Enhanced photocatalytic hydrogen generation from barium tantalate composites

Abstract

(111)-layered Ba5Ta4O15 photocatalysts were synthesised by a solid state reaction route and a citrate synthesis route, and their structural and electronic properties were investigated. After citrate route preparation, the presence of a second phase, namely Ba3Ta5O15, was determined by X-ray powder diffraction and absorption spectroscopy. The existence of this phase had a profound effect on the photocatalytic activity of this Ba5Ta4O15/Ba3Ta5O15 composite in comparison to the pure Ba5Ta4O15 materials. The photocatalytic performance of the barium tantalates was evaluated by investigating the capability in ˙OH radical formation and hydrogen generation. Strongly increased hydrogen evolution rates for the Ba5Ta4O15/Ba3Ta5O15 composite, up to 160% higher than for the pure Ba5Ta4O15, were determined, and only very small amounts of Rh co-catalyst, deposited on the photocatalysts by stepwise reductive photo-deposition, were needed to achieve these results.

Low-temperature route to metal titanate perovskite nanoparticles for photocatalytic applications

“…The reason is possibly related to the effect of the obtained by-phase anatase, forming nanocomposites with the SrTiO 3 , which can reduce the recombination of charge carriers at the surface of ionothermal prepared sample. We have roughly calculated band positions of SrTiO 3 and TiO 2 according to a simple procedure proposed by Butler and Ginley [10,42], where the estimated band gaps from UV-Vis spectroscopy of the samples, the electronegativities and the ionization energies of the respective elements are used. A possible mechanism for charge transfer is shown in Fig.…”

“…Plotting (αhν) 1/2 versus hν based on the spectral response gives the extrapolated corresponding E g values [10,24]. As shown in Figure SI (Table 1).…”

“…The co-catalyst Rh (0.5 wt%) was deposited onto the photocatalyst via reductive photodeposition from Na 3 RhCl 6 solution [10]. The N-doped sample was measured with the continuous gas flow of 25 NmL/min using the double-walled inner irradiation-type quartz reactor filled with a 2M NaNO 2 -solution to cut-off the UV light.…”

Synthesis of Phase Pure Hexagonal YFeO3 Perovskite as Efficient Visible Light Active Photocatalyst

“…In Figure 3b the Tauc plots obtained from the absorption data by plotting of (F(R)*hν) 1/2 versus the photon energy (hν) are shown, where F(R) is the Kubelka-Munk function. The band gap energies E gap obtained from the intercepts with the energy axis [28] show a difference of about 0.3 eV for the hexagonal and the orthorhombic YFeO 3 phase. With respect to the band gap of Fe 2 O 3 of 2.1 eV, the introduction of yttrium ions leading to the hexagonal perovskite phase causes a shift of the band gap to a lower energy.…”

Fabrication of hexagonal/cubic tungsten oxide homojunction with improved photocatalytic activity

“…Recently, the homojunction constituted by the different phases of the same photocatalyst has attracted much attention for it is simple, controllable and usually of great photocatalytic activity [10][11][12]. Li and coworkers reported that an efficient homojunction formed between the anatase and rutile TiO 2 nanoparticles could greatly enhance the photocatalytic activity for hydrogen production, suggesting that the enhanced photocatalytic activity was related to the efficient surface-phase junctions [13].…”