Ultra-thin Nb2O5 nanosheets construct 3D cross-linked architecture: Unraveling new coccine degradation pathways and toxicity changes

Abstract

Photocatalytic technology offers a promising approach to address environmental and health challenges posed by the food colorant new coccine (NC). Nb₂O₅ is a notable candidate due to its stability and environmental compatibility, but faces limitations such as limited active sites and rapid charge carrier recombination. In the present study, we report a novel Nb₂O₅ catalyst featuring a three-dimensional (3D) cross-linked architecture constructed from ultra-thin nanosheets, with a catalyst thickness of less than 2 nm. This innovative structure offers an eminent superficial surface area combined with a substantial abundance of active sites, making it an efficient photocatalyst for the degradation of NC. The Nb₂O₅ 3D catalyst demonstrated a remarkable degradation rate of 90.1 % for NC within just 30 min, accompanied by a rate constant of 73.5 × 10⁻³ min⁻¹. This performance significantly surpasses that of three alternative Nb₂O₅ catalysts with varying morphologies (nanorods, nanoparticles, and nanospheres), which show rate constants more than seven times lower. Furthermore, we explore the degradation pathways associated with NC and provide a thorough examination of the toxicity changes occurring in its by-products. This work presents a promising framework for the development of advanced catalysts capable of effectively degrading NC, thereby contributing to the advancement of environmentally sustainable practices in the management of food colorants.