One-step solvothermal fabrication of Cu@PANI core-shell nanospheres for hydrogen evolution.

Polyaniline(PANI)-decorated Cu nanoparticles were prepared by a facile solvothermal method. Different reaction temperatures resulted in different morphologies of the Cu/PANI composites, which exhibited good photocatalytic activities. When the mass ratio of PANI increased to 2.5 wt%, the H2 evolution rate reached 1.97 mmol g-1 h-1 in lactic acid solution under solar light irradiation, which is about 2 times higher than that of pure Cu nanoparticles (1.06 mmol g-1 h-1). The introduction of PANI can improve the separation efficiency of the photo-generated electron-hole pairs, where PANI acts as a hole reservoir for trapping holes generated by the Cu NPs and hindering the recombination of the electron-hole pairs. A possible mechanism is presented to explain the photocatalytic process using Cu@PANI core-shell nanospheres as the photocatalyst.