界面 Se-O 键通过快速空穴提取调节 FeSe2/Nb:Fe2O3 中的空间电荷分布，实现高效光电化学水氧化,ACS Applied Materials & Interfaces

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界面 Se-O 键通过快速空穴提取调节 FeSe2/Nb:Fe2O3 中的空间电荷分布，实现高效光电化学水氧化
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2023-11-30 , DOI: 10.1021/acsami.3c12007
Lili Gao ₁ , Jiaoli Wang ₁ , Huilin Niu ₁ , Jun Jin ₁ , Jiantai Ma _{1,

2}

Affiliation

表面工程是提高赤铁矿光电化学（PEC）催化活性的有效策略，具有丰富配位不饱和原子的缺陷态可以作为在半导体之间构建紧密连接的锚定位点。在此基础上，我们通过界面Se-O化学键将超薄FeSe ₂层锚定在Nb ⁵⁺掺杂的Fe ₂ O ₃ (FeSe ₂ /Nb:Fe ₂ O _{3 )上以调节表面电位。}密度泛函理论（DFT）计算表明，非晶FeSe ₂修饰可以在复合光阳极上产生电子离域，从而在很大程度上提高电子迁移率。此外，电子可以通过界面处新形成的Se-O键转移，并且空穴被收集在电极表面，用于PEC水氧化。所需的电荷重新分布有利于抑制电荷复合和提取有效空穴。随后，功函数计算和莫特-肖特基（M-S）图表明，FeSe ₂ /Nb:Fe ₂ O ₃中形成了II型异质结，这进一步加速了载流子分离。根据d带中心结果，除了空间载流子调制之外，非晶FeSe _{2层还为中间体吸附提供了丰富的活性位点。}结果，与可逆氢电极（RHE）相比，目标光阳极在1.23 V下获得了2.42 mA cm ^–2的改进光电流密度，是裸Fe ₂ O ₃的2.5倍。本研究提出了一种通过界面化学键生长紧密连接层的缺陷锚定方法，并揭示了FeSe ₂对Nb:Fe ₂ O ₃的空间电荷分布效应，为复合光阳极的合理设计提供了见解。

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Interfacial Se–O Bonds Modulating Spatial Charge Distribution in FeSe2/Nb:Fe2O3 with Rapid Hole Extraction for Efficient Photoelectrochemical Water Oxidation

Surface engineering is an effective strategy to improve the photoelectrochemical (PEC) catalytic activity of hematite, and the defect states with abundant coordinative unsaturation atoms can serve as anchoring sites for constructing intimate connections between semiconductors. On this basis, we anchored an ultrathin FeSe₂ layer on Nb⁵⁺-doped Fe₂O₃ (FeSe₂/Nb:Fe₂O₃) via interfacial Se–O chemical bonds to tune the surface potential. Density functional theory (DFT) calculations indicate that amorphous FeSe₂ decoration could generate electron delocalization over the composite photoanodes so that the electron mobility was improved to a large extent. Furthermore, electrons could be transferred via the newly formed Se–O bonds at the interface and holes were collected at the surface of electrode for PEC water oxidation. The desired charge redistribution is in favor of suppressing charge recombination and extracting effective holes. Later, work function calculations and Mott–Schottky (M–S) plots demonstrate that a type-II heterojunction was formed in FeSe₂/Nb:Fe₂O₃, which further expedited carrier separation. Except for spatial carrier modulation, the amorphous FeSe₂ layer also provided abundant active sites for intermediates adsorption according to the d band center results. In consequence, the target photoanodes attained an improved photocurrent density of 2.42 mA cm^–2 at 1.23 V versus the reversible hydrogen electrode (RHE), 2.5 times as that of the bare Fe₂O₃. This study proposed a defect-anchoring method to grow a close-connected layer via interfacial chemical bonds and revealed the spatial charge distribution effects of FeSe₂ on Nb:Fe₂O₃, giving insights into rational designation in composite photoanodes.

更新日期：2023-11-30

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