Catalysis
Analysis of bimetalic Fe-Ni catalists
HAADF image and EELS elemental maps of bimetallic Fe-Ni catalysts. We have studied the morphology and the metal chemical composition within individual nanoparticles with different ratios of the constituting transition metals. Iron oxidation at the surface of the catalysts has been put in evidence. This work has been done in collaboration with the MATCAT team of UCCS laboratory in the framework of the NobleFreeCat project supported by ANR (ANR-17-CE07-0022). Our colleagues have succeeded to create an innovative synthesis method of iron based bi-metallic particles with well-controlled morphologies and compositions as an alternative of the noble metal catalysts.
Maya Marinova (PMEL), Eric Marceau (MATCAT-UCCS), Anne-Sophie Mamede (MATCAT-UCCS), Jean-Sébastien Girardon (MATCAT-UCCS), Robert Wojcieszak (VAALBIO-UCCS), Sébastien Paul (VAALBIO-UCCS)
The formation of a mixed Mo-W sulfided phase in hydrotreating catalysts prepared from heteropolyanions as proven by HAADF imaging
New Mo and W based sulfide catalysts have been developed for the hydrotreatment of heavy oils. The use of mixed heteropolyanions (HPA), with Mo and W in the same molecular entity, as precursor of the active phase has led to more efficient catalysts than those prepared from a mixture of monometallic HPAs. High resolution HAADF analysis on the Titan Themis allowed to observe the sulfided slabs with atomic resolution and thus to evidence the presence of mixed Mo-W sulfided slabs in the case of mixed HPAs based solids (Figure (a)), whereas a mixture of monometallic slabs was observed on the other sample (Figure (b)). Moreover, the atomic distribution of atoms inside the slabs could be clearly observed, Mo atoms being surrounded by W ones in the mixed structure. (Nikulshina et al., 2018, Nikulshina et al., 2019, Nikulshina et al., 2020).
C. Lancelot (CEMOP-UCCS), M. Marinova (PMEL), C. Lamonier (CEMOP-UCCS), P. Blanchard (CEMOP-UCCS), P. Nikulshin (Samara State Technical University, Russia), M. Kulikiva (Samara State Technical University, Russia).
Synthesis of bimetallic Ni-Co nanoparticles onto mesoporous supports for advanced performances in catalytic applications
Deposition-precipitation is an effective method for the preparation of highly dispersed bimetallic Ni/Co nanoparticles (NPs) phases onto mesoporous siliceous support like SBA-15. The particle size, corroborated with the resistance to sintering and also the distribution of each metal within the support are the key factors to produce advanced materials which shows superior performances in catalytic application, detailed in our work is the hydrogenation of selected imines, oximes and N-heretoarenes. In this regard, the TEM FEI TITAN Themis 300 allowed us to precisely evaluate the dispersion and size distribution of the bimetallic NPs (Ciotonea et al., 2020).
Carmen Ciotonea (UPCAT - Institut Chevreul), Nisrine Hammi (MATCAT-UCCS), Jeremy Dhainaut (MATCAT-UCCS), Maya Marinova (PMEL), Adrian Ungureanu (Technical University Gheorghe Asachi, Iasi, Romania), Abdelkrim El Kadib (Universite Euro-Mediterraneenne de Fes, Marocco), Christophe Michon (Universite de Strasbourg, ECPM, France), Sébastien Royer (MATCAT-UCCS)