Ni-doped A-site excess SrTiO3 thin films modified with Au nanoparticles by a thermodynamically-driven restructuring for plasmonic activity

Both, Kevin Gregor; Reinertsen, Vilde Mari; Aarholt, Thomas; Jensen, Ingvild Julie Thue; Neagu, Dragoş; Prytz, Øystein; Norby, Truls; Chatzitakis, Athanasios

doi:10.1016/j.cattod.2022.11.011

Cited by 3 publications

(1 citation statement)

References 30 publications

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“…However, the previously reported exsolution systems fabricated by solution processes follow "crystal exsolution," which takes place under the condition opposite to amorphous exsolution (see the red dotted curve in Figure 5j), and this mechanism follows the black landscape in Figure 5j. [71][72][73][74][75][76][77][78] Clearly, when the dopant fails to exsolve from the amorphous oxide, it should overcome a significantly higher energy barrier to form a vacancy in a crystal (see the two-way arrow in Figure 5j), allowing only a limited amount of dopants to exsolve on the oxide surface (Figure S22, Supporting Information).…”

Section: Illustration Of Amorphous Exsolution In Co and Fe-doped Systemsmentioning

confidence: 99%

Maximizing Photoelectrochemical Performance in Metal‐Oxide Hybrid Composites via Amorphous Exsolution—A New Exsolution Mechanism for Heterogeneous Catalysis

Kim,

Hassan,

Lee

et al. 2023

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Exsolution generates metal nanoparticles anchored within crystalline oxide supports, ensuring efficient exposure, uniform dispersion, and strong nanoparticle–perovskite interactions. Increased doping level in the perovskite is essential for further enhancing performance in renewable energy applications; however, this is constrained by limited surface exsolution, structural instability, and sluggish charge transfer. Here, hybrid composites are fabricated by vacuum‐annealing a solution containing SrTiO3 photoanode and Co cocatalyst precursors for photoelectrochemical water‐splitting. In situ transmission electron microscopy identifies uniform, high‐density Co particles exsolving from amorphous SrTiO3 films, followed by film‐crystallization at elevated temperatures. This unique process extracts entire Co dopants with complete structural stability, even at Co doping levels exceeding 30%, and upon air exposure, the Co particles embedded in the film oxidize to CoO, forming a Schottky junction at the interface. These conditions maximize photoelectrochemical activity and stability, surpassing those achieved by Co post‐deposition and Co exsolution from crystalline oxides. Theoretical calculations demonstrate in the amorphous state, dopant─O bonds become weaker while Ti─O bonds remain strong, promoting selective exsolution. As expected from the calculations, nearly all of the 30% Fe dopants exsolve from SrTiO3 in an H2 environment, despite the strong Fe─O bond's low exsolution tendency. These analyses unravel the mechanisms driving the amorphous exsolution.

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Section: Illustration Of Amorphous Exsolution In Co and Fe-doped Systemsmentioning

confidence: 99%

Maximizing Photoelectrochemical Performance in Metal‐Oxide Hybrid Composites via Amorphous Exsolution—A New Exsolution Mechanism for Heterogeneous Catalysis

Kim,

Hassan,

Lee

et al. 2023

Small

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Amorphous Exsolution of Fe₃O₄ Nanoparticles in SrTiO₃: A Path to High Activity and Stability in Photoelectrochemical Water‐Splitting

Kim,

Lee,

et al. 2024

Small Structures

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Exsolution creates metal nanoparticles embedded within perovskite oxide matrices, promoting optimal exposure, even distribution, and robust interactions with the perovskite structure. Fe3O4, an oxidized form of Fe, is an attractive catalyst for photoelectrochemical (PEC) water‐splitting due to its strong light absorption, excellent electrical conductivity, and chemical stability. However, exsolving Fe is challenging, often requiring harsh reduction conditions that can decompose the perovskite. Herein, hybrid composites are fabricated for PEC water‐splitting by reductively annealing a solution of SrTiO3 photoanode and Fe cocatalyst precursors. In situ transmission electron microscopy reveals uniform, high‐density Fe particles exsolving from amorphous SrTiO3 films, followed by film‐crystallization at elevated temperatures. This innovative process extracts entire Fe dopants while maintaining structural stability, even at doping levels exceeding 50%. Upon air exposure, the embedded Fe particles oxidize to Fe3O4, forming a Schottky junction and enhancing light absorption. These conditions yield a high activity of 5.10 mA cm−2 at 1.23 V versus reversible hydrogen electrode (an 11.86‐fold improvement over SrTiO3) from the 30% Fe‐doped SrTiO3, with excellent stability (97% retention) over 24 h. Theoretical calculations indicate that in the amorphous state, FeO bonds weaken while TiO bonds remain strong, promoting selective exsolution. The mechanisms driving amorphous exsolution versus crystal exsolution are elucidated.

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Exsolution of Ni nanoparticles in A-site excess STO films

Both,

Neagu,

Prytz

et al. 2024

Nanoscale Adv.

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Ni-doped A-site excess SrTiO3 thin films modified with Au nanoparticles by a thermodynamically-driven restructuring for plasmonic activity

Cited by 3 publications

References 30 publications

Maximizing Photoelectrochemical Performance in Metal‐Oxide Hybrid Composites via Amorphous Exsolution—A New Exsolution Mechanism for Heterogeneous Catalysis

Maximizing Photoelectrochemical Performance in Metal‐Oxide Hybrid Composites via Amorphous Exsolution—A New Exsolution Mechanism for Heterogeneous Catalysis

Amorphous Exsolution of Fe₃O₄ Nanoparticles in SrTiO₃: A Path to High Activity and Stability in Photoelectrochemical Water‐Splitting

Exsolution of Ni nanoparticles in A-site excess STO films

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Ni-doped A-site excess SrTiO3 thin films modified with Au nanoparticles by a thermodynamically-driven restructuring for plasmonic activity

Cited by 3 publications

References 30 publications

Maximizing Photoelectrochemical Performance in Metal‐Oxide Hybrid Composites via Amorphous Exsolution—A New Exsolution Mechanism for Heterogeneous Catalysis

Maximizing Photoelectrochemical Performance in Metal‐Oxide Hybrid Composites via Amorphous Exsolution—A New Exsolution Mechanism for Heterogeneous Catalysis

Amorphous Exsolution of Fe3O4 Nanoparticles in SrTiO3: A Path to High Activity and Stability in Photoelectrochemical Water‐Splitting

Exsolution of Ni nanoparticles in A-site excess STO films

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Amorphous Exsolution of Fe₃O₄ Nanoparticles in SrTiO₃: A Path to High Activity and Stability in Photoelectrochemical Water‐Splitting