Fabrication of High-Performance TiO2 Nanofibers on Coconut Shell Activated Carbon Particles for Photocatalytic Degradation of Organics in Marine Environment

This study aims to overcome the limitations of powder catalysts in the photocatalytic degradation of organics in a marine environment. To achieve this, coconut shell activated carbon (AC) particles were utilized as a carrier to grow Ti(OH)4 nanofibers. Er3+ and Yb3+ ions were introduced into the nanofibers through ion permeation, solving the problem of preparation caused by the mismatch of ionic radii and enhancing the utilization of infrared light in the solar spectrum. The results of photocatalytic degradation in seawater demonstrated that Er3+-Yb3+ in the lattice enhanced the photocatalytic activity more effectively than supported Er2O3-Yb2O3. Additionally, during the calcination process, more oxygen vacancies (OVs) were conveniently introduced into TiO2 through self-generated CO, further improving the separation of excited electron–hole pairs. The introduction of more OVs exhibited significantly higher generation rates and steady-state concentrations of 1O2 and •OH in seawater. Quenching experiments revealed that the presence of 1O2, •OH, holes, and O2•– all contributed to the degradation efficiency with their relative contributions depending on the specific compound. The AC-supported high-performance TiO2 nanofibers display great potential for applications in the photocatalytic degradation of organics in a marine environment.