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 α-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 × 10−1 min−1) is about 17 times greater than that in the visible–Se NRs–HCl system with equal pH (1.0 × 10−2 min−1). Furthermore, we proposed a photocatalysis mechanism of the visible–Se NRs–H2O2 system based on electron paramagnetic resonance (EPR) characterization and studying the effect of different reactive species.