Cubic Cu2O nanoparticles decorated on TiO2 nanofiber heterostructure as an excellent synergistic photocatalyst for H2 production and sulfamethoxazole degradation

• Cubic Cu2O (20-−100 nm) synthesis on TiO2 nanofiber. • Cube-on-nanofiber showed excellent photocatalytic H2 production and sulfamethoxazole decomposition. • Surface modified TiO2 confirmed by the energy-resolved distribution of electron traps (ERDT). • Heterojunction interfaces between cube-on-nanofiber promote charge transfer and provide active sites. We report a simple strategy for providing a homogenous TiO 2 nanofibre host environment to stabilize Cu 2 O nanoparticles with an average size of ∼60 nm and high dispersibility. We found that the small fraction of Cu 2 O nanoparticles in direct contact/partially submerged with TiO 2 nanofibre arrays (diameter ∼300 nm and length ∼650 nm) showed excellent synergistic photocatalytic performance for H 2 production rate of 48 μmol g −1 h -1 with an apparent quantum efficiency of 3.6 %. The H 2 production rate was much higher (factor of ∼6.5 times) compared with unmodified TiO 2 -NF. In addition, the synergistic Cu 2 O/TiO 2 -NF photocatalyst showed significant oxidative-degradation of sulfamethoxazole (7 × 10 -2 mmol g −1 min -1 ) and was highly stable during five cycles. The small fraction of Cu 2 O nanoparticles are well dispersed and form heterojunction interfaces to promote charge transfer and provide active sites. This argument is verified by morphology characterisation, band alignment, energy-resolved distribution of electron traps, electrochemical transient photocurrent, and electrochemical impedance (EIS). In addition, a detailed discussion is provided regarding the surface and bulk elemental composition determined by X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), and X-ray absorption near edge structure (XANES).