Efficient and stable photocatalytic degradation of PET waste textiles through Ni2P–Cu3P/TiO2/C NFs facilitated by the synergistic effect of CTAB and p–n heterojunctions

Abstract

With the rapid development of the textile and plastic industries, non-degradable polyester fibers have become one of the major environmental and resource issues globally. In this study, we prepared a p–n heterojunction Ni₂P–Cu₃P/TiO₂/C nanofiber (NF) photocatalyst through a combined technique using electrospinning, carbonization, hydrothermal treatment, and phosphorylation. The Ni₂P–Cu₃P/TiO₂/C composite nanofibers exhibit excellent light absorption capacity across the entire optical spectrum. Also, the layered structure of Cu₃P–Ni₂P facilitates the reflection of light between the surfaces of the fibers, enhancing light absorption. The coupling of Ni₂P and Cu₃P establishes a P–N heterojunction at the photocatalytic interface, promoting the separation of charge carriers, suppressing the recombination of charge carriers and extending the lifetime of charges. Accordingly, the Ni₂P–Cu₃P/TiO₂/C NFs demonstrated excellent photocatalytic performance. During photocatalytic degradation of PET waste textiles, the hydrogen evolution amount reached 206.6 μmol_H2 g_Sub⁻¹ after 48 hours, with a weight loss rate of 15% in polyester fibers. Impressively, the addition of CTAB during the catalysis process increased the hydrogen evolution amount to 321 μmol_H2 g_Sub⁻¹, which is 1.5 times higher than that without CTAB. Meanwhile, the weight loss rate of polyester fibers reached 18%. This confirms the feasibility of CTAB in enhancing the photocatalytic degradation of PET fibers. Furthermore, it is easy to separate and recover the catalyst from the solution, maintaining stable hydrogen production performance even after multiple cycles. This work provides a low-cost strategy for the rational design of efficient and recyclable composite photocatalysts, offering a pathway for the recycling of polyester waste.