Effects of Cocatalyst and Calcination Temperature on Photocatalytic Hydrogen Evolution Over BaTi4O9 Powder Synthesized by the Polymerized Complex Method

Abstract

BaTi 4 O 9 powders with improved crystal perfection and relatively large surface area were synthesized by the polymerized complex (PC) method calcined at reduced temperatures (700-1,000°C) relative to the solidstate reaction (SSR) method. BaTi 4 O 9 with a unique pentagonal-prism tunnel structure, combined with different cocatalysts (Pt, Ru, Ni, Cu, Co) as promoters, was investigated towards photocatalytic reactions for H 2 evolution from pure water and aqueous ethanol solution. Pt/BaTi 4 O 9 achieved the highest activity from ethanol solution, and subsequently it was focused to study the effect of calcination temperature on photocatalytic activities. The maximum quantum yield for H 2 evolution from pure water and ethanol solution was obtained at 700 and 800°C separately, with the value of 0.9% and 11.7% over Pt/BaTi 4 O 9 photocatalysts.

Synthesis of Nanocrystalline of Lanthanum Doped NaTaO3 and Photocatalytic Activity for Hydrogen Production

“…To resolve this issue and enhance the photocatalytic activity of the photocatalyst, various approaches have been employed, including doping the semiconductors with other impurities [16] and optimization of reaction conditions by setting the calcination temperature [17] in order to improve the crystallinity of the material. However, the effects of the calcination temperature on the morphology and photocatalytic activity of La-NaTaO 3 have not yet been reported.…”

Synthesis and photocatalytic property of BaTi4O9/RuO2 nanocomposites

“…In recent years, a variety of metal oxides with tunnel structure have been found to be active for H 2 production under ultraviolet-light illumination [2][3][4]. Among these oxides, the compound BaTi 4 O 9 with a pentagonal prism tunnel structure has received considerable attention as a new host catalytic material in combination with RuO 2 for stoichiometrically complete photodecomposition of water [5][6][7]. Inoue et al have suggested that the tunnel structure of the BaTi 4 O 9 material has an important effect on the excellent photocatalytic activities since it brings about a significantly large distortion of TiO 6 octahedra, which possibly leads to efficient production of photo-excited charges and prevents RuO 2 particles from aggregating and growing into large particles [3].…”

Solar Fuels by Heterogeneous Photocatalysis: From Understanding Chemical Bases to Process Development

“…As pointed out by Ma et al [156], a lot of papers make claims about "water splitting" while using a so-called hole scavenger [157]; but since no oxygen is evolved in this case, it is more proper to term these reactions as photoreforming or partial water splitting [156]. Despite its attractiveness, this reaction is more difficult than PR, both from a thermodynamic and kinetic point of view, leading to lower hydrogen productivity [158].…”

“…Moreover, few comparisons among these non-noble metal co-catalysts exist. Fujita et al reported an increased reactivity, in order, CoO x < NiO < CuO on TiO 2 [226], while Sun et al observed an improved hydrogen evolution, in order, RuO x < NiO < CuO < CoO x < Pt on a barium titanate [158], suggesting that interactions between the co-catalyst and the main semiconductor play a crucial role too. Alloying has been proved to boost the catalytic activity [227][228][229], probably due to synergistic effects among the two components as suggested by Jung et al [230]; unfortunately, these reported alloys contain at least one noble metal, increasing the cost of the catalyst.…”