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In Situ Monitoring of Nanoparticle Formation during Iridium‐Catalysed Oxygen Evolution by Real‐Time Small Angle X‐Ray Scattering
Author(s) -
Singer Hobbs Maya,
Sackville Emma V.,
Smith Andrew J.,
Edler Karen J.,
Hintermair Ulrich
Publication year - 2019
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201901268
Subject(s) - small angle x ray scattering , iridium , catalysis , alkoxide , aqueous solution , scattering , nanoparticle , chemistry , amorphous solid , dynamic light scattering , particle (ecology) , materials science , chemical engineering , chemical physics , crystallography , nanotechnology , organic chemistry , physics , optics , oceanography , engineering , geology
Real‐time Small Angle X‐Ray Scattering (SAXS) has been used to investigate the homogeneity of a series of molecular iridium complexes during water oxidation catalysis in aqueous NaIO 4 solution through a continuous flow cell. The results obtained for the unstable [Cp*Ir(OH 2 ) 3 ] 2+ precursor forming amorphous IrO x nanoparticles (NPs) in‐situ validate and complement previous Dynamic Light Scattering (DLS) studies by providing enhanced sensitivity for small particle sizes and increased temporal resolution under realistic reaction conditions. Correlating particle formation profiles with O 2 evolution traces allowed homogeneous catalysis to be clearly distinguished from heterogeneous catalysis. A series of seven pyridine−alkoxide Cp*Ir complexes are shown to be fully homogeneous by SAXS, validating previous studies and confirming their catalysis to be molecular in nature throughout the reaction.