Hollow bi-Janus hetero-nanofibers as a bi-functional photoreforming catalyst for prominently boosting hydrogen evolution from water-pollutant system

Bi-functional photoreforming catalysts are promising for synergetic hydrogen evolution and pollutant removal through a water-pollutant system. The rational energy band and interface engineering are crucial in promoting their performance but are still challenging due to finely regulating nanoscale interface difficulties. Herein, single to bi-Janus interface engineering is adopted to develop hollow bi-Janus SrTiO₃/ZnO/TiO₂ hetero-nanofibers with gradient energy band and spatially separated redox surfaces via electrospinning married atomic layer deposition methods. The simulations indicate that these novel structures have a stronger internal electric field (5.72 ×10⁶ V/m) than SrTiO₃/ZnO (1.84 ×10⁶ V/m) and ZnO/TiO₂ (3.98 ×10⁶ V/m) single-Janus hetero-nanofibers (SJ-HNFs), and more ordered electric field distribution than mixed hetero-nanofibers (MHNFs). Experimentally, they have better charge separation and directional carriers transfer path, as evidenced by photoluminescence, photovoltage, and photoelectrochemical investigations, along with photo-deposition probe experiments. The gradient energy band, directional charge transfer path, and spatially separated redox surfaces promote their photoreforming performance effectively, presenting a high photoreforming hydrogen evolution rate of 104.6 μmol g⁻¹ h⁻¹ in 10,000 ppm propranolol (corresponding degradation of 33.1% after 5 h), about 3.62, 4.27, and 3.11 times of ZnO/TiO₂ SJ-HNFs, SrTiO₃/ZnO SJ-HNFs and SrTiO₃/ZnO/TiO₂ MHNFs. This work provides a promising interfacial engineering strategy for designing photoreforming catalyst to simultaneously achieve energy conversion and environmental pollution treatment.