Applied bias photon-to-current conversion efficiency of ZnO enhanced by hybridization with reduced graphene oxide

The role of reduced graphene oxide（rGO） in the enhancement of photo-conversion efficiency of ZnO films for photoelectrochemical（PEC） water-splitting applications was analyzed. ZnO and rGO-hybridized ZnO（rGO/ZnO） films were prepared via a two-step electrochemical deposition method followed by annealing at 300 °C under argon gas flow. The physical, optical and electrochemical properties of the films were characterized to identify the effect of rGO-hybridization on the applied bias photon-to-current efficiency（ABPE） of ZnO. Scanning electron microscopy and X-ray diffraction indicated the formation of verticallyaligned, wurtzite-phase ZnO nanorods. Diffuse-reflectance UV–visible spectroscopy indicated that rGO-hybridization was able to increase the light absorption range of the rGO/ZnO film. UPS analysis showed that hybridization with rGO increased the band gap of ZnO（3.56 eV） to 3.63 eV for rGO/ZnO sample,which may be attributed to the Burstein–Moss effect. Photoluminescence（PL） spectra disclosed that rGOhybridization suppressed electron-hole recombination due to crystal defects. Linear sweep voltammetry of the prepared thin films showed photocurrent density of 1.0 and 1.8 m A/cm;for ZnO and rGO/ZnO at+0.7 V, which corresponded to an ABPE of 0.55% and 0.95%, respectively. Thus, this report highlighted the multi-faceted role of rGO-hybridization in the enhancement of ZnO photo-conversion efficiency.

Effect of diluent and reaction parameter on selective oxidation of propane over MoVTeNb catalyst using nanoflow catalytic reactor

The selective oxidation of propane to acrylic acid over an MoVTeNb mixed oxide catalyst, dried and calcined before reaction has been studied using high-throughput instrumentation, which is called nanoflow catalytic reactor. The effects of catalyst dilution on the catalytic performance of the MoVTeNb mixed oxide catalyst in selective oxidation of propane to acrylic acid were also investigated. The effects of some reaction parameters, such as gas hourly space velocity （GHSV） and reaction temperature, for selective oxidation of propane to acrylic acid over diluted MoVTeNb catalyst have also been studied. The configuration of the nanoflow is shown to be suitable for screen catalytic performance, and its operating conditions were mimicked closely to conventional laboratory as well as to industrial conditions. The results obtained provided very good reproducibility and it showed that preparation methods as well as reaction parameters can play significant roles in catalytic performance of these catalysts.