ISSN 0036-0244, Russian Journal of Physical Chemistry A, 2014, Vol. 88, No. 10, pp. 1739–1743. © Pleiades Publishing, Ltd., 2014. Original Russian Text © M.N. Efimov, E.Yu. Mironova, E.L. Dzidziguri, G.N. Bondarenko, 2014, published in Zhurnal Fizicheskoi Khimii, 2014, Vol. 88, No. 10, pp. 1549–1553. 1739 INTRODUCTION Nanodiamonds have recently attracted interest from both theoretical and practical viewpoints. Their properties such as high surface area, thermal stability, and the presence of surface functional groups make them potentially useful in various fields of science and industry. Due to numerous functional groups on their surface, they can be effectively used as substrates for catalytically active particles after chemical modification of their sur- face with metals [1]. As is known, both NDs them- selves [2] and nanocomposites on their basis includ- ing particles of various metals are catalytically active. One of the important applications of metal– carbon nanocomposites with noble metal nanopar- ticles is their use as catalysts in chemical and petro- chemical processes [3]. As it is known [4], bimetalic particles possess better catalytic properties than monometal ones. It seems extremely important to create new methods for the synthesis of metal–carbon nano- composites based on NDs and to study their struc- ture to be able to control their properties. The goal of this study is to investigate the formation of plati- num group metal nanoparticles and their solid solu- tions in metal–carbon nanocomposites based on NDs. EXPERIMENTAL The metal–carbon composites were obtained under the conditions of infrared (IR) pyrolysis of the ND-based precursor and platinum, palladium, or ruthenium compounds. Nanodiamonds were prepared from the typical batch of detonation syn- thesis in a gas medium by thermooxidative purifica- tion followed by product separation from the aque- ous suspension by drying in convection driers (High Technologies Center, “Tekhnolog” special design office (SKTB), St. Petersburg). The precursor was prepared by dissolving metal compounds Pd(CH 3 COO) 2 (Aldrich, 99%) and PtCl 4 , RuCl 3 , or RhCl 3 (Aldrich, 99%) in dimethylformamide (DMF, Fluka, 99.5%); the Pt(Pd) : Ru(Rh) ratio was 9 : 1 or 7 : 3. Pyrolysis was performed in an IR chamber of a pulse photon annealing unit [5]. The IR annealing was performed in an inert atmosphere at 700°С. The basic annealing time was 2 min. The micrographs of the samples were obtained on a LEO912 AB OMEGA transmission electron micro- scope. The phase and structural studies were per- formed at room temperature on a DIFREY-401 dif- fractometer (Russia) (Cr K α radiation, Bragg–Bren- tano focusing). The results of experiments were treated by approximation and Fourier analysis [6]. For this study, we also used a method for calculating the Formation of Nanoparticles of Platinum Group Metal Alloys in Composites Based on Nanodiamonds M. N. Efimov a , E. Yu. Mironova a , E. L. Dzidziguri b , and G. N. Bondarenko a a Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, Russia b National University of Science and Technology (MISiS), Moscow, Russia e-mail: efimov@ips.ac.ru Received December 9, 2013 Abstract—Metal–carbon nanocomposites were synthesized from detonation nanodiamonds (ND) and plat- inum group metals under the IR pyrolysis conditions. The metal interacted with the nanodiamond surface. The size of metal nanoparticles was shown to depend on the amount of the metal introduced in the precursor. In ND/Pt–Ru, ND/Pt–Rh, ND/Pd–Ru, and ND/Pd–Rh nanocomposites, the metal phase was a solid solution. The lattice constants of the metal phases in the nanocomposites were determined. The quantity of the dissolved metal in the solid solution was evaluated. Keywords: metal–carbon nanocomposites, nanoparticles, noble metals, platinum, palladium, alloys, nano- diamonds, X-ray diffraction analysis. DOI: 10.1134/S0036024414100112 PHYSICAL CHEMISTRY OF NANOCLUSTERS AND NANOMATERIALS