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Abstract Determining suitable dopants with optimized doping concentration is critical to design efficient water splitting photocatalysts. However, there is currently a lack of fundamental knowledge to guide this process. Herein, we examine the impact of Al3+, Mg2+, and Ga3+on the photocatalytic performance of SrTiO3and propose a defect compensation model to understand the doping effect. Doped SrTiO3crystals were grown hydrothermally and treated in molten SrCl2. The hydrogen production rates from 50 catalysts produced in this way were measured with a high‐throughput parallelized and automated photochemical reactor (PAPCR). The investigation revealed that all three dopants significantly enhance the photocatalytic reactivity. According to Brouwer diagrams computed using available reaction constants, the optimum reactivity is achieved when the concentration of acceptor dopants fully compensates the oxygen vacancy donors. The improved reactivity can be attributed to the reduction in free electron concentration, resulting in a space charge layer that is 1000 times longer. Consequently, this situation enhances the number of photogenerated charge carriers capable of being separated by the band bending and transported to the surface.
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Influence of Al‐doped SrTiO 3 cores on hydrogen evolution from SrTiO 3 /TiO 2 core‒shell catalysts
Abstract The hydrogen produced by Al‐doped SrTiO3/TiO2core‒shell catalysts with a range of Al‐doped SrTiO3cores and the same TiO2shell are compared. The study included SrTiO3cores doped with different amounts of Al (0, 1, 2, or 3 mol%) added at different points in the synthesis (prior to or during the molten salt treatment) and at different temperatures (900°C, 1000°C, and 1100°C). It was found that core‒shell catalysts with different cores had hydrogen generation rates that varied by a factor of more than 40 and varied with the processing parameters in the same way as the hydrogen generation rates of the cores alone. The best catalysts had 2 or 3 mol% added Al, added during treatment in a SrCl2molten salt at 1000°C or 1100°C. Because the core absorbs most of the light, its ability to separate and transport photogenerated charge carriers dominates the properties of the core‒shell catalyst. This indicates that, to optimize the properties of core‒shell catalysts, it is essential to optimize the properties of the core. While the shell can be important to protect the core from degradation, it is not as important to the overall reactivity as the core.
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- Award ID(s):
- 2016267
- PAR ID:
- 10581124
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Journal of the American Ceramic Society
- Volume:
- 108
- Issue:
- 8
- ISSN:
- 0002-7820
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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