Enhancement of the Generation and Transfer of Active Oxygen in Ni/CeO2 Catalysts for Soot Combustion by Controlling the Ni–Ceria Contact and the Three-Dimensional Structure

The effect of the three-dimensionally ordered macroporous (3DOM) structure and the Ni doping of CeO2 on the physicochemical properties and catalytic activity for soot combustion was studied. Moreover, the way in which Ni is introduced to the ceria support was also investigated. For this, CeO2 supports were synthesized with uncontrolled (Ref) and 3DOM-structured morphology, and their respective Ni/CeO2 catalysts were prepared by impregnation of the previously synthesized supports or by successive impregnation of both precursors (Ni and Ce) on the 3DOM template. Conclusions reached in this study are: (1) the 3DOM structure increases the surface area of the catalysts and improves the catalyst–soot contact. (2) The doping of CeO2 with Ni improves the catalytic activity because the NiO participates in the catalytic oxidation of NO to NO2, and also favors the production of active oxygen and the catalyst oxygen storage capacity. (3) Ni incorporation method affects its physicochemical and catalytic properties. By introducing Ni by successive infiltration in the solid template, the CeO2 crystal size is reduced, Ni dispersion is improved, and the catalyst reducibility is increased. All of these characteristics make the catalyst synthesized by successive infiltration to have higher catalytic activity for soot combustion than the Ni-impregnated CeO2 catalyst.The authors thank the financial support from the Spanish Ministry of Economy and Competitiveness (Project CTQ2015-67597-C2-2-R and Grant FJCI-2015-23769), the Spanish Ministry of Education, Culture and Sports (Grant FPU14/01178), Generalitat Valenciana (Project PROMETEO/2018/076), and the UE (FEDER funding)

Shaping a soot combustion Ce0.5Pr0.5Ox catalyst

A Ce0.5Pr0.5Ox soot combustion catalyst has been shaped combining this material prepared in two different structures (nanoparticles and MS-macroporous) in a single active phase. Nanoparticles, prepared by reversed microemulsion method, provide high activity to the hybrid material, and the MS structure, obtained by a hard template synthesis method, provides high thermal stability and improved soot-catalyst contact. Ce0.5Pr0.5Ox nanoparticles present high surface area (148 m2/g; 5 nm) and improved redox properties with regard to other Ce0.5Pr0.5Ox structures, and the macropores size of MS Ce0.5Pr0.5Ox are large enough (around 100 nm) to properly disperse Ce0.5Pr0.5Ox nanoparticles inside and also to host soot particles, creating a high reactive catalyst environment. As a result, the as prepared Ce0.5Pr0.5Ox hybrid catalyst, mixed in loose-contact mode with soot, decreased soot combustion by ca. 100 °C with regard to the uncatalyzed reaction, and thermal aging at 800 °C only decreased this difference to ca. 75 °C. The as-prepared counterpart hybrid catalyst obtained dispersing pure ceria nanoparticles on pure ceria MS support was also active for soot combustion, but the activity was almost lost completely upon thermal aging due to ceria sintering.The authors thank the financial support of the Spanish Ministry of Economy and Competitiveness (Project CTQ2015-67597-C2-2-R), Generalitat Valenciana (Project PROMETEO/2018/076), Junta de Andalucía (Project P18-RTJ-2974) and the UE (FEDER funding)

PrOx nanoparticles: active and stable catalysts for soot combustion

PrOx nanoparticles (10nm; 81m2/g) were synthesized and analysed as soot combustion catalyst in comparation with other reference materials including CeO2 nanoparticles and PrOx and CeO2 catalysts with three dimensionally ordered (3DOM) and without controlled structure. PrOx nanoparticles reached the highest activity; T50 decreases from 603 °C (uncatalysed combustion) to 494 °C. This high activity can be attributed to the high surface area/low crystal size, which enhances the soot catalyst contact, and to the improved reducibility. PrOx nanoparticles kept high activity (T50 = 520 °C) after aging at 800 °C, being significantly more active than aged PrOx catalysts with 3DOM and uncontrolled structure and also significantly more active than all aged CeO2 catalysis which suffer almost total deactivation upon aging. In all cases, PrOx catalysts are more active than CeO2 counterpart materials with the same structure and thermal history, and this applies to nanoparticles, 3DOM and uncontrolled structures.The authors thank the financial support of the Spanish Ministry of Economy and Competitiveness (Project CTQ2015-67597-C2-2-R), Ministry of Science, Innovation and Universities (Project PID2019-105960RB-C22), Generalitat Valenciana (Project PROMETEO/2018/076 and grant APOSTD/2019/030), Junta de Andalucía (Project P18-RTJ-2974), University of Alicante (Project GRE18-01A) and the UE (FEDER funding)

Detección y estimulación temprana de la vocación científica en Química

El objetivo general de esta intervención educativa es dar al alumnado la oportunidad de tener una experiencia anticipada en tareas de investigación previa a la realización del TFG en química. Con esto se pretende que el alumnado disponga de un mejor criterio cuando tenga que tomar la decisión de qué hacer en su TFG y con quién, sabiendo qué implica la elección de tutor y de línea de trabajo. Asimismo, nos permitirá a los docentes detectar de forma temprana aquellos alumnos con aptitudes hacia la investigación, permitiéndoles planificar su trabajo TFG con un enfoque que permita un máximo aprovechamiento de esa asignatura y, si fuese el caso, de su formación futura como investigador. Las actividades desarrolladas han incluido reuniones informativas sobre las actividades de la red, visitas guiadas a los laboratorios y realización de prácticas supervisadas en nuestros laboratorios. Con una población total de 43 alumnos, el 40 % ha mostrado interés por participar en parte de las actividades de la red y el 12 % ha optado por realizar todas las actividades propuestas, lo que se valora como unos porcentajes muy satisfactorios

Detección y estimulación temprana de la vocación científica en Química

El objetivo general de esta intervención educativa es dar al alumnado la oportunidad de tener una experiencia anticipada en tareas de investigación previa a la realización del TFG en química. Con esto se pretende que el alumnado disponga de un mejor criterio cuando tenga que tomar la decisión de qué hacer en su TFG y con quién, sabiendo qué implica la elección de tutor y de línea de trabajo. Asimismo, nos permitirá a los docentes detectar de forma temprana aquellos alumnos con aptitudes hacia la investigación, permitiéndoles planificar su trabajo TFG con un enfoque que permita un máximo aprovechamiento de esa asignatura y, si fuese el caso, de su formación futura como investigador. Las actividades desarrolladas han incluido reuniones informativas sobre las actividades de la red, visitas guiadas a los laboratorios y realización de prácticas supervisadas en nuestros laboratorios. Con una población total de 43 alumnos, el 40 % ha mostrado interés por participar en parte de las actividades de la red y el 12 % ha optado por realizar todas las actividades propuestas, lo que se valora como unos porcentajes muy satisfactorios