“…The phases can be indexed as a mixture of RS Fm
m (JCPDS# 03‐065‐2901), wurtzite P 63 mc (ZnO, JCPDS#01‐076‐0704), tenorite C2/c (CuO, JCPDS#00‐041‐0254), and spinel Fd
m (Co 3 O 4 , JCPDS#01‐078‐1969) structures, which are commonly observed in starting powders of the RS:ESO synthesized via wet chemical routes
13,15,33 . These initial phases are consistent with the fact that Mg, Co, and Ni form RS oxides (being mutually soluble), whereas CuO and ZnO exhibit different crystal structures, presenting limited solubility in RS oxides
4,34,35 . Small intensity peaks are also detected at 2 θ = 4.95° and 5.70°, corresponding to the (1 1 1) and (2 0 0) Pt planes.…”