Double-Nozzle Flame Spray Pyrolysis as a Potent Technology to Engineer Noble Metal-TiO2 Nanophotocatalysts for Efficient H2 Production

Abstract

Noble metal-TiO2 nanohybrids, NM0-TiO2, (NM0 = Pt0, Pd0, Au0, Ag0) have been engineered by One-Nozzle Flame Spray Pyrolysis (ON-FSP) and Double-Nozzle Flame Spray Pyrolysis (DN-FSP), by controlling the method of noble metal deposition to the TiO2 matrix. A comparative screening of the two FSP methods was realized, using the NM0-TiO2 photocatalysts for H2 production from H2O/methanol. The results show that the DN-FSP process allows engineering of more efficient NM0-TiO2 nanophotocatalysts. This is attributed to the better surface-dispersion and narrower size-distribution of the noble metal onto the TiO2 matrix. In addition, DN-FSP process promoted the formation of intraband states in NM0-TiO2, lowering the band-gap of the nanophotocatalysts. Thus, the present study demonstrates that DN-FSP process is a highly efficient technology for fine engineering of photocatalysts, which adds up to the inherent scalability of Flame Spray Pyrolysis towards industrial-scale production of nanophotocatalysts.

In Tandem Control of La-Doping and CuO-Heterojunction on SrTiO3 Perovskite by Double-Nozzle Flame Spray Pyrolysis: Selective H2 vs. CH4 Photocatalytic Production from H2O/CH3OH

“…Herein, we employ a Single-Nozzle FSP (SN-FSP) process for the synthesis of La:SrTiO 3 and a Double-Nozzle FSP (DN-FSP) creating a heterojunction of CuO finely dispersed on La:SrTiO 3 in one-step [ 46 , 47 ], see Figure 1 . Recently, our group utilized DN-FSP to produce TiO 2 loaded with noble metal particles (>2 nm), to significantly enhance photocatalytic hydrogen production [ 48 ]. In the present work, our hypothesis was that an in tandem La-doping of SrTiO 3 heterojunctions with CuO can allow control of the SrTiO 3 electronic/photocatalytic properties, as well as controlled selectivity in photocatalytic products.…”

Multipotent Atomic Palladium Species Pd1+, Pd2+–O2–, and Pd3+ Formed at the Interface of Pd/TiO2 Nanoparticles: Electron Paramagnetic Resonance Study

“…Our lab-scale FSP reactor used for the synthesis of Pd/TiO 2 nanoparticles has been described previously. − Herein, three different FSP protocols were implemented for the synthesis of Pd/TiO 2 : by varying the oxidation atmosphere in the combustion process, we have prepared three families of materials, that is, encoded “O 2 -Rich”, “Ambient O 2 ”, and “O 2 -Lean”, see details hereafter.…”

Flame Spray Pyrolysis Engineering of Nanosized Mullite-Bi2Fe4O9 and Perovskite-BiFeO3 as Highly Efficient Photocatalysts for O2 Production from H2O Splitting

“…Experiments with Pt 0 , Au 0 , or Ag 0 were realized using hydrogen hexachloroplatinate (IV) hydrate, (H 2 Pt 4 Cl 6 •H 2 O, 99.9 %, Alfa Aesar), hydrogen tetrachloro-aurate (III) trihydrate (HAuCl 4 •3H 2 O, 99.9 %, Alfa Aesar), and Silver nitrate (I) (AgNO 3 , 99.9 %, Sigma Aldrich). In all experiments, the cocatalytic noble-metal particles were photo deposited in-situ: after the addition of all compounds in the reactor, an irradiation period of 15 min was necessary to achieve the in-situ reduction of the Pt, Au, or Ag cations [28].…”