Palladium‐Modified TiO₂/MWCNTs for Efficient Carbon Capture and Photocatalytic Reduction of Nitro‐aromatic Derivatives

Abstract

In this study, modified TiO2 nanocomposites with the noble metal (Ag or Pd) followed by dispersion on multiwall carbon nanotubes (MWCNT) were synthesized and applied in the photocatalytic oxidation of CO at room temperature in the absence of oxygen. The results revealed that the highest active photocatalyst was Pd/TiO2/MWCNT towards CO and p‐nitrophenol (PNP) conversion. The reaction was dependent on the catalyst loading, concentration of tert‐butyl ammonium bromide (TBAB) as co‐catalyst and the reaction time as well as the temperature of their reduction. It was found that the optimal condition for PNP transformed into p‐aminophenol (PAP) and formic acid (HCOOH) was the use of 0.05 wt % of Pd/TiO2/MWCNT nanocatalyst, 2 mol % of TBAB under visible light irradiation condition at room temperature after 1 hour. The as‐prepared photocatalysts were fully characterized using Scanning electron microscope (SEM‐EDX), high resolution transmission electron microscope (HR‐TEM), X‐ray diffraction (XRD) and Brunauer‐Emmett‐Teller (BET). In addition, the band gaps of TiO2 nanoparticles, TiO2/MWCNT and Ag‐ or Pd‐modified TiO2/MWCNT nanocomposites were calculated from diffuse reflectance spectroscopic (DRS) analysis, ensuring the best photocatalytic efficiency. This approach is significantly beneficial for development of new generation of detoxification/transformation catalysts. The probable mechanism of photo‐oxidation of CO by H2O was postulated.

Sodium Alginate–CdS Nanostructures: Reinforcing Chemoselectivity in Nitro-Organic Reduction and Dye Degradation through Photoinduced Electron Transfer

“…In this control experiment, the peak at 380 nm remains unchanged, illustrating that the catalyst is inactive in dark conditions. Figure b, on the other hand, depicts the same curve with the incorporation of blue light, where the peak intensity of 4-NA at 380 nm decreased, but the peaks associated with the reaction product 4-AA at 300 nm increased concurrently . For SA–CdS@pH 13, the reaction could be finished in 14 min; however, SA–CdS@pH 10 and SA–CdS@pH 7 required slightly more time as depicted in Figure S11.…”

“…Figure 5b, on the other hand, depicts the same curve with the incorporation of blue light, where the peak intensity of 4-NA at 380 nm decreased, but the peaks associated with the reaction product 4-AA at 300 nm increased concurrently. 55 For SA−CdS@pH 13, the reaction could be finished in 14 min; however, SA−CdS@pH 10 and SA−CdS@ pH 7 required slightly more time as depicted in Figure S11. This study demonstrates the photocatalytic activity of SA−CdS for 4-NA reduction.…”