Insufficient knowledge on multiple processes at the interface of different phases of one-dimensional titanium dioxide (1D TiO2) photoanodes hinders the efficiency of solar-powered hydrogen production in a photoelectrochemical cell. Density functional theory (DFT) and experimental studies were performed to identify the interface characteristics of the heterojunction formation between 1D TiO2 (0 1 1) surface and graphene quantum dots (GQDs) for the enhancement of photocatalytic hydrogen production. The interfacial electronic structure, charge transfer, and optical characteristics of the GQD@TiO2 rutile (0 1 1) � 2 � 1 surface were simulated and experimentally validated using Hubbard modified generalised gradient approximation (GGA + U). Both theoretical and experimental results confirmed the extension of optical absorption into the visible range and frequent charge transfer from GQD to the TiO2 rutile (0 1 1) surface, facilitating electron-hole separation and reducing charge recombination rate. Furthermore, the formation of highly crystalline TiO2 rutile (0 1 1) nanorods with uniform distribution of GQDs was validated through X-ray diffraction (XRD) and transmission electron microscopy (TEM) results. The hydrogen production rate over GQD@TiO2 rutile (0 1 1) photoanode was 31063 µmol g�1 h�1, nearly five times more efficient than the pristine TiO2 rutile (0 1 1). Also, a mechanism for photogenerated electron transfer and energy-band-matching at the hybrid interface was proposed. © 2021