Graphene-based strontium niobate-zinc oxide heterojunction photocatalyst for effective reduction of hexavalent chromium

A hydrothermal technique was employed to synthesize a Sr₂Nb₂O₇-rGO-ZnO (SNRZ) ternary nanocatalyst, in which ZnO and Sr₂Nb₂O₇ were deposited on reduced graphene oxide (rGO) sheets. The surface morphologies, optical properties, and chemical states, of the photocatalysts were characterized to understand their properties. The SNRZ ternary photocatalyst was superior over the reduction of Cr (VI) to harmless Cr (III) compared to the efficiencies obtained using bare, binary, and composite catalysts. The effects of various parameters, including the solution pH and weight ratio, on the photocatalytic reduction of Cr (VI) were investigated. The highest photocatalytic reduction performance (97.6%) was achieved at pH 4 and a reaction time of 70 min. Photoluminescence emission measurements were used to confirm efficient charge migration and separation across the SNRZ, which improved the reduction of Cr (VI). A feasible reduction mechanism for the SNRZ photocatalyst is proposed. This study presents an effective, inexpensive, non-toxic, and stable catalyst, for the reduction of Cr (VI) to Cr (III) using SNRZ ternary nanocatalysts.

Crystal structure and Hirshfeld surface analysis of (1H-imidazole-κN3)[N-(2-oxido-benzyl-idene)tyrosinato-κ3O,N,O']copper(II)

The title copper(II) complex, [Cu(C16H13NO4)(C3H4N2)], consists of a tridentate ligand synthesized from l-tyrosine and salicyl-aldehyde. One imidazole mol-ecule is additionally coordinating to the copper(II) ion. The crystal structure features N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds. The Hirshfeld surface analysis indicates that the most important contributions to the packing are from H⋯H (37.9%), C⋯H (28.2%) and O⋯H/H⋯O (21.2%) contacts.

Photofunctions in Hybrid Systems of Schiff Base Metal Complexes and Metal or Semiconductor (Nano)Materials

Composite materials very often provide new catalytic, optical or other physicochemical properties not observed for each component separately. Photofunctions in hybrid systems are an interesting topic of great importance for industry. This review presents the recent advances, trends and possible applications of photofunctions of hybrid systems composed of Schiff base metal complexes and metal or semiconductor (nano)materials. We focus on photocatalysis, sensitization in solar cells (DSSC-dye sensitized solar cell), ligand-induced chirality and applications in environmental protection for Cr(VI) to Cr(III) reduction, in cosmetology as sunscreens, in real-time visualization of cellular processes, in bio-labeling, and in light activated prodrug applications.

A series of POM compounds constructed using a flexible ligand containing three coordination groups: electrocatalytic and photocatalytic reduction and amperometric detection of Cr(vi)

Four polyoxometalate-based compounds can be used as electrocatalysts and electrochemical sensors for amperometric detection of NO2− and Cr(VI), and also have the performance of photocatalytic reduction of Cr(VI).