Results in Physics (Jun 2019)
Role of organic/inorganic-sulfur doping on photocatalytic behavior of mesoporous bimetallic oxides heterojunction
Abstract
A series of novel sulfur-doped mesoporous bimetallic oxides with controllable structure and property were synthesized for acid-induced photo-Fenton. The one-pot sol-gel strategy allowed high-dispersion and strong adhesion of different organic-/inorganic-sulfur species (including CH4N2S, C5H11NO2S, (NH4)2SO4 and Na2S2O3) in host matrix to achieve highly active bimetallic heterojunction with stronger acid strength. It was found that organic-sulfur doping tended to simultaneously produce Brønsted and Lewis acid while inorganic-sulfur doping only generated Lewis acid. When two kinds of acid sites appeared on surface of solid, it made significant contributions toward superior performance either in absence of light (90.7% decoloration) or at pH of 10.0 (97.7% decoloration and 60.9% TOC removal). Possible sulfuration mechanism of S-doped bimetallic oxides for H2O2 activation had been explored in details. The acidity of solids was inversely related to chain length of organic-sulfur but positively correlated with electronegativity of inorganic-sulfur. The study will not only make a facile and effective way for developing highly-efficient heterogeneous catalysts, but also provide valuable insights for understanding relationship between surface physicochemical properties and catalytic activity. Keywords: Mesoporous bimetallic oxide, Sulfur-doping, Photo-Fenton, Brønsted and Lewis acid sites, Sulfuration mechanism