Ultrasonic cavitation enhanced photocatalytic CO2 reduction by superior flexible black BaTiO3 nanofibers

Photocatalytic CO 2 reduction is an attractive strategy to realize carbon–neutral economy but is challenging by its low efficiency and uncontrollable selectivity. Here, we report a new flexible black BaTiO 3 nanofiber (B-BTO NF) and prove its unique function of ultrasonic cavitation enhanced photocatalytic CO 2 reduction into controllable syngas. The B-BTO NFs with a large deformation ability and a high mechanical strength contain unsaturated Ti 3+ coordination and vacancy defects. Under ultrasound, the NF film gathers abundant cavitation bubbles, and the continual explosions of these bubbles bring periodic piezoelectric polarization changes and release net charges on B-BTO NFs, thus triggering photocatalytic CO 2 reduction into syngas. Moreover, the product selectivity can be controlled by facilely adjusting the ultrasonic frequency and power. As a result, the evolution rate of target syngas (CO/H 2  ≈ 1:1.3) reaches as high as 12525 μmol/g/h. The proposed flexible B-BTO NF induced ultrasonic cavitation-enhancement strategy provides new insights for designing photocatalysts.