TiO2 single-crystal nanomaterials with highly reactive
surfaces have attracted widespread attention due to their fundamental
aspects and industrial applications. However, many previous studies
have ignored the poor photoelectric efficiency of TiO2 nanomaterials
originating from a mismatch in the diffusion distance of electrons
and holes as well as migration rates of holes and electrons. Therefore,
suppression of hole migration could enhance the photoelectrochemical
performance of TiO2. In this work, single-crystal anatase
TiO2 nanomaterials with (001) facets were successfully
prepared. The results suggested that some (101) facets were retained
by the modified fluoride ion crystal facet control process. Subsequently,
fluorine-free and Au-containing crystal facets were obtained by annealing
and electrochemical deposition. In addition, the propensity for adsorption
of Au on a TiO2 (101) surface was verified by first-principles
quantum chemical calculations. Electrochemical impedance spectroscopy
and UV–visible spectrophotometry showed the presence of a large
area (001), conducive to better enzyme affinity. Biosensors prepared
by carrier self-separation derived from natural different facets and
Au nanoparticles (TiO2 (001)/Au/GOx) achieved high sensitivities
reaching 16.86 μA mM–1 cm–2, an extended linear range (0.01–3 mM), and a low detection
limit (0.83 μM). In summary, the proposed route allowed for
the first time the use of nanocrystal engineering in the construction
of glucose biosensors with satisfactory performances, which is promising
for the future fabrication of high-performance biosensors.