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Ba 2 InTaO 6 – A Partially B‐Site‐Ordered Double Perovskite for Overall Water Splitting
Author(s) -
Song Kai,
Yang Jia,
Jiang Pengfei,
Gao Wenliang,
Cong Rihong,
Yang Tao
Publication year - 2015
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201500929
Subject(s) - chemistry , water splitting , photocatalysis , rietveld refinement , oxygen evolution , perovskite (structure) , band gap , crystallography , non blocking i/o , reagent , catalysis , annealing (glass) , visible spectrum , octahedron , crystal structure , analytical chemistry (journal) , materials science , metallurgy , electrochemistry , biochemistry , optoelectronics , electrode , chromatography
Completely B‐site‐ordered Ba 2 InTaO 6 has been prepared previously by prolonged heating at 1500 °C; here, we significantly lowered the annealing temperature to 1130 °C under H 2 /Ar dynamic flow and obtained a partially ordered (ca. 74 %) double perovskite, as determined by Rietveld refinement of the powder X‐ray diffraction data. As a wide‐band‐gap semiconductor, Ba 2 InTaO 6 possesses photocatalytic activity for overall water splitting under UV irradiation, though the gas evolution rates of 12.9 and 6.6 μmol/h/g for H 2 and O 2 generation, respectively, are low. With the assistance of methanol as a sacrificial reagent, the H 2 evolution rate increases to 50.5 μmol/h/g, which indicates that the surficial charge recombination rate is really high. We applied the typical cocatalyst‐loading method to this material, and with 1 wt.‐% PtO x and NiO x , the H 2 production rates in pure water were further improved to 16.0 and 18.4 μmol/h/g, respectively. Attempts to dope Ba 2 InTaO 6 with first‐row transition metals (Ti, V, Cr, Mn, Fe, Co, and Ni) led to a general enhancement of the light‐harvesting ability; however, the experimental water‐splitting activity did not improve. We believe that the doped cations most likely behaved as recombination centers for photogenerated charges. Considering its structural similarity to the well‐known catalyst InTaO 4 :Ni, Ba 2 InTaO 6 possesses the potential to extend its photocatalytic activity to the visible‐light region but needs further enhancement.