Joint research project

Au-based supported bimetal catalysts with non-noble metals (M = Cu, Zn and Sn) for the selective oxidation of cyclohexane: effect of the Au/M ratio, the structure and the support

Project leaders
Claudio Evangelisti, Ferenc Somodi
UNGHERIA - HAS (MTA) - Accademia Ungherese delle Scienze
CNR/HAS triennio 2019-2021 2019-2021
Chemical sciences and materials technology
Thematic area
Chemical sciences and materials technology
Status of the project
Report for renewal

Research proposal

Heterogeneous catalysis represents the key to ''green chemistry''. Indeed a decreasing pollution from chemical and refining processes can be forecasted by atomically tailoring the structure of active sites in order to convert reactants directly to products without generating by-products that typically end up as harmful emissions or as wastes. In particular of selective oxidation catalytic processes using molecular oxygen thus producing minimal by-product, are highly desirable in order to replace expensive and environmentally unfriendly stoichiometric reactions.
In this field the importance of structural features of metal nanoparticles and nanostructured systems to the performance of catalysts has stimulated wide efforts to develop methods for their synthesis and characterization, making this area of study an integral part of nanoscience.
The development of catalytic methods for the selectively oxidative functionalization of alkane carbon-hydrogen bonds remains a challenge in modern chemisty. The selective cyclohexane oxidation to cyclohexanone and cyclohexanol in aerobic atmosphere is key step for the production of valuable intermediates as adipic acid and caprolactam in nylon production process.
Au-based catalysis is an environmentally and economically viable process for producing a wide range of useful chemicals by selective oxidation reactions, as they can activate molecular oxygen and enable oxidation under mild conditions. Recently, Au catalysts were found to be able to effectively promote the reaction, withoutthe need for additional initiators. Furthermore, as the large international research activity on the field also demonstrated, the efficiency of gold can be enhanced by modification with a second metal and by proper choice of support. For understanding the role of different structural properties on activity, selectivity, stability, accidental inhibiting phenomena, and for optimization of the different parameters further systematic studies are needed. The proposed project is in line with all these.
Thanks to the previous joint research project (CNR/HAS 2016-2018), the Hungarian and Italian teams established a robust and fruitfull collaboration. According to the topic of the previous project, supported Au-Ag and Au-Cu bimetallic catalyst were studied and fully characterized. Gold-based bimetallic catalysts were synthesized by both SOL and solvated metal atoms deposition (SMAD) methods. The morphological and structural features of the bimetallic catalysts were effectively correlated with their catalytic behavior in selective alcohol oxidation (i.e. glycerol and benzyl alcohol). The shared experience and know-how led easily to beneficial effects in terms of publications and joint international conference communications. The reciprocal scientific skills are highly complimentary and strategically relevant in order to further enrich each team knowledge.
In the new joint project, the collaboration between the two groups will be consolidated in order to establish a long-term linkage. In order to complete the new issues raised from the previous joint project, the AuCu and AuAg systems would be exploited and new Au-based bimetallic systems will be investigated. In details, the role of the support in AuCu and AuAg bimetallic systems for the selective oxidation of glycerol will be investigated and new bimetallic and metal/metal oxide pairs will be sinthesized by SOL and SMAD methodologies.
New bimetallic catalysts pairing Au with not-noble metals such as Cu, Zn and Sn will be prepared with different internal metal ratio (0.1

Research goals

In the frame of the previous joint project, Hungarian and Italian teams shared very easily their experience in bimetallic Au-based catalysts with benefit for both of them, favoring a cross-fertilization and a fruitfull cooperation.
-The main task of the project is to produce a highly efficient and recyclable bimetallic Au-based catalysts for: i) selective catalytic oxidation of alcohol to targeted high-value products and ii) cyclohexane oxidation towards cyclohexanone and cyclohexanol products, using molecular oxygen as the oxidant. Indeed only the use of environmentally friendly oxidant could make the processes sustainable and alternative to stoichiometric or enzymatic processes.
-Another aim of the project is to establish a direct correlation between the bimetallic particle structures and composition and their activity/selectivity in dependence of the support and the substrate. This study will allow a wider application of the catalyst and promote design of new, targeted catalytic materials.
-At the same time, another relevant objective is to consolidate the established fruitfull collaboration between CNR-ISTM, Italy and MTA, Hungary. The topic of new joint project will extended to international collaborations leading to research project ideas and to apply for international or EU research grants.

Last update: 17/07/2024