Herein, a C atom-doped ZnO solid solution (C-ZnO SS) nanocatalyst with excellent photocatalytic activity was successfully synthesized by a one-step combustion method. The deposition of C dots on the surface and the doping of C atom into the ZnO crystal were realized simultaneously. The sucker effect between C dots and C-ZnO SS in the nanocatalyst was found. A large surface area, increased crystal defect, and enhanced separation of photo-generated carriers brought about a high degradation rate for naphthalene and anthracene. The complete degradation time of unmanageable polycyclic aromatic hydrocarbons was only several hours when C-ZnO SS was used as a nanocatalyst. In addition, a positively correlated conclusion about the degradation rate and the electron density of benzene rings was proposed. This research provides a new nanocatalyst for the degradation of unmanageable pollutants in the environment.