High specific surface CeO2-NPs doped loose porous C3N4 for enhanced photocatalytic oxidation ability

Porous C3N4 (PCN) is favored by researchers because it has more surface active sites, higher specific surface area and stronger light absorption ability than traditional g-C3N4. In this study, cerium dioxide nanoparticles (CeO2-NPs) with mixed valence state of Ce3+ and Ce4+ were doped into the PCN framework by a two-step method. The results indicate that CeO2-NPs are highly dispersed in the PCN framework, which leads to a narrower band gap, a wider range of the light response and an improved the separation efficiency of photogenerated charge in PCN. Moreover, the specific surface area (145.69 m2•g-1) of CeO2-NPs doped PCN is a 25.5 % enhancement than that of PCN (116.13 m2•g-1). In the experiment of photocatalytic selective oxidation of benzyl alcohol, CeO2-NPs doped porous C3N4 exhibits excellent photocatalytic activity, especially Ce-PCN-30. The conversion rate of benzyl alcohol reaches 74.9 % using Ce-PCN-30 as photocatalyst by 8 hours of illumination, which is 25.7 % higher than that of pure porous C3N4. Additionally, CeO2-NPs doped porous C3N4 also exhibits better photocatalytic efficiency for other aromatic alcohols.

Ti(IV)-exchanged nano-ZIF-8 and nano-ZIF-67 for Enhanced Photocatalytic Oxidation of Hydroquinone

The metal centres of nano-ZIF-8(Zn) and nano-ZIF-67(Co) were partially exchanged with titanium centres to form bimetallic nZIF-8(Zn/Ti) (52% Ti4+) and nZIF-67(Co/Ti) (38% Ti4+) respectively, for enhanced photocatalytic performance. A morphological and structural analysis by SEM, EDS-Mapping and PXRD showed that the particle size, distribution, and the structural integrity of the Sodalite frameworks of the parent ZIFs were retained during the exchange process to form the new bimetallic Ti-ZIFs. FTIR confirmed that no additional chemical bonds were formed during the process. XPS binding energies confirmed the preservation of the Zn(II), Co(II) and Ti(IV) oxidation states, as well as the Ti-content, consistent with ICP-OES and EDS measurements. The Ti-exchanged ZIFs showed higher activity during the photocatalytic oxidation of hydroquinone in comparison with their parent ZIFs. Their kinetic rates were nearly five times faster than those of the parent ZIFs, with the first-order rate constants k = 0.189 min-1 for nZIF-8(Zn/Ti) and k = 0.139 min-1 for nZIF-67(Co/Ti). These catalysts are efficient, stable, and reusable for three photocatalytic cycles without a significant loss of catalytic activity.

Selective and efficient catalytic and photocatalytic oxidation of diphenyl sulphide to sulfoxide and sulfone: the role of hydrogen peroxide and TiO2 polymorph

Selective sulfoxide and sulfone production can be precisely controlled by choosing TiO2 polymorph and the reaction mode (catalysis versus photocatalysis).

A critical review on surface modified nano-catalysts application for photocatalytic degradation of volatile organic compounds

Surface modification of nano-catalyst got significant attention due its outstanding photocatalytic performance with minimum secondary pollution. Photocatalytic oxidation (PCO) is a promising technology for removing volatile organic compounds (VOCs) due...

Solvent controlled selective photocatalytic oxidation of benzyl alcohol over Ni@C/TiO2

The oxidation of aromatic alcohols to produce carbonyl compounds is of great significance in fine chemical production. The traditional oxidation produces waste gas and pollutes the environment during the reaction. As a new field, photocatalysis has attracted people's attention because of its environmental friendliness. At present, there have been much research on TiO2, or noble metal modified TiO2 to catalyze alcohol oxidation, but the high cost is not conducive to large-scale production. Herein, a Ni@C/TiO2 catalyst was prepared by in-situ hydrothermal synthesis. This catalyst has a better oxidation effect on benzyl alcohol than Ni@C supported on TiO2 on the market and has a good catalytic effect on aromatic alcohols with different substituents. It is more interesting that the selectivity of the product can be adjusted by choosing different reaction solvents. The highly active catalyst with low cost and wide applicability has certain significance for the large-scale use of photocatalytic alcohol oxidation.