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

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.