Synthesis and Study of Catalytic Activity in Propane Steam Reforming of Ru–Cu and Ru–Ni Alloy Nanoparticles with Compositions in the Miscibility Gap by Thermolysis of the [RuNO(NH3)4OH][M(C2O4)2(H2O)n], M = Cu, Ni

Abstract

Complex salts [RuNO(NH3)4OH][M(C2O4)2(H2O)n] (M = Cu, Ni)─the precursors of nanoalloys combining ruthenium and copper/nickel─were prepared. Thermal properties of the prepared salts were examined in different atmospheres. Thermal decomposition of the precursor in an inert atmosphere was thoroughly examined and the intermediate products were characterized. Experimental conditions for preparation of copper-rich (up to 16 at % of copper) metastable solid solution CuxRu1–x (based on Ru structure) and ruthenium-rich (up to 33 at % of ruthenium) metastable solid solution CuxRu1–x (based on Cu structure) were optimized, which is in sharp contrast to the bimetallic miscibility gap known for the bulk counterparts in a wide composition range. The catalytic activity of supported bimetallic catalysts Cu–Ru/CZ and Ni–Ru/CZ, as well as the monometallic catalyst Ru/CZ, in the propane steam reforming reaction was studied. It is shown that the Ni–Ru/CZ sample is an optimal catalyst for the propane prereforming process compared to the monometallic ruthenium sample at T = 200–500 °C. Cu–Ru/CZ exhibits lower activity but greater selectivity for hydrogen at 200–350 °C. Using a two-stage kinetic scheme, mathematical modeling of the kinetics of the process of steam reforming of propane was carried out for the most promising catalyst Ni–Ru/CZ.