High Efficient Photocatalytic Degradation of p-Nitrophenol on a Unique Cu₂O/TiO₂ p-n Heterojunction Network Catalyst

TLDR

p‑Nitrophenol is a persistent organic pollutant that resists degradation under solar light without strong oxidants. The Cu₂O/TiO₂ p‑n junction network, comprising Cu₂O nanowires on the nanotube surface and Cu₂O nanoparticles inside the TiO₂ nanotube walls, extends visible‑light absorption and promotes efficient separation of photogenerated carriers at the junction interface. Under artificial solar illumination, the Cu₂O/TiO₂ network degrades p‑nitrophenol at 1.97 µg min⁻¹ cm⁻², more than twice the rate of unmodified TiO₂ nanotubes (0.85 µg min⁻¹ cm⁻²).

Abstract

p-Nitrophenol (PNP) is a difficultly decomposed organic pollutant under solar light in the absence of strong oxidants. This study shows that under artificial solar light PNP can be effectively degraded by a Cu2O/TiO2 p-n junction network which is fabricated by anodizing Cu0 particles-loaded TiO2 nanotubes (NTs). The network is composed of p-type Cu2O nanowires on the top surface and Cu2O nanoparticles on the inner walls of the n-type TiO2 NT arrays. The Cu2O/TiO2 network shows much higher degradation rate (1.97 μg/min cm2) than the unmodified TiO2 NTs (0.85 μg/min cm2). The enhanced photocatalytic acitivity can be attributed to the extended absorption in the visible resulting from the Cu2O nanowire networks and the effective separation of photogenerated carriers driven by the photoinduced potential difference generated at the Cu2O/TiO2 p-n junction interface.