Construction of core-shell heterojunction regulating α-Fe2O3 layer on CeO2 nanotube arrays enables highly efficient Z-scheme photoelectrocatalysis

Designing direct Z-scheme photocatalytic systems with core-shell architecture is crucial for effective charge separation towards sustainable photocatalysis. Herein, the core-shell heterojunction photocatalyst consisting of alpha-Fe2O3 nanoparticle layers encapsulating CeO2 nanotube arrays (Ce@Fe) was successfully synthesized through a simple and feasible strategy. The Ce@Fe heterojunctions exhibit the enhanced solar light scattering and absorption performance from 380 nm to 490 nm. The formed direct Z-scheme band structure between CeO2 and alpha-Fe2O3 further promotes the efficiency of carrier separation and transfer, and the core-shell nanotube array structure provides high specific surface area for antibiotic adsorption and enhanced light scattering, significantly improving the photoelectrocatalytic activity. Impressively, the unique photoelectrode achieves the highest pollutant removal efficiency of 88.6% for photoelectrocatalytic tetracycline degradation at 1 h under full light irradiation, and affords superior stability and strong alkaline resistance, which is expected to photoelectrocatalytic degrade antibiotics with high efficiency and environmental protection in harsh environment. Furthermore, the novel photoelectrocatalytic mechanism involving transfer behaviors of charge carriers, generation of reactive species, degradation intermediate products of tetracycline can be adopted after growing alpha-Fe2O3 layers onto CeO2 nanotube arrays, in accordance with direct Z-scheme mechanism.