On the formation of superoxide radicals on colloidal ATiO₃ (A = Sr and Ba) nanocrystal surfaces

Abstract

Superoxide defect formation on the surfaces of ATiO3 nanocrystals depends on the presence of lactate ions and oxygen during synthesis.

Tunable Redox Activity at Fe3+ Centers in Colloidal ATiO3 (A = Sr and Ba) Nanocrystals

“…Herein, we report the preparation of sub-10 nm Fe-doped SrTiO 3 and BaTiO 3 colloidal NCs using hydrothermal methods described previously by our group. 26,27 We confirm that Fe is in the Fe 3+ state and is located at the octahedral Ti 4+ of Fe 3+ disappears with increasing Ti 3+ concentration. The lack of Fe 3+ EPR signal in the photodoped SrTiO 3 and BaTiO 3 persists down to 100 K, where the Ti 3+ EPR signal is observed.…”

“…The discovery of this efficient and reversible control over the spin relaxation time of localized Cr 3+ inspired our current work to explore the behavior of additional aliovalent magnetic dopants in d 0 semiconductor NCs. Herein, we report the preparation of sub-10 nm Fe-doped SrTiO 3 and BaTiO 3 colloidal NCs using hydrothermal methods described previously by our group. , We confirm that Fe is in the Fe 3+ state and is located at the octahedral Ti 4+ sites in as-prepared NCs by electron paramagnetic resonance (EPR) spectroscopy. Upon anaerobic photodoping of colloidal NCs, the EPR signal of Fe 3+ disappears with increasing Ti 3+ concentration.…”

“…The synthesis of BaTiO 3 NCs was carried out by a similar hydrothermal method but included constant magnetic stirring . In a typical synthesis, 1.5 mmol of each of TALH and Ba­(OH) 2 was dissolved in 24 mL of distilled water followed by 6 mL of 5 M NaOH aqueous solution.…”

“…The synthesis of BaTiO 3 NCs was carried out by a similar hydrothermal method but included constant magnetic stirring. 27 In a typical synthesis, 1.5 mmol of each of TALH and Ba(OH) 2 was dissolved in 24 mL of distilled water followed by 6 mL of 5 M NaOH aqueous solution. The reaction mixture was then transferred to a 45 mL Teflon-lined autoclave, and oleylamine (6 mmol), oleic acid (6 mmol), and hydrazine (6 mmol) were added.…”

Surfactant-Free Synthesis of Three-Dimensional Perovskite Titania-Based Micron-Scale Motifs Used as Catalytic Supports for the Methanol Oxidation Reaction

“…Specifically, the synthetic route can determine not only size, shape, and morphology but also the achievable active surface area available to the perovskite catalysts [ 12 , 13 , 20 , 21 ]. A number of fabrication methods have been proposed over the years, to ensure chemical purity and structural integrity, including but not limited to hydrothermal and solvothermal syntheses [ 20 , 21 ], solid state reactions [ 22 , 23 ], sonochemical protocols [ 24 ], and arc-melting methods [ 25 ]. However, some of these procedures, especially those related to solid state reactions, sonochemistry, and arc-melting, tend to be limited by reproducibility, yield little if any morphological control, and/or are more prone to cost and technical limitations.…”