Novel photocatalyst nitrogen-doped simonkolleite Zn5(OH)8Cl2•H2O with vis-up-conversion photoluminescence and effective visible-light photocatalysis

As photocatalysts exhibit selectivity toward various pollutants, it is necessary to develop different and novel photocatalysts. In this work, a novel photocatalyst-nitrogen-doped simonkolleite Zn-5(OH)(8)Cl2H2O (DSM) is prepared through a new facile method: calcinating the mixture of zinc hydroxide, urea, and guanidine hydrochloride at 575 degrees C for 1h in a furnace with an air atmosphere. The as-prepared sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectra, UV-visble near-infrared diffuse reflection spectra (UV-Vis-NIR DRS), Brunauer-Emmett-Teller (BET) method, Ramen spectra and Zeta potential measurement, photocatalytic properties, as well as active species trapping experiments. XRD and XPS show the as-prepared powder is nitrogen-doped simonkolleite Zn-5(OH)(8)Cl2H2O (DSM) with a small ZnCl2 fraction. SEM investigation indicates that the as-prepared powder possesses a flower-like layered shape. The UV-Vis-NIR exhibits that after doping, the DSM possesses strong light absorption in the ranges of 300-500 and 1400-2500nm, a direct electronic transition with a band gap energy of 2.469eV. PL measurement reveals a strong photoluminescence and an up-conversion from lower to higher-energy visible light in as-prepared samples. Zeta potential investigations show that during photocatalysis, the charges on as-prepared photocatalyst are positive. The photocatalytic experiments show a good dark adsorption, a high photodegradation (99.4% at 60min), a high pseudo-first-order constant (k) of 0.0261min(-1). Meanwhile, the active species trapping experiments suggest that hole (h(+)) is the dominant active species during photocatalysis. It is concluded that the doping favors in enhancing vis-light-photocatalysis. This work makes a significant contribution to the literature.