Hierarchical N-doped TiO2@Bi2WxMo1-xO6 core-shell nanofibers for boosting visible–light–driven photocatalytic and photoelectrochemical activities

[Display omitted] •N-T@BWMO ternary composite with superior photocatalytic efficiency was first presented.•N-T@BWMO samples enhanced light-harvesting and reduced charge recombination rate.•Superoxide radicals and holes played major roles in tetracycline degradation process.•High photocatalytic activity was maintained after five cycles of reusability tests.•Photocatalytic mechanism for degradation of TC over N-T@BWMO was proposed. Heterogeneous photocatalysis has been proven to be a promising approach to overcome the great challenges encountered with conventional technologies for environmental remediation. Herein, for the first time, a novel hierarchical architecture of nitrogen-doped TiO2@Bi2WxMo1-xO6 (N-T@BWMO-x, x = 0–1.0) was rationally designed and fabricated through an electrospinning route followed by a solvothermal process. The photocatalytic activity of the as–prepared samples was evaluated based on the degradation of tetracycline hydrochloride (TC) under visible–light irradiation. The results indicated that the molar fraction of W/Mo has a strong impact on the photocatalytic efficiency and photoelectrochemical performance of the N-T@BWMO composites. Compared to N-TiO2 and the binary composites, N-T@BWMO-0.25 exhibited outstanding photocatalytic activity and significant cycling stability. The enhanced photocatalytic activity can be synergistically linked to the excellent native adsorption, extended light–harvesting region, hierarchical structure, and strong interfacial interaction between N-TiO2 and BWMO, which can effectively prolong the lifetime of charge-carriers. Moreover, active species-trapping and electron paramagnetic resonance results confirmed that holes and superoxide radicals were the dominant active species responsible for TC removal. A possible photocatalytic mechanism underlying the degradation of TC by N-T@BWMO-0.25 is also proposed. We expect that our findings will provide new insights into the use of highly efficient core–shell heterostructure photocatalysts, with potential applications in environmental decontamination.