Flower-like 3D CuO microspheres were synthesized and used to photo-catalyze water oxidation under visible light.The structure of the CuO microspheres was characterized by scanning electron microscopy,transmission electron microscopy,infrared,powder X-ray diffraction,electron dispersive spectroscopy,Raman and X-ray photoelectron spectroscopy（XPS）.This is the first time that a copper oxide was demonstrated as a photocatalytic water oxidation catalyst under near neutral conditions.The catalytic activity of CuO microspheres in borate buffer shows the best performance with O2 yield of 11.5%.No change in the surface properties of CuO before and after the photocatalytic reaction was seen by XPS,which showed good catalyst stability.A photocatalytic water oxidation reaction mechanism catalyzed by the CuO microspheres was proposed.
Two polypyridine complexes containingμ‐OH,μ‐O2dicobalt(III)cores,[(TPA)CoIII(μ‐OH)(μ‐O2)CoIII(TPA)](ClO4)3and[(BPMEN)CoIII(μ‐OH)(μ‐O2)CoIII(BPMEN)](ClO4)3(TPA=tris(2‐pyridylmethyl)amine,BPMEN=N,N′‐dimethyl‐N,N′‐bis(pyridin‐2‐ylmethyl)ethane‐1,2‐diamine),have previously been reported as inactive in the light‐driven water oxidation reaction(ACS Catal.,2016,6,5062?5068).Herein,another dicobalt(III)compound,μ‐OH,μ‐O2‐[{(enN4)2Co2}](ClO4)3(enN4=1,6‐bis(2‐pyridyl‐2,5‐diazaocta‐2,6‐diene),with a similar core structure was synthesized,characterized,and applied to the light‐driven water oxidation reaction.Collective experiments showed that the complex itself was also inactive in the light‐driven water oxidation,and that the activity observed originated from Co(II)impurities.This research establishes that complexes possessing aμ‐OH,μ‐O2dicobalt(III)core structure are not appropriate choices for true molecular catalysts ofwater oxidation.
