Electronically-Coupled Phase Boundaries in α-Fe2O3/Fe3O4 Nanocomposite Photoanodes for Enhanced Water Oxidation
Electronically-Coupled Phase Boundaries in α-Fe2O3/Fe3O4 Nanocomposite Photoanodes for Enhanced Water Oxidation
复制标题
DOI：
10.1021/acsanm.8b01936
复制
发表时间：
2019-01-01
影响因子：
5.9
通讯作者：
Mathur, Sanjay
中科院分区：
文献类型：
--
作者：
Leduc, Jennifer;Goenuellue, Yakup;Mathur, Sanjay
光电化学（PEC）水分解反应有望用于利用可再生资源可持续生产氢气。我们在此报告，通过 [Fe((OBu)-Bu-t)(3)](2) 的一步化学气相沉积制备 α-Fe2O3/Fe3O4 复合薄膜，并将其用作 PEC 设置中的高效光阳极材料。通过改变沉积时间来控制薄膜厚度和相分离，并通过截面拉曼光谱和扫描电子显微镜进行证实。使用间歇 AM 1.5 G (100 mW/cm(2)) 标准照明时，发现厚度为 11 μm 的混合薄膜具有最高的水氧化活性（1.23 V vs RHE 下为 0.48 mA/cm(2)）。这种现象归因于由于朝向基底界面的磁铁矿含量较高而导致电子传输的改善以及由于赤铁矿层主要位于薄膜的顶表面而导致的光吸收增加。观察到的α-Fe2O3/Fe3O4纳米复合光阳极的高效率归因于弱铁（Fe2O3）和亚铁磁性（Fe3O4）氧化物之间的紧密接近和3D界面的建立，鉴于它们不同的化学组成和Fe离子（Fe2+/Fe3+）的价态可以增强电荷分离，从而增强该层的整体电导率。
Photoelectrochemical (PEC) water splitting reactions are promising for sustainable hydrogen production from renewable sources. We report here, the preparation of alpha-Fe2O3/Fe3O4 composite films via a single-step chemical vapor deposition of [Fe((OBu)-Bu-t)(3)](2) and their use as efficient photoanode materials in PEC setups. Film thickness and phase segregation was controlled by varying the deposition time and corroborated through cross-section Raman spectroscopy and scanning electron microscopy. The highest water oxidation activity (0.48 mA/cm(2) at 1.23 V vs RHE) using intermittent AM 1.5 G (100 mW/cm(2)) standard illumination was found for hybrid films with a thickness of 11 mu m. This phenomenon is attributed to an improved electron transport resulting from a higher magnetite content toward the substrate interface and an increased light absorption due to the hematite layer mainly located at the top surface of the film. The observed high efficiency of alpha-Fe2O3/Fe3O4 nanocomposite photoanodes is attributed to the close proximity and establishment of 3D interfaces between the weakly ferro- (Fe2O3) and ferrimagnetic (Fe3O4) oxides, which in view of their differential chemical constitution and valence states of Fe ions (Fe2+/Fe3+) can enhance the charge separation and thus the overall electrical conductivity of the layer.