| Summary: | Herein, we report a one-dimensional (1D) S-doped K<sub>3</sub>Ti<sub>5</sub>NbO<sub>14</sub>@TiO<sub>2</sub> (STNT) core-shell heterostructured composite with an enhanced photocatalytic degradation activity under visible light, which was prepared by a simple reassembly-calcination method using thiourea as the S source. The anisotropically shaped rods are favorable for the rapid transport of photogenerated charge carriers. The substitution of Ti<sup>4+</sup> by S<sup>6+</sup> is primarily incorporated into the lattice of the TiO<sub>2</sub> shell so as to create an intra-band-gap state below the conduction band (CB) position, giving rise to Ti−O−S bonds and thus the visible light response. The presence of electron-deficient S atoms is of benefit to the decreased recombination rate of photogenerated electrons and holes by capturing electrons (e<sup>−</sup>). Meanwhile, a tight close interface between K<sub>3</sub>Ti<sub>5</sub>NbO<sub>14</sub> and TiO<sub>2</sub> was formed to achieve a nano-heterojunction structure, leading to the fostered separation of its interfacial photogenerated electrons and holes. The visible-light-driven photocatalytic degradation of methylene blue (MB) by STNT composites is higher than that by pure K<sub>3</sub>Ti<sub>5</sub>NbO<sub>14</sub>, owing to the synergistic effects of S doping and heterojunction. A possible photocatalytic mechanism was proposed with a reasonable discussion. This work may provide an insight into constructing highly efficient core-shell photocatalysts used toward sustainable environmental remediation and resource shortages.
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