NAP-XPS study of CO2 reduction over Ni loaded ceria-based nanostructured catalysts

ERIC PELLEGRIN; CARLOS ESCUDERO; JUAN PINTADO; GINESA BLANCO; FACUNDO CARLOS HERRERA

Dresden

Conferencia; ECASIA 2019. 18th European Conference on Applications of Surface and Interface Analysis.; 2019

Despite the increasing economic incentives and environmental advantages associated to theirsubstitution, carbon-rich fossil fuels are expected to remain as the dominant worldwide source of energythrough at least the next two decades and perhaps later. Such an extensive use of these fuels, togetherwith the still low efficiency of most energetic processes, has led to a steady raise of the atmospheric levelsof CO2, and consequently to an aggravation of the global warming observed over the last decades.Therefore, both the control and reduction of CO2 emissions have become an environmental issue of majorconcern and a big challenge for the international scientific community. Among the proposed strategies toeffectively achieve this goal, conversion of CO2 into a variety of chemicals and fuels of high added value,such as methane, methanol or dimethylether, has been widely agreed as the most attractive one from theenvironmental and economic points of view [1]. This conversion involves the reduction of the highly stableCO2 molecules and thereby the application of catalytic processes.In this work, the catalytic reduction of CO2 with H2 has been tested on Ni-loaded ceria-basednanostructured catalysts. Ceria nanocubes were prepared by hydrothermal synthesis, and covered by athin layer of praseodymia deposited by controlled precipitation [2]. The nanocubes were used as supportfor nickel catalysts, where nickel was deposited following the same controlled precipitation method. BothNi catalysts and supports were studied during CO2 reduction by means of NAP-XPS.The reaction, with CO2:H2 ratio 1:4, was followed at different temperatures, from 250ºC up to 640ºC. Maincore levels were collected at two different mean kinetic energies, to obtain data corresponding to twodifferent depths, about 2 and 4 nm. Differences in ceria oxidation state as well as in O 1s and C 1s corelevels were followed and analysed.Financial support from MINECO/FEDER (project MAT2017-87579-R) and Junta de Andalucía (groups FQM110and FQM334) is gratefully acknowledged. A. Barroso-Bogeat thanks support from the ?Juan de la Cierva-Formación? Fellowship Program of MICINN (FJCI-2015-25999). NAPP-XPS experiments were performed atBL24-CIRCE beamline at ALBA Synchrotron (proposal ID: 2018093041)References[1] Y.Zheng, et al., Chem.Soc.Rev, 46 (2017)1427-1463