Metallic nanoparticles for selective catalysis

C. Godard
Universitat Rovira i Virgili,
Spain

Keywords: nanoparticles, catalysis

Summary:

Over the last decades, transition metal-nanoparticles (M-NPs) have received a great deal of attention as catalysts since they potentially combine the advantages of heterogeneous and homogeneous catalysts. However, to date, the fine tuning of the properties of this type of catalysts to achieve specific selectivities remains a challenge. Ligands such as P-donors and NHC-carbenes were shown to efficiently stabilize metal nanoparticles[1] and some years ago, our research group reported in collaboration with the group of B. Chaudret and K. Philippot the synthesis of M-NPs (M= Ru, Rh, Ir) stabilized by chiral diphosphites and their application in the catalytic hydrogenation of arenes.[2,3] To gain understanding into the role and influence of the stabilizing ligands in catalysis, we recently synthesized a series of Rh-nanoparticles stabilized by phosphines, phosphites and NHC-carbenes and evaluated their catalytic performances in the selective hydrogenation of arenes[4] and aromatic ketones.[5] The results show that the nature of the ligand, its capacity and steric properties clearly influence the catalytic performances of the nanocatalysts. Furthermore, under D2 atmosphere, such nanoparticles are also able to selectively catalyse H/D exchange processes in P-based ligands, which provide new insights into the coordination of such ligands at their surface.[6] Metallic nanoparticles can also be used as models for classical heterogeneous catalysts to gain understanding in processes of industrial relevance such as Fischer-Tropsch Synthesis. Indeed, the utilization of well defined catalysts obtained from colloidal nanoparticles can provide information on various parameters that are difficult to analyse using classical catalysts. In this area, our group recently reported interesting effects of factors such as solvent, pH and particle size for this reaction using Co-nanocatalysts.[7] References: [1] A. Roucoux, J. Schulz, H. Patin, Chem. Rev. 102, (2002) 3757; D. Astruc, F. Lu, J.R. Aranzaes, Angew. Chem. Int. Ed. 44 (2005) 7852. [2] A. Gual, C. Godard, S. Castillon, C. Claver, Dalton Trans., 39 (2010) 11499. [3] A. Gual, C. Godard, K. Philippot, B. Chaudret, A. Denicourt-Nowicki, A. Roucoux, S. Castillón , C. Claver, ChemSusChem, 2 (2009) 769; A. Gual, R. Axet; K. Philippot, B. Chaudret, A. Denicourt-Nowicki, A. Roucoux, S. Castillon, C. Claver, Chem. Commun. (2008) 2759. [4] J. Llop Castelbou, A. Gual, E. Mercadé, C. Claver, C. Godard, Catal. Sci. Technol., 3 (2013) 2828; J. Llop Castelbou, P. Blondeau, C. Claver, C. Godard RSC Adv., 5 (2015) 97036. [5] J. Llop Castelbou, Emma Bresó-Femenia, Pascal Blondeau, Bruno Chaudret, S. Castillón, C. Claver, C. Godard ChemCatChem, 6 (2014) 3160. [6] E. Bresó-Femenia, C. Godard, C. Claver, B. Chaudret, S. Castillón Chem. Commun., 51 (2015) 16342. [7] J. A. Delgado, C. Claver, S. Castillón, D. Curulla-Ferré, C. Godard, ACS Catal. 2015, 5, 4568; Catal. Commun. 71 (2015) 88; Appl. Catal. A: General 513 (2016) 39.