Structural and thermal studies of H2La2/3Ta2O7, a protonated layered perovskite

Eu0.56Ta2O7: A New Nanosheet Phosphor with the High Intrananosheet Site Photoactivator Concentration

“…The first precursor Li 2 Eu 0.56 Ta 2 O 7 was synthesized by the solid-state reaction of Li 2 CO 3 , Eu 2 O 3 , and Ta 2 O 5 at 1600 °C, similar to that reported for its La analogue Li 2 La 2/ 3 Ta 2 O 7 , with some modifications . Li 2 Eu 0.56 Ta 2 O 7 was then ground and reacted with 2 M HNO 3 for 3 days at room temperature under vigorous shaking to exchange its Li + with H + . − This process was necessary in order to activate the bulk precursor for the following exfoliation reaction. The elemental compositions of the first and protonated precursors analyzed by EPMA are 0.56:2 Eu/Ta for both precursors, corroborating no reduction of the Eu content from the first precursor during the protonation reaction.…”

Synthesis and Characterization of K2Ln2/3Ta2O7·nH2O (Ln= La, Pr, Nd), Layered Tantalates Photocatalysts for Water Splitting.

“…In this synthetic route, an important element to consider refers to the calcination temperature because once this exceeds 900°C, undesired tungsten-bronze type compounds appear in the XRD patterns [25]. Several authors have referred to the appearance of tungsten bronzes, obtained by the solid-state reaction method [26]- [28].…”

Metastable Sr0.5TaO3 Perovskite Oxides Prepared by Nanosheet Processing

“…[42] The raw materials SrCO 3 , Ta 2 O 5 , and K 2 CO 3 (40 mol-% excess) were thoroughly mixed and calcined at 850°C for 6 h and sintered at 1200°C for 10 h. Ion exchange [43][44][45] (Figure 1a), which was used for synthesizing metastable Sr 0.5 TaO 3 with a threedimensional perovskite structure (Figure 1d). Sr 0.5 TaO 3 powder was prepared by two different processes: (1) direct dehydration of the host material [44,[46][47][48][49][50] and (2) nanosheet processing (Figure 1). In the direct dehydration process, the host material H 2 Sr 1.5 Ta 3 O 10 was dehydrated by heat treatment at 600°C for 2 h in air, which led to Sr 0.5 TaO 3 powder.…”