Raman Spectroscopy: A New Approach to Measure the Percentage of Anatase TiO₂ Exposed (001) Facets

Abstract

Controlling the growth of high-activity anatase TiO2 exposed {001} facets improves greatly the adsorption and electronic and photocatalytic properties and has been attractive for various environmental and energy-related applications. In this paper, we introduced a novel approach for quantitatively measuring the percentage of exposed {001} facets in anatase TiO2 by using Raman spectroscopy. Comparing to XRD, Raman peaks originate from the vibration of molecular bonds, that is, vibrational mode Eg and A1g peaks, which are related to different crystal planes. Therefore, it provided a high sensitivity and accuracy for measuring the percentage of the exposed facets from the micro perspective of molecular bonding with less measurement errors. With the photocatalytic experiments, we found that 50% was the optimal percentage of the exposed {001} facets for the highest efficiency, which seemed more reasonable than the value of 70% obtained from XRD.