and iron ions are incorporated into the nickel oxide, and the reduction treatment leads to composition-uniform alloy particles. In methane decomposition at 600 °C, alloying Ni with Co, Fe, and especially Cu is found to enhance the catalytic life and carbon yield. The order of activity is Ni2.7 Cu0.3 Al >> Ni2.7 Fe0.3 Al > Ni2.7 Co0.3 Al > Ni3 Al in terms of carbon yield, highlighting that Ni–Cu alloying is the most effective. Besides, Ni–Cu alloying remarkably changes the carbon morphology, giving carbon nanofibers as the main product. TEM and STEM measurements suggest that Ni–Cu alloy particles are readily aggregated into big particles (>60 nm) under the reaction conditions, which may be responsible for the significant effect of Ni–Cu alloying. Highlights: Ni–Co, Ni–Fe, and Ni–Cu alloy particles are composition-uniform. Alloying Ni with Co, Fe, and Cu enhances the catalytic life and carbon yield. The order of activity is Ni–Cu >> Ni–Fe > Ni–Co > Ni in terms of carbon yield. Ni–Cu alloying changes the carbon morphology giving CNFs as the main product. Ni–Cu alloy particles are aggregated into big particles (>60 nm) during the reaction.