Involvement of water and visible light in the enhancement in SO2 adsorption at ambient conditions on the surface of zinc (hydr)oxide/graphite oxide composites

作者：Seredych Mykola; Mabayoje Oluwaniyi; Bandosz Teresa J^*

来源：Chemical Engineering Journal, 2013, 223: 442-453.

DOI：10.1016/j.cej.2013.03.026

• Graphite oxide
• Photoactivity
• Visible light
• Zinc (hydr)oxide
• Composites
• SO2 adsorption
• Water splitting

Composites of zinc (hydr)oxide-graphite oxide and of zinc (hydr)oxide-graphene were used as adsorbents of sulfur dioxide at ambient conditions. The initial and exhausted samples were characterized by XRD, FTIR, potentiometric titration, EDX, thermal analysis and adsorption of nitrogen. Cyclic voltammetry in light and dark was also used to show the photoactivity of the samples. The results obtained suggest that visible-light-enhanced water splitting reaction takes place on the surface of zinc (hydr)oxide and its composite with graphite oxide. This results in a significant improvement of these materials' performance as SO2 adsorbents at ambient conditions. Owing to the presence of electrons-hole pairs and their spatial separation by a conductive graphene based phase, at one location SO2 accepts the electrons and sulfide and sulfur are formed, whereas at the separate locations, where holes exist, SO2 acts as electron donor and sulfates are deposited on the surface with the release of hydrogen. Sulfur dioxide feeding to the system and running the experiments in the visible light provide the continuity to this process. The exhaustion of materials' reactive adsorption capability happens when sulfur species are deposited on all active sites, and therefore the active centers for water splitting and electron transfer are blocked and/or lose their photoactive properties.

• 出版日期2013-5-1