Screening tests for the evaluation of nanoparticle titania photocatalysts

Abstract

BACKGROUND: Nano-sized titanium dioxide has potential as a photocatalyst, and doped variants may have different photocatalytic properties. Nano-titanias with a wide range of dopants and compositions can be prepared using continuous hydrothermal flow synthesis (CHFS), but when many samples are made, a large-scale screening test is required to investigate their properties. A range of doped nano-titanias were prepared using a CHFS route, and investigated as powders using a range of photocatalytic test methods. These tests included decolourization of methylene blue (in the presence of oxygen), partial oxidation of a simple alcohol (propan-2-ol) and the degradation of aqueous solutions of dichloroacetic acid. The practicality of the tests for large-scale screening was considered, and the test results were cross-correlated to see if any of them gave similar ranking for activity of the photocatalysts.

Superhydrophobic Photocatalytic Surfaces through Direct Incorporation of Titania Nanoparticles into a Polymer Matrix by Aerosol Assisted Chemical Vapor Deposition

“…Oleic Acid Functionalization of Hydrothermally Synthesized Anatase Nanoparticles : Anatase NPs were synthesized hydrothermally under the following reaction conditions: pressure = 24.1 MPa, supercritical water temperature = 400 °C, flow rate = 400 mL min −1 . This was done using [TiOSO 4 ] (aq, 0.925 M ) and [KOH] (aq, 2 M ) precusors 21. The particles were then heated to 80 °C in excess oleic acid (120 mmol, 38.1 mL), with a catalytic amount of triethylamine (8 mmol, 1.12 mL) added to encourage ester formation between the titanol groups on the particle surfaces and the oleic acid.…”

“…The AACVD process utilizes chloroform solutions of thermosetting (Sylgard‐184) polydimethylsiloxane (PDMS) polymer in conjunction with functionalized titania nanoparticles (NPs). The titania NPs were synthesized using continuous hydrothermal flow synthesis (17 nm average diameter, bandgap = 3.17 eV) 21. This was followed by functionalisation with oleic acid, which rendered them soluble in organic solvents.…”

In situ variable temperature X-ray diffraction studies on the transformations of nano-precursors to La–Ni–O phases

“…The powders were prepared using a continuous hydrothermal flow synthesis (CHFS) system as described elsewhere [26][27][28][29][30][31][32][33][34][35][36]. The as-prepared powders were mixtures of La(OH) 3 and Ni(OH) 2 nanoparticles with La/Ni metal ion ratios of 1:1, 2:1, 3:2 and 4:3.…”

“…CHFS or similar reactors have been used to rapidly and efficiently produce numerous inorganic metal oxide nanoparticles from premixed metal salt solutions, which can rapidly be co-precipitated as homogeneously mixed oxides or solid solutions when mixed with a flow of supercritical water (which is typically at 4 400 1C and 422 MPa). Further details of this process are given elsewhere [26][27][28][29][30][31][32][33][34][35][36].…”

High-throughput continuous hydrothermal flow synthesis of Zn–Ce oxides: unprecedented solubility of Zn in the nanoparticle fluorite lattice

“…The new HiTCH reactor has also been developed by the authors into a fully automated robot called RAMSI (Rapid Automated Materials Synthesis Instrument), which automatically mixes the metal salt precursors, introduces them sequentially into the reactor via an Isco pump (includes auto-cleaning of the pump and reactor between each composition), and then makes, collects, cleans and prints many unique composition slurries in a few hours (Lin et al 2009;Thompson et al 2009). …”