Oxyhydrides of (Ca,Sr,Ba)TiO3 perovskite solid solutions

Area of Science:

• Solid-state chemistry
• Materials science
• Perovskite oxides

Background:

• Perovskite oxides (ABO3) are versatile materials with tunable properties.
• Oxyhydride perovskites offer unique chemical and physical characteristics due to hydrogen incorporation.
• Previous studies explored hydride incorporation in BaTiO(3-x)H(x).

Purpose of the Study:

• To synthesize and characterize novel oxyhydride solid solutions based on (Ca,Sr)TiO(3-x)H(x) and (Sr,Ba)TiO(3-x)H(x).
• To investigate the structural and chemical changes upon hydride incorporation.
• To understand the relationship between A-site composition and hydrogen release properties.

Main Methods:

• Synthesis of oxyhydride solid solutions via reduction of parent oxides with calcium hydride.
• Characterization of hydride content (x = 0.1-0.3).
• Analysis of changes in cell volume, octahedral tilt angle, and anion site occupancy.
• Measurement of hydrogen release temperature.

Main Results:

• Successful preparation of (Ca,Sr)TiO(3-x)H(x) and (Sr,Ba)TiO(3-x)H(x) with hydride content up to x=0.3.
• Larger particle size (20-30 μm) led to lower hydride content compared to nano-sized materials.
• Oxyhydrides exhibit structural characteristics consistent with regular ABO(3) perovskites.
• Hydrogen release temperature did not show a linear correlation with A-site composition, suggesting chemical randomness.

Conclusions:

• The synthesized oxyhydride perovskites maintain the characteristic ABO(3) perovskite structure.
• Particle size significantly impacts hydride incorporation efficiency.
• The non-linear scaling of hydrogen release temperature indicates complex interactions influenced by chemical disorder in the A-site.