RESUMO
The catalytic hydrogenation of CO2 to methane is one of the highly researched areas for the production of chemical fuels. The activity of catalyst is largely affected by support type and metal-support interaction deriving from the special method during catalyst preparation. Hence, we employed a simple solvothermal technique to synthesize Ni-based catalysts with different supports and studied the support role (CeO2, Al2O3, ZrO2, and La2O3) on structure-activity relationships in CO2 methanation. It is found that catalyst morphology can be altered by only changing the support precursors during synthesis, and therefore their catalytic behaviours were significantly affected. The Ni/Al2O3 with a core-shell morphology prepared herein exhibited a higher activity than the catalyst prepared with a common wet impregnation method. To have a comprehensive understanding for structure-activity relationships, advanced characterization (e. g., synchrotron radiation-based XAS and photoionization mass spectrometry) and in-situ diffuse reflectance infrared Fourier transform spectroscopy experiments were conducted. This research opens an avenue to further delve into the role of support on morphologies that can greatly enhance catalytic activity during CO2 methanation.
RESUMO
Potassium ions batteries (PIBs) have been regarded as a promising choice for electrical energy storage technology due to the wide distribution of potassium resources. However, developing low-cost and robust earth-rich anode materials is still a major challenge for the practical and scalable usage of PIBs. Herein, for the first time, we developed nitrogen doped carbon coating CoS2/CuCo2S4 heterostructure (CoS2/CuCo2S4@NCs) hollow spheres and evaluated as anode for PIBs. The CoS2 and CuCo2S4 heterostructure interface could generate a built-in electric field, which can fasten electrons transportation. The nanostructures could shorten the diffusion length of K+ and provide large surface area to contact with electrolytes. Furthermore, the inner hollow sphere morphology along with the carbon layer could accommodate the volume expansion during cycling. What's more, the N-doped carbon could increase the conductivity of the anodes. Benefitting from the above features, the CoS2/CuCo2S4@NCs displays an outstanding rate capability (309 mAh g-1 at 500â¯mAâ¯g-1 after 250 cycles) and a long-term cycling life (112 mAh g-1 at 1000â¯mAâ¯g-1 after 1000 cycles) in ether-based electrolyte. Conversion reaction mechanism in CoS2/CuCo2S4@NCs anode is also revealed through ex situ XRD characterizations. This work provides a practical direction for investigating metal sulfides as anode for PIBs.
