Hierarchical nitrogen doped bismuth niobate architectures: Controllable synthesis and excellent photocatalytic activity

► N-Bi3NbO7 architectures were synthesized via two-step hydrothermal process. ► Electronic structure calculations indicated that N replaced O in samples. ► Growth mechanism is proposed for transformation of nanoparticles to microflowers. ► Excellent activities of N-Bi3NbO7 architectures were obtained for degradation. ► Enhanced photocatalytic performance was observed for Ag/N-Bi3NbO7 architectures.