The transition to cleaner energy sources requires reducing the use of coal, oil and gas. One of the promising areas is the production of fuel from woodworking waste. The bio-oil obtained from them is a complex mixture, in order for such raw materials to become a full-fledged fuel, excess oxygen must be removed from it using a hydrotreating process, where metal catalysts play a key role.

Ruthenium is usually applied to a porous carrier by impregnation with salt solutions. However, metal particles tend to stick together and concentrate on the surface, which quickly reduces their activity.

Scientists from the Southern Federal University, together with colleagues from the A.V. Topchiev Institute of Petrochemical Synthesis of the Russian Academy of Sciences and Lomonosov Moscow State University, have proposed a simple method for obtaining ruthenium catalysts and X-ray diagnostics of the structure of active centers directly during the reaction.

The main method of their preparation is the impregnation of a porous carrier with solutions of metal salts. After removing the liquid, nanoscale ruthenium particles tend to stick together. Scientists have proposed a mechanochemical approach in which reagents are mixed without solvents. Ruthenium tricarbonyl was used as a metal source. As a result, the clusters evenly filled the pores of the carrier, and after heat treatment, a highly active material was obtained. Information about the structure of the catalyst at different stages of its preparation was obtained in situ at the Kurchatov synchrotron radiation source using a technique developed at the Southern Federal University.

Tests of the new catalyst in the hydrogenation reaction of guaiacol, one of the main components of wood bio-oil, showed its high efficiency: the activity of the catalyst turned out to be up to 60% higher than the samples obtained by the classical method, and the degree of purification of raw materials reached 100%. This activity is achieved due to the presence of active ruthenium centers in the catalyst, which were identified by X-ray radiation and evolved from Ru (CO)2 to the state of metallic nanoparticles during the reaction. Of particular importance is the discovered method for recovering spent catalysts. Treatment with synthesis gas, a mixture of carbon monoxide and hydrogen, at elevated temperatures and pressures leads to a decrease in the size of the ruthenium particles. According to the authors, a similar approach can be applied to nickel, iron, and rhodium-based systems.

"Such developments are a serious step forward in the field of environmentally friendly technologies and recycling of bio—raw materials. It is especially important that it was possible not only to increase the efficiency of the catalyst, but also to propose a method for its recovery, which makes the solution more sustainable and economically profitable. The contribution of the Southern Federal University team to the work consisted in X—ray diagnostics of the catalyst at various stages of its synthesis and operation, which made it possible to optimize the reaction conditions and propose new approaches to maintaining its activity for a long time," notes Alexander Guda.

 The results of the work carried out with the support of the Ministry of Education and Science of the Russian Federation are published in the Journal of Colloid and Interface Science. The INHS team of authors was supported by a grant from the Russian Science Foundation, and research on the Kurchatov synchrotron radiation source was carried out as part of a project by the Ministry of Education and Science (agreement 075-15-2025-509).