Facile one-step synthesis of cellular S-scheme N–ZnO/g-C3N4 toward boosted visible-light-driven CO2 reduction and norfloxacin degradation

Abstract

The construction of heterostructures for precise electron-transfer paths at the interface is crucial to widespread photocatalytic applications. In this context, we have implemented a simple one-step strategy to precisely transfer electrons from the conduction band of N-doped ZnO (N–ZnO) to the valence band of g-C₃N₄ by an S-scheme structure. The diverse structures and properties of the fabricated photocatalysts were synergistically verified using a series of characterization techniques. Notably, the direction of electron migration within this system was confirmed through X-ray photoelectron spectroscopy (XPS). The electrochemical impedance spectroscopy (EIS) demonstrated low charge transfer resistance, and photocurrent along with photoluminescence analyses showed enhanced spatial charge carriers separation capability of the heterostructures. Furthermore, the composite presented the cellular geometry and the long-term durability. These brought about the boosted photocatalytic performance for CO₂ reduction and norfloxacin (NOR) degradation. Specifically, the optimized composite containing 10 wt% N–ZnO (NZG-10) achieved a NOR degradation efficiency of 98.8% within 50 min, with a remarkable rate constant of 22.28 and 7.58 times that of N–ZnO and g-C₃N₄, respectively. Simultaneously, the NZG-10 was 2.98 times the CO yield of g-C₃N₄. This work offers valuable insights into developing methodologies to address the low light-harvesting capability of g-C₃N₄ and designing other novel structural materials with desirable photocatalytic performance for widespread applications in clean energy and eco-environment management.