Simple and low-cost colorimetric method for quantification of surface oxygen vacancy in zinc oxide.

Zinc oxide (ZnO) nanoparticles with surface oxygen vacancy (O) was found to catalyze the colorimetric reaction of 3,3',5,5'-tetramethylbenzidine (TMB)-HO, and the absorbance of this TMB-HO-ZnO system was strongly dependent the O concentration on surface of ZnO. By taking advantage of this phenomenon, one colorimetric method was proposed for quantifying surface O in ZnO. The surface O amount obtained through this colorimetric method matched well with that obtained through X-ray photoelectron spectroscopy (XPS). This colorimetric method doesn't need any advanced instruments, and can be completed in any an ordinary laboratory. This colorimetric method for detecting surface O amount was simple, rapid (about 15 min) and low-cost.