Fundamentals and catalytic applications of CeO₂-based materials

M. Verónica Ganduglia-Pirovano*^a, Pablo G. Lustemberg ^b, Gustavo E. Murgida^c, Zhong-Kang Han^d,e, Dawei Zhang^d, Yi Gao^d, Valeria Ferrari^c, Ana Maria Llois^c

^aInstituto de Catálisis y Petroleoquímica-CSIC. Madrid, Spain

^bInstituto de Física de Rosario-CONICET-UNR. Rosario, Santa Fe, Argentina

^cCentro Atómico Constituyentes-CNEA and CONICET. San Martín, Buenos Aires, Argentina.

^dShanghai Institute of Applied Physics-CAS. Shanghai, China

^eFritz Haber Institute-MPG. Berlin, Germany.

*vgp@icp.csic.es

Ceria (CeO₂) is the most significant of the oxides of rare-earth metals in industrial catalysis. Deep understanding of the oxygen defect structure of ceria surfaces under reducing conditions is essential to tailor their functionality in catalytic applications. For the CeO₂(111) surface, whether oxygen vacancies prefer the subsurface or the surface, and if surface oxygen vacancies attract or repel, as well as whether oxygen vacancy migration and polaron (Ce³⁺) hopping are entangled, are still heavily debated. Also, a number of ordered phases have been observed upon reductionbut their structures have remained elusive. Here, supported by experimental and theoretical results, the current understanding of the structure of the CeO_2-x (111) surface will be discussed [1-8]. Furthermore, the function of ceria as support in the catalytic activity of metal-ceria systems is not fully understood. Its non-innocent role will be here discussed using ceria-supported metal nanoparticles as model catalysts. Co- and Ni-ceria systems will be used as examples of catalysts for methane dry reforming with CO₂ to produce syngas, a relevant process from the environmental standpoint [9-11]. Ni-ceria will also be considered for the production of two energy vectors, namely, hydrogen [12, 13] and methanol [14], via the water-gas shift reaction and the direct oxidation of methane in the presence of water, respectively.

The collaboration with the experimental groups led by Michael Reichling (Uni. Osnabrück), and Jose A. Rodriguez and Sanja Senanayake (BNL) is deeply acknowledged.

[1] Ganduglia-Pirovano, M. V.; Da Silva, J. L. F.; Sauer, J. Phys. Rev. Lett. 2009, 102, 026101. DOI: 10.1103/PhysRevLett.102.026101

[2] Jerratsch, J. F. et al.Phys. Rev. Lett. 2011, 106, 246801. DOI: 10.1103/PhysRevLett.106.246801

[3] Murgida G. E.; Ganduglia-Pirovano, M. V. Phys. Rev. Lett. 2013, 110, 246101.

DOI: 10.1103/PhysRevLett.110.246101

[4] Murgida, G. E.; Ferrari, V.; Llois, A. M.; Ganduglia-Pirovano, M. V. Phys. Rev. B 2014, 90, 115120. DOI: 10.1103/PhysRevB.90.115120

[5] Olbrich, R. et al.J. Phys. Chem. C 2017, 121, 6844. DOI: 10.1021/acs.jpcc.7b00956

[6] Murgida, G. E.; Ferrari, V.; Llois, A. M.; Ganduglia-Pirovano, M. V. Phys. Rev. Materials 2018, 2, 083609. DOI: 10.1103/PhysRevMaterials.2.083609

[7] Han, Z.-K. et al.Phys. Rev. Materials 2018, 2, 035802. DOI: 10.1103/PhysRevMaterials.2.035802

[8] Zhang, D. et al.Phys. Rev. Lett. 2019, 122, 096101. DOI: 10.1103/PhysRevLett.122.096101

[9] Liu, Z. et al. Angew. Chem., Int. Ed. 2016, 55, 7455. DOI: 10.1002/anie.201602489

[10] Lustemberg, P. G. et al. ACS Catal. 2016, 6, 8184. DOI: 10.1021/acscatal.6b02360

[11] Liu, Z. et al. Angew. Chem. Int. Ed. 2017, 56, 13041. DOI: 10.1002/anie.201707538

[12] Carrasco, J. et al.Angew. Chem. Int. Ed. 2015, 54, 3917. DOI: 10.1002/anie.201410697

[13] Lustemberg, P. G.; Feria, L.; Ganduglia-Pirovano, M. V. J. Phys. Chem. C 2017, 121, 6844. DOI: 10.1021/acs.jpcc.8b06231

[14] Lustemberg, P. G. et al. J. Am. Chem. Soc.2018, 140, 7681. DOI: 10.1021/jacs.8b03809