Abstract
We investigated the structural evolution, atomic distribution, and alloying extent of mesostructured PtRu nanoparticles electrochemically reduced on microemulsion lyotropic liquid-crystalline (MLLC) templates on addition of heptane at varied concentrations using in situ small-angle X-ray scattering and in situ X-ray diffraction, complemented with X-ray absorption spectra and a transmission electron microscope. The structural stability of the MLLC template with heptane added is much improved compared to that of the corresponding LLC without alkane. For the duration of electrochemical reduction, a structural transition occurred from hexagonal to lamellar phase of MLLC templates when the heptane concentration was more than 8 wt %. With increasing heptane concentration, atomic distribution, and alloying extent, the CO tolerance factor of PtRu nanoparticles were considerably improved. The mesostructured PtRu nanoparticles produced on MLLC-directed templates with heptane at a concentration of 8 wt % show a structural morphology potentially applicable with superior catalytic activity in methanol electrooxidation. MLLC templates with alkane at varied concentrations enabled a convenient control over the nanopore size, alloying extent, and catalytic activity of mesostructured bimetallic nanoparticles. The complementary results provide new insight into the effect of heptane concentration on the structural evolution of mesostructured bimetallic nanoparticles with the use of templates of MLLC type. (Figure Presented).