Transition-metal doped titanate nanowire photocatalysts boosted by selective ion-exchange induced defect engineering

Defect engineering through elemental doping is an efficient way to boost the performance of semiconductor photocatalysts. Herein, transition-metal (TM) doped titanate nanowires (TNWs) were prepared via ion-exchange over the titanate precursors and demonstrated for the Rhodamine B (RhB) degradation under ultraviolet (UV) light irradiation. The ion-exchange of selective ions (V5+, Cr3+, Ni2+, and Zn2+) with protons from pristine TNWs resulted in the hierarchical meso-porosity of nanowires with large pores of similar to 5-20 nm by TM doping and small pores of similar to 3.6-4.5 nm inherited from pristine TNWs, which facilitates the mass transfer while maintaining high surface area and active sites. Meanwhile, the TM intercalation partially reduces the Ti4+ to Ti3+ and narrows the optical bandgap, which, together with oxygen vacancies and superoxide radicals from pristine TNWs, enhance the adsorption and photocatalytic degradation performance of RhB. This work helps to elucidate the effects of transition-metal doping and provides a rational strategy towards high performance titanate-based photocatalysts for efficient and sustainable wastewater treatment.

Automated summary

Defect engineering through elemental doping has been applied to enhance the photocatalytic performance of titanate nanowires (TNWs). In this study, transition-metal (TM) doped TNWs were prepared and demonstrated high efficiency in the degradation of Rhodamine B under UV light. The hierarchical meso-porosity of the nanowires, achieved by ion-exchange with selective ions, facilitated mass transfer while maintaining high surface area and active sites. TM intercalation reduced Ti4+ to Ti3+, narrowed the optical bandgap, and enhanced the adsorption and photocatalytic degradation of RhB. This work provides insights into the effects of transition-metal doping and offers a rational strategy for the development of high-performance titanate-based photocatalysts.