Polyamine-Mediated Interfacial Assembly of rGO-ZnO Nanostructures: A Bio-inspired Approach and Enhanced Photocatalytic Properties

Abstract

A bio-inspired approach for the fabrication of reduced graphene oxide (rGO) embedded ZnO nanostructure has been attempted to address issues pertaining to charge recombination and photocorrosion in ZnO for application as an effective photocatalyst. Herein we demonstrate the synthesis of rGO-ZnO nanostructures in a single step using polyamines, which simultaneously aid in the mineralization of ZnO nanostructures from zinc nitrate, reduction of graphene oxide (GO), and finally their assembly to form rGO-ZnO composite structures under environmentally benign conditions. The interspersed nanocomponents in the assembled heterostructures result in enhanced photocatalytic activity under UV light, indicating an effective charge separation of the excited electrons. Furthermore, the composite structure provides stability against photocorrosion for efficient recyclability of the catalyst.

TiO2@Carbon Photocatalysts: The Effect of Carbon Thickness on Catalysis

“…When the thickness of the carbon shell is greater than 2 nm, the reaction rate is even slower than for pure TiO 2 . The catalytic efficiency of the photocatalysts was verified again for the photodegradation of other organic compounds of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 rhodamine B (RhB), 52 as TiO 2 @C with ~4 and ~8 nm carbon layers have the highest BET surface area, and therefore the largest capacity to adsorb reactants, but the lowest activity for photodegradation.…”

“…It has been reported that 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 photogenerated holes can react with the surface oxygen atoms of an inorganic oxide photocatalyst, leading to an activity decrease. 52,56 At the oxide-carbon interface, interfacial C-O bonds can prevent the activation of the surface oxygen atoms by the holes, therefore leading to an improved photostability. 52,56 Accordingly, the good catalytic stability for the TiO 2 @C sample is likely to be attributed to the strong interfacial interaction between TiO 2 and C layer as implied in its Raman spectra (Figure 2-d).…”

“…(c) Photocatalytic degradation of several organic compounds (rhodamine B: RhB, methylene blue: MB and 4-chlorophenol: 4-CP) under UV-light. (d) Repeated runs for the decomposition of MO using TiO 2 @C-2 catalyst under UV light.The effect of the carbon shell thickness on photocatalytic activity of TiO 2 @C samples was assessed through a methylene orange (MO) photodegradation experiment -an experiment which has been widely used for the assessment of the catalytic activity of TiO 2 photocatalysts 39,52. The concentration of MO is quantified by separating the TiO 2 @C particles and by monitoring the…”

“…, the MO solution is contacted with the catalyst under darkness until an adsorption-desorption equilibrium is attained 39,52. This process (gray area,Figure 4-a) reached equilibrium in ~20 min (t = -40 min).…”

The highly enhanced visible light photocatalytic degradation of gaseous o -dichlorobenzene through fabricating like-flowers BiPO 4 /BiOBr p-n heterojunction composites

“…The PL spectroscopy is usually used to investigate the seperation of the photo-induced electron-hole pairs in semiconductor photocatalysts [53,54]. Generally, the weaker is a PL spectra signal, the higher is separation efficiency of photo-induced electron-hole pairs.…”