Structural transformation of carbon-encapsulated core-shell CoNi nanoparticles during magnetically induced CO 2 reduction into CO

• Published in: Applied catalysis. B, Environmental Environmental, 2024-06, Vol.347
• Main Authors: Cerezo-Navarrete, Christian, Marin, Irene Mustieles, Marini, Carlo, Chaudret, Bruno, Martínez-Prieto, Luis
• Format: Article
• Language: English
• Subjects: Catalysis; Chemical Sciences
• ISSN: 0926-3373
• DOI: 10.1016/j.apcatb.2024.123780

Controlling product distribution in CO2 hydrogenation is of great scientific interest, the selective CO production through the reverse water-gas shift reaction (RWGS) being one of the most investigated processes. Herein, we report the synthesis of new core-shell Co@Ni NPs encapsulated in carbon (Co@Ni@C) to prevent their aggregation at the high-temperatures reached during magnetically induced catalysis. This bifunctional system has been simultaneously used as heating agent and catalyst for the magnetically induced hydrogenation of CO2 . While at low magnetic fields Co@Ni@C produces CH4:CO mixtures, at higher field amplitudes it selectively generates carbon monoxide. Indeed, Co@Ni@C has shown to be one of the most active catalysts reported to date, which reaches a maximum conversion of 74.2 % with complete selectivity towards CO at 53 mT and XXX kHz. In addition, recycling and cyclability experiments have demonstrated that Co@Ni@C becomes fully selective for CO after being exposed to high field amplitudes (i.e. reaction temperature above 400 °C), even when it exposed to low magnetic fields again. This change in the selectivity is due to an atomic rearrangement of the core-shell structure, as was confirmed by EDX, XAS, TPR and TPD analysis.