Atomic Molybdenum\nDispersed on Graphitic Carbon Nitride\nNanosheets for Photocatalytic Degradation of Antibiotics

High-performance\nphotocatalysts are being intensively\npursued for\nenvironmental remediation. In this work, atomic molybdenum (Mo) dispersed\ng-C<sub>3</sub>N<sub>4</sub> (Mo/CN) photocatalyst was obtained via\na three-step preparation process containing direct calcination, microwave\nhydrothermal treatment, and recalcination. Mo/CN displays a configuration\nof atomic Mo in-plane coordination with two N atoms of g-C<sub>3</sub>N<sub>4</sub> in the big loop. A remarkable augmentation of specific\nsurface area and construction of the amorphous–crystalline\ninterface of Mo/CN are achieved. The specific surface area of the\nMo/CN sample is ca. 1.8-fold of g-C<sub>3</sub>N<sub>4</sub> without\nMo incorporation (m-CN) and 7.7-fold of pristine g-C<sub>3</sub>N<sub>4</sub> (p-CN), respectively. The introduction of Mo single atom\nnarrows the energy band of g-C<sub>3</sub>N<sub>4</sub>, slows down\nthe combination of photogenerated carriers, and promotes the adsorption\nof O<sub>2</sub> molecules over g-C<sub>3</sub>N<sub>4</sub>. The\noptimal Mo/CN-0.075 exhibits an enhanced photocatalytic activity toward\nantibiotics with a removal efficiency of tetracycline reaching 92.1%,\nhigher than m-CN (74.0%) and p-CN (50.8%) as well as most of the other\nreported g-C<sub>3</sub>N<sub>4</sub>-based photocatalysts. Active\nspecies <sup>•</sup>O<sub>2</sub><sup>–</sup> and <sup>1</sup>O<sub>2</sub> play a dominant role in the photocatalytic removal\nof the antibiotics. The growth experiment of hemp peas and treatment\nof local printing and dyeing wastewater show a possible real-world\napplication of Mo/CN-0.075. This work offers some insights into the\nimprovement of g-C<sub>3</sub>N<sub>4</sub>-based photocatalysts with\nhigh surface area and tailored electronic properties for efficacious\nwastewater treatment.