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

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.