Preparation of sulfur doping carbon nitride microsphere and its photocatalytic reduction properties.

Sulfur doped carbon nitride materials (CNS) were prepared from solvothermal method at low temperature, using thiocyanuric acid as one of the precursors. XRD, FTIR, SEM and XPS technologies were carried out to characterize the catalysts. The photocatalytic reduction properties of CNS were tested by Cr(VI) reduction and H2 production from water splitting. Results showed that sulfur substituted crystal nitrogen in the carbon nitride molecular and formed C--S bonds. With the increasing time of polymerization, the content of sulfur in the products increased. The catalysts showed remarkable visible light absorbance, and the optical absorption band edges red shifted up to about 700 nm with the increasing time of polymerization. Compared to the carbon nitride synthesized from direct calcination, CNS possessed much enhanced photocatalytic reduction activity of Cr(VI) under visible light irradiation. In addition, CNS catalysts had obvious H2 production properties from water splitting. Mechanism analysis showed that photo-generated electrons and ⋅ O2v- were major active species during photocatalytic reduction of Cr(Vi) over CNS catalysts. [ABSTRACT FROM AUTHOR]