In Situ Raman Probing of Chlorphenol Degradation on Different Facets of K3B6O10Br Single Crystal

Semiconductor photocatalysts with specific facets can induce high reactive activities has aroused wide attention. Here, we endeavor to gain quantitative insights into the intrinsic facet-dependent catalytic activities of K3B6O10Br (KBB) crystal using in situ Raman technique under room temperature by photocatalysis dechlorination of 2,4-DCP as a model reaction. Using a well-defined sizable KBB single crystal (size: 28 mm X 20 mm X 9 mm) with high (211), (110), and (101) facet exposure, the time-resolved Raman spectra for different facets have been clearly tested, it shows that the Raman spectrum of (211) facet had a remarkable change compared with (110) and (101) facets when the crystal was immersed in the 2,4-DCP solution under light irradiation. Through DFT, we obtain qualitative details on the reaction mechanisms of photocatalyzed and provide a refined understanding of the elementary processes. It was found that the -OH contact mode between the pollutant and the crystal facet was the most effective mode, which can produce more (OH)-O-center dot radicals than the other two modes. Moreover, the (211) facet offers the largest ratio of K atoms and surface energy, making the (211) facet more active than (110) and (101) facets.