Robust charge carrier engineering via plasmonic effect and conjugated Π-framework on Au loaded ZnCr-LDH/RGO photocatalyst towards H2 and H2O2 production

Au loaded ZnCr-LDH/RGO ternary photocatalyst for H2 and H2O2 production under visible light illumination.

High-Performance 3D Semiconductor-Based Heterostructure Photocatalyst in Sustained Control of Harmful Gas-Phase Pollutants Under Visible-Light Illumination

Herein, a highly efficient three-dimensional (3D) semiconductor-based heterostructure photocatalyst (i.e., WO3–g-C3N4 monolithic architecture; WOCNM) was developed by immobilizing a WO3–g-C3N4 heterostructure powder on a melamine foam (MF) framework. Subsequently, the sustained control of two harmful model gas-phase pollutants (i.e., n-butanol and o-xylene) over WOCNM and selected monolithic counterparts (i.e., MF-supported WO3 monolith and MF-supported g-C3N4 monolith) was investigated under visible-light irradiation. WOCNM exhibited higher photocatalytic capabilities in the sustained control of the two model pollutants than those of individual WO3 and g-C3N4 monoliths because the WO3–g-C3N4 heterojunction enhanced its charge-separation ability. Notably, WOCNM exhibited highly efficient photocatalytic capabilities in the sustained control of n-butanol (up to 97%) and o-xylene (up to 86%). Moreover, no noticeable changes were observed in the WOCNM photocatalytic capability after the final run of successive applications. The fresh and successively used WOCNMs were nearly identical, and the photocatalyst powder was not observed in the reaction chamber after its successive application. As a result, WOCNM was a highly efficient and stable 3D heterostructure photocatalyst for the sustained control of gas-phase n-butanol and o-xylene, without significant catalyst powder loss. Promisingly, this study will expedite the future development of 3D photocatalysts for the sustained control of harmful gas-phase pollutants.

TiO2-rGO Composite for Photocatalytic Decolorization of Methylene Blue Under the Visible Light Illumination

Titanium dioxide-reduced graphene oxide (TiO2-rGO) was synthesized by hydrothermal method using TiO2 powder and rGO precursor from graphite rod by modified Marcano Method. The obtained TiO2-rGO photocatalyst was characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and Diffuse reflectance UV (DRUV). Based on XRD diffractogram, it is known that TiO2 has an anatase crystal phase. In the FTIR spectrum, it was observed that there was an absorption peak at the wavenumber of 1630 cm-1 from the vibration (C=C) as an indication that the C atom was incorporated into the TiO2 structure. The incorporation of C atoms into the TiO2 structure to form TiO2-rGO causes the bandgap energy to decrease from 3.29 eV to 3.20 eV. The photocatalytic activity was tested against decolorization of methylene blue solution for 180 minutes under visible light illumination from a 50 watt LED lamp. Every 10 minutes, absorbance was measured using a UV-Vis spectrophotometer at a wavelength of 664 nm. TiO2-rGO photocatalyst has better photocatalytic activity with %D of 96.39% under UV light and 84.32% under visible light illumination, while TiO2 is only able to degrade 93.87% and 36.55%, respectively.

Enhancing the photocatalytic activity of Ag-TiO2/SiO2 and its potential application in water treatment

Ag-doped TiO2/SiO2 with visible light response was prepared by a simple sol-gel method using titanium w-butoxide (TNB), tetraethoxysilane (TEOS) as precursors, and silver nitrate (AgNO3). The synthesized Ag-TiO2/SiO2 were characterized by SEM, XRD, PL (photoluminescence) emission and UV-Vis absorption spectroscopy. Their photocatalytic activities were evaluated by treating aqueous solutions of phenol under simulated visible light illumination. The role of silver doped was investigated in the range 1% – 5% (molar ratio), resulting in the best bandgap value of 2.93 eV for Ag(3%)-TiO2/SiO2 compared to 3,18 eV for the un-doped TiO2/SiO2. Consequently, the best phenol treating yield – about 97% after 4 hours – was obtained using Ag(3%)-TiO2/SiO2. So the synthesized Ag(3%)-TiO2/SiO2 might serve as a potential photocatalyst for water treatment using visible lights.