Visible-light-responsive t-Se nanorod photocatalysts: synthesis, properties, and mechanism

One-dimensional (1D) single-crystalline trigonal selenium nanorods (t-Se NRs) were prepared through a solid-solution-solid method by dispersing the prepared amorphous alpha-Se spheres in ethanol. The single crystal structure of the t-Se NRs could be excited under visible light, with a band gap of 1.56 eV. The t-Se NRs were found for the first time to display noticeable photocatalytic activity under visible light. In addition, the rate of photodegradation of methyl orange (MO) in the visible-Se NRs-H2O2 system (1.7 x 10(-1) min(-1)) is about 17 times greater than that in the visible-Se NRs-HCl system with equal pH (1.0 x 10(-2) min(-1)). Furthermore, we proposed a photocatalysis mechanism of the visible-Se NRs-H(2)O2 system based on electron paramagnetic resonance (EPR) characterization and studying the effect of different reactive species.