Crystal facet-engineering has become a promising approach to improve photocatalytic activity in various areas. Although photocatalysis for water disinfection using solar energy continues to attract research interest, limited research has been conducted on the application of crystal facet-engineering in this field. In this study, Cu/TiO₂ nanorods with small, middle, and large aspect ratios were synthesized through crystal facet-engineering, and their antimicrobial activity was confirmed. Cu/TiO₂ nanorods with a high aspect ratio exhibited a high inactivation rate of 0.42 log inactivation/min against phix174 under visible light illumination, which was about 11.8-fold higher than that of Cu/TiO₂ with a small aspect ratio. Systematic investigations revealed that introducing Cu on the (110) facet of TiO₂ increased the photocatalytic performance, as confirmed by the diffuse reflectance spectra, photo-induced current density, electrochemical impedance, and photoluminescence spectra. Microbial disinfection efficiency can be effectively improved by selectively depositing Cu on the TiO₂ (110) facet to control the redox reaction of Cu. This study provides deep insights into the development of efficient antimicrobial nanomaterials through the synergistic effect of spatial charge carrier separation induced by crystal facet-engineering and the control of subsequent oxidation-reduction reactions by loading a co-catalyst on a specific facet.