Flux-Assisted Syntheses of Calcium Titanate Powders Codoped with Aluminum, Scandium, and Magnesium for Efficient Photocatalytic Overall Water Splitting

IF 5.5 3区材料科学 Q2 CHEMISTRY, PHYSICAL

ACS Applied Energy Materials Pub Date : 2025-08-07 DOI:10.1021/acsaem.5c01174

Kaori Takagi, Tomoya Ota, Kota Kato, Ryota Tomizawa, Tomoya Nagano, Koji Hayashi, Akira Yamakata, Yoshitaro Nose, Nobuya Machida and Shigeru Ikeda*,

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Abstract

Calcium titanate (CaTiO₃) has attracted interest as a photocatalyst for overall water splitting, but its efficiency remains limited. In this study, CaTiO₃ powders codoped with aluminum (Al³⁺), scandium (Sc³⁺), and magnesium (Mg²⁺) cations were synthesized via a flux-mediated method. XRD and Raman analyses confirmed the formation of single-phase perovskite structures with successful dopant incorporation at the B-site (Ti⁴⁺). Appreciable particle growth was observed in the Al³⁺-doped sample. Codoping with Sc³⁺ significantly reduced particle size but also lowered crystallinity, which hindered photocatalytic activity. Further codoping with Mg²⁺ effectively suppressed the formation of deep-level defects. As a result, the CaTiO₃ powder codoped with Al³⁺, Sc³⁺, and Mg²⁺ (CaTiO₃:Al,Sc,Mg) exhibited the highest photocatalytic activity, achieving an apparent quantum yield (AQY) of 73.8% (at 310 nm). Durability tests showed that degradation occurred primarily on the loaded cocatalysts, not the CaTiO₃ itself. Transient absorption measurements revealed enhanced carrier reactivity due to trap state modulation and improved lifetimes in the CaTiO₃:Al,Sc,Mg sample. Band alignment studies indicated that CaTiO₃ has a more negative conduction band minimum than that of strontium titanate (SrTiO₃). These findings demonstrate that strategic doping significantly enhances the photocatalytic properties of CaTiO₃ for various reactions.

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助熔剂辅助合成与铝、钪、镁共掺杂的钛酸钙粉体用于高效光催化整体水分解

钛酸钙（CaTiO3）作为一种光催化剂引起了人们的兴趣，但其效率仍然有限。本研究以铝（Al3+）、钪（Sc3+）、镁（Mg2+）阳离子共掺杂的CaTiO3粉体为原料，采用助熔剂介导法制备了CaTiO3粉体。XRD和Raman分析证实了b位（Ti4+）掺杂成功形成了单相钙钛矿结构。在Al3+掺杂样品中观察到明显的颗粒生长。与Sc3+共掺杂显著减小了颗粒尺寸，但也降低了结晶度，从而影响了光催化活性。进一步与Mg2+共掺杂可有效抑制深层缺陷的形成。结果表明，共掺杂Al3+、Sc3+和Mg2+的CaTiO3粉末（CaTiO3:Al,Sc,Mg）表现出最高的光催化活性，表观量子产率（AQY）达到73.8%（在310 nm）。耐久性测试表明，降解主要发生在负载的助催化剂上，而不是CaTiO3本身。瞬态吸收测量表明，由于捕获态调制，CaTiO3:Al,Sc，Mg样品的载流子反应性增强，寿命延长。带对准研究表明，CaTiO3具有比钛酸锶（SrTiO3）更负的导带最小值。这些结果表明，策略掺杂显著提高了CaTiO3对各种反应的光催化性能。

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来源期刊

ACS Applied Energy Materials Materials Science-Materials Chemistry

CiteScore

10.30

自引率

6.20%

发文量

1368

期刊介绍： ACS Applied Energy Materials is an interdisciplinary journal publishing original research covering all aspects of materials, engineering, chemistry, physics and biology relevant to energy conversion and storage. The journal is devoted to reports of new and original experimental and theoretical research of an applied nature that integrate knowledge in the areas of materials, engineering, physics, bioscience, and chemistry into important energy applications.