Effect of Ruthenium Modification of g-C3N4 in the Visible-Light-Driven Photocatalytic Reduction of Cr(VI)

Graphitic carbon nitride (g-C3N4) is a promising heterogeneous photocatalyst in the visible range. It can be used, among others, for reductive conversion of toxic hexavalent chromium occurring various wastewaters. Its photocatalytic efficiency, however, has to improved, which realized by modification with different dopants or co-catalysts forming heterojunctions. In our work, ruthenium-modified g-C3N4 been prepared ultrasonic impregnation pristine g-C3N4, was synthesized from thiourea. The morphology, microstructure, and optical properties photocatalysts were characterized XRD, SEM, FT-IR, TEM, XPS, DRS. Their compositions analyzed EDS XPS measurements, indicating 0.5% 1.4% Ru, due penetrating depths. study showed mainly +2 oxidation state Ru. DRS analysis indicated slight change both CB (from −1.14 −1.22 eV) VB 1.49 1.56 energies Ru/g-C3N4, compared those g-C3N4. Cr(VI) reduction efficacy increased 50.1 96.8%. Low pH (=2) preferred favorable surface charge E(Cr(VI)/Cr(III)) redox potential. Ru proved improving performance