One-Pot Synthesis of Ru-Doped ZnO Oxides for Photodegradation of 4-Chlorophenol

Abstract

The photocatalytic degradation of 4-chlorophenol in water using Ru-doped ZnO mixed oxides (0, 0.5, 1, and 3 wt% RuO2) synthesized by the one-pot homogeneous coprecipitation method is reported. ZnO with wurtzite structure was present in the mixed oxide as corroborated by Raman spectroscopy and X-ray diffraction analysis. All the samples showed nanorod morphological features. The presence of Ru6+/Ru4+ couples on ZnO modified the band gap of the mixed oxides and led to a shift of the band gap energy from 3.20 eV to 3.07 eV. Ru addition increased the surface area and significantly promoted the formation of active surface oxygen species such as hydroradicals evidenced by the fluorescence spectroscopy measurement. In the photodegradation of 4-chlorophenol solution under UV irradiation, a notable increase in photoactivity was obtained as the amount of RuO2 in the mixed oxides increased to 3 wt%. The charge transfer between Ru6+/Ru4+ couples and ZnO nanoparticles together with the formation of free radical oxidant species effectively inhibits electron-hole recombination rate, thus favoring the photodegradation of 4-chlorophenol.

Photocatalytic Removal of Methyl Orange Azo Dye with Simultaneous Hydrogen Production Using Ru-Modified ZnO Photocatalyst

“…The addition of Ru did not induce changes in the crystalline structure of ZnO. This last result is consistent with the literature concerning Ru-modified ZnO [27]. In addition, no signals related to metallic Ru or ruthenium oxides were observed for 0.1 and 0.25 Ru mol%.…”

“…After the doping of the ZnO with Ru, an improvement in the intensity of light absorption in the UV region was observed. All the Ru-modified ZnO samples evidenced a continuous absorption in the visible range and the absorption was stronger with the increase of Ru content [27]. This last result may be explained considering the fact that undoped ZnO appears as a white powder, while the modification with ruthenium turns the samples into dark green colour, which is more pronounced at a higher Ru concentration [33].…”

Rational design of porous Ru‐doped CuO nanoarray on carbon cloth: Toward reversible catalyst layer for efficient Li‐O 2 batteries

“… 32,33 Also, as shown in Figure 4C, the peaks assigned to Ru 4+ and Ru 6+ appear in the Ru 3d spectrum of Ru‐CuO/RuO 2 @CC, indicating that they are consistent with the Ru 3p spectrum. Ru related peaks appear to be related to RuO 2 attached to the CC surface as well as Ru‐CuO nanorods 33 . To investigate the Ru doping relevance of Ru‐CuO nanorods, it is considered appropriate to examine the O 1s spectrum.…”

“…31 As for the Ru 3p 3/2 spectrum of Ru-CuO/RuO 2 @CC, 462.7 and 464.9 eV are matched with Ru 4+ from RuO 2 and Ru 6+ from RuO 3 , respectively (Figure 4B). 32,33 Also, as shown in Figure 4C, F I G U R E 2 X-ray diffraction (XRD) diffraction patterns of (A) Ru-CuTCNQ/Ru@CC and (B) Ru-CuO/RuO 2 @CC the peaks assigned to Ru 4+ and Ru 6+ appear in the Ru 3d spectrum of Ru-CuO/RuO 2 @CC, indicating that they are consistent with the Ru 3p spectrum. Ru related peaks appear to be related to RuO 2 attached to the CC surface as well as Ru-CuO nanorods.…”

“…Ru related peaks appear to be related to RuO 2 attached to the CC surface as well as Ru-CuO nanorods. 33 To investigate the Ru doping relevance of Ru-CuO nanorods, it is considered appropriate to examine the O 1s spectrum. In O 1s spectrum of Ru-CuO/RuO 2 @CC (Figure 4D), the binding energy of 530.0 eV is correspond to lattice oxygen (O latt ), and the other peaks at 531.7 and 533.5 eV indicate oxygen vacancies (O vac ) and surface adsorbed water molecules (O ads ), respectively.…”