Self-assembled iron (II) phthalocyanine modified oxygen vacancy-rich WO3 nanofibers with unique S-scheme heterojunctions for efficient tetracycline hydrochloride degradation and CO2 reduction

The advancement of efficient photocatalysts is crucial for the conversion of carbon dioxide (CO 2 ) into chemical fuels and wastewater treatment, due to the significant role in promoting energy sustainability and environmental remediation. In this work, we synthesized iron (II) phthalocyanine modified oxygen vacancy-rich (FePc/OVs-rich WO 3 ) photocatalyst with an S-scheme structure through electrospinning-calcination and electrostatic self-assembly. The optimized FePc/WO 3 –2 nanocomposite demonstrated approximately 3.69-fold enhancement in photoactivity for the conversion of CO 2 to CO and CH 4 , as compared with the OVs-rich WO 3 nanofibers. Furthermore, the FePc/WO 3 –2 catalyst demonstrated outstanding efficacy in activating peroxymonosulfate (PMS) for the degradation of tetracycline hydrochloride (TC), achieving an efficiency of 84.9 % within 60 min and a rate constant of 0.924 h −1 . The improved photocatalytic performance is attributed to the prolonged absorption of visible light, enhanced charge separation and the increased density of catalytic reaction sites. The enhancement in charge separation is predominantly linked to the unique S-scheme transfer process, which is characterized by non-overlapping optical absorption, in-situ X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT). This process is further facilitated by the catalytic activity of central Fe 2+ in FePc for the degradation of TC. The π-π interaction between FePc and the WO 3 nanofibers, which have a high concentration of oxygen vacancies, resulted in a fast electron transfer pathway, allowing efficient transport of photoelectrons. This paper comprehensively examines the advancement of high-performance S-scheme FePc/OVs-rich WO 3 photocatalysts for the photocatalytic reduction of CO 2 and degradation of tetracycline through the photo-assisted activation of PMS.