Defective photocatalysts

Various strategies have been developed toward enhancing the photocatalytic properties of materials. Of such strategies, defects’ creation has grabbed important attention as it often changes the properties of photocatalysts intrinsically, which means that the defective materials manifest properties akin to “inherent” properties of materials rather than “induced” properties. Defects tune several characteristics of photocatalysts, including the shifting of band edges, dispersion of energy bands, creation of charge-trapping centers, creation of surface catalytic sties, and surface sensitization. With these excellent abilities, defects have been demonstrated to enhance various applications of photocatalysis, including pollutant degradation, water splitting, CO2 reduction, N2 fixation, heavy metal reduction, and microbial disinfection. Accordingly, this chapter presents various types of defects, their origin, synthesis methods, formation mechanism, and the role of defects in enhancing the above-mentioned various applications of photocatalytic processes. Finally, it concludes by providing insights into further directions on the development of defective photocatalysts.