Nanoscale Intimacy in Heterogeneous Catalysis – INCH

Usually, the two functions of a bifunctional catalyst are randomly distributed and its catalytic properties are maximized varying their respective amounts to get the so-called ‘ideal balance’. Such approach does not explicitly consider the distance between the two functions. The only condition is to respect the Weisz criterion providing the maximal distance between two types of active sites, above which the cooperative effect becomes null. However, this criterion concerns the micrometric scale but does not take into account the role of atomic and nanometric intimacy on selectivity. This role is rarely considered in the literature and suffers from a lack of quantitative data.
Therefore, the main objectives of the INCH project are to better understand the effect on selectivity of the density of contact (in touch intimacy) and of the distance between two functions (nanoscale intimacy) of a bifunctional catalyst from quantitative data and to define new intimacy criteria.The INCH project will be focused on the direct conversion of syngas to lower olefins by the SDTO and OX-ZEO processes over (Cu/ZnO, SAPO-34) and (ZnCr2O4, SAPO-34) bifunctional catalysts , respectively. These processes are good candidates since the intermediates formed on the hydrogenating function (methanol and ketene over Cu/ZnO and ZnCr2O4, respectively) have to diffuse to the acidic function (SAPO-34) to form olefins.
To reach these goals, a consortium including researchers, engineers and technicians of three French laboratories (IRCELYON, IC2MP, LGPC) have been constituted. This consortium convers all the skill chain of heterogeneous catalysis: catalysts design & preparation, characterization including in situ/operando measurements, catalytic properties and macro/micro kinetics, chemical engineering.
The work methodology includes:
- The management by the coordinator,
- The study of in touch intimacy by preparing and characterizing catalysts for which the density of contact will be modulated,
- The study of nanoscale intimacy by preparing and characterizing catalysts for which the distance between the two functions will be modulated,
- The quantification of intimacy by several techniques such as electronic microscopies, H2 chimisorption, hydrogenation of unsaturated amines and FRET spectroscopy,
- Measurements of catalytic properties and kinetic data (heats of adsorption, diffusion coefficients)
- A kinetic modelling and 2D/3D modelling leading to define new intimacy criteria.
To achieve the work program, a financial support of 492.7 keuros is requested from ANR. It includes the funding of a PhD student (36 months), two post-doc researchers (18 months each) and trainees to reinforce the manpower of the consortium.
The scientific approach of the INCH project is fundamental which accounts for the choice of the PRC program. It is relevant to Challenge 3 because the development of more sustainable route to produce light olefins is key issue for the industrial renewal. Generally speaking, it aims at designing very selective catalysts and the methodology can be transposed to other bifunctional reactions of refining (hydroisomerisation/hydrocracking, selective ring opening) or bio-refining (hydrodeoxygenation, oxydehydration).
The INCH project will generate numerous fundamental results (quantification of intimacy for two types of catalysts, kinetic data, new intimacy criteria,...) and applied data (catalytic performances for the SDTO and OX-ZEO processes). Some of them are very original (hydrogenation of unsaturated amines, FRET, RF-IGC,…). The valorization strategy is to publish the results in high-impact scientific journals and to communicate widely in national and international congresses.