Defective Dopant-Free TiO2 as an Efficient Visible Light-Active Photocatalyst

Pristine and modified/doped titania are still some of the most widely investigated photocatalysts due to its high activity, stability, abundance proper redox properties carry out various reactions. However, modifiers and/or dopants resulting in visible-light activity might be expensive or work as recombination centers under UV irradiation. It seems that defective titania, known “self-doped” TiO2, best solution since it can obtained mild conditions without addition materials methods. This review discusses methods preparation, characterization defect types, their localization (surface vs. bulk) function, well proposed mechanisms photocatalytic reactions presence self-doped titania. Although many kinds samples have already been prepared with different colors, color intensities (mainly Ti3+ oxygen vacancies), is difficult conclude which them recommended preparation testing used by authors differ. Furthermore, solar radiation for dyes does not clarify mechanism bare also excited sensitized, respectively, these conditions. In reports, considered possible influence impurities originated from synthesis method (e.g., H, Al, Zn, Cl, F) could co-participate overall Moreover, reports indicate especially black ones, decrease defects centers. Despite unproven/unclear findings unanswered questions, there well-conducted studies confirmed both experimental theoretical a promising material Based on available literature, optimal defects’ concentration, preferential role surface defects, higher surface-to-bulk ratio rutile than anatase, beneficial impact disordered important aspects during