{'fraction_non_alphanumeric': 0.02553191489361702, 'fraction_numerical': 0.020425531914893616, 'mean_word_length': 6.041916167664671, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Microstructural characterization of nanocrystalline gold particles supported on CoCr2O4

This work presents results of high‐resolution transmission electron microscope investigations of microstructure evolution of Au/CoCr2O4 catalyst subjected to various chemical treatments (reduction in hydrogen, reaction of propane oxidation and reaction of CO oxidation). Crystallites of CoCr2O4 support have octahedral or truncated octahedral shape and exhibit well‐developed faces, mostly (111). No change in the support morphology was noticed in catalyst samples after various chemical treatments. Small (∼8 nm) nanocrystals of gold supported on crystalline CoCr2O4 were observed for the fresh sample. The nanoparticles grow at the surface of CoCr2O4 as thin, disk‐like crystallites, in the preferred (111)Au∥(111)CoCr2O4 epitaxial orientation. Further treatment in hydrogen and in reaction conditions (CO and propane oxidation) did not change noticeably the size of Au particles, but modified slightly their shape. A main reason why Au particles retain small size despite heat treatment is their epitaxial contact with the CoCr2O4 support established during the catalyst preparation.