Ternary core-shell heterostructured rutile@anatase@Crx Oy nanorod arrays were elaborately designed as photoanodes for efficient photoelectrochemical water splitting under visible-light illumination. The four-fold enhanced and stabilized visible-light photocurrent highlights the unique role of the interim anatase layer in accelerating the interfacial charge transfer from the Crx Oy chromophore to rutile nanorods.