Herein, tetragonal tungsten bronze-type oxide KSr2Nb5–xTaxO15 (KSNT) catalysts with a rod-shaped structure were synthesized by a molten salt method and their tribocatalytic and antimicrobial activities characterized. A simple and cost-effective acid treatment generated surface defects to enhance the catalytic activity. The enhanced tribocatalytic activity with a degradation efficiency of 94.8% of RhB within 90 min and a rate of 0.035 min–1 was obtained in the sample x = 1 compared to the literature in which similar values were observed at 360 min. In addition, for the first time, the viability of Escherichia coil and Staphylococcus aureus was investigated, and values of 11.2 and 15.1% were achieved within 90 min, respectively. The enhanced catalytic activity was contributed by more exposed oxygen vacancies on the surface of KSNT nanorods. This suggests that KSNT is an effective bifunctional catalyst with dye degradation and antibacterial inhibition activities.