Temperature-Controlled Transformation of WO<sub>3</sub> Nanowires into Active Facets-Exposed Hexagonal Prisms toward Efficient Visible-Light-Driven Water Oxidation
Temperature-Controlled Transformation of WO<sub>3</sub> Nanowires into Active Facets-Exposed Hexagonal Prisms toward Efficient Visible-Light-Driven Water Oxidation
复制标题
WO<sub>3</sub> 纳米线温控转变为活性面暴露的六角棱柱，实现高效可见光驱动的水氧化
DOI：
10.1021/acsami.2c22483
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Yagi Masayuki
中科院分区：
文献类型：
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作者：
Chandra Debraj;Katsuki Tomohiro;Tanahashi Yuki;Togashi Takanari;Tsubonouchi Yuta;Hoshino Norihisa;Zahran Zaki N.;Yagi Masayuki
以钨酸和肼为结构导向剂制备的（N2H4） wo3前驱体悬浮液通过调节温度，实现了wo3纳米线（NW-WO3）向六方棱镜（HP-WO3）的转变。在20℃下制备前驱体，然后在550℃下煅烧，制备出宽<100 nm，长3-5 μm的nw - wo3纳米晶体，单斜wo3晶体向（002）和（200）面各向异性生长，纳米线侧面具有随机取向的多晶特征。在45℃下制备前驱体，然后在550℃下煅烧，得到的hp - wo3纳米晶体（直径约500 - 1000 nm）分别在具有单晶特征的六角形棱柱wo3纳米晶体的顶平面和侧矩形表面优先暴露（002）和（020）面。hp - wo3电极在可见光驱动水氧化方面表现出优于nw - wo3电极的光电性能；在420 nm和1.23 V vs RHE下，hp - wo3的入射光子电流转换效率（IPCE）为47%，比nw - wo3电极的15%高出3.1倍。PEC阻抗数据表明，体电子通过具有单向纳米线结构的nw - wo3层比通过具有六角形棱柱结构的hp - wo3层更有效。然而，hp - wo3电极表面的水氧化反应比nw - wo3电极更有效，这是hp - wo3电极具有优异的PEC水氧化性能的重要原因。hp - wo3电极表面有效的水氧化反应是由于活性面（002）的表面分数高，而hp - wo3表面晶界和缺陷较少，从而抑制了表面的电子-空穴复合。
A unique transformation of WO3nanowires (NW-WO3) into hexagonal prisms (HP-WO3) was demonstrated by tuning the temperature of the (N2H4)WO3precursor suspension prepared from tungstic acid and hydrazine as a structure-directing agent. The precursor preparation at 20 °C followed by calcination at 550 °C produced NW-WO3nanocrystals (ca.<100 nm width, 3–5 μm length) with anisotropic growth of monoclinic WO3crystals to (002) and (200) planes and a polycrystalline character with randomly oriented crystallites in the lateral face of nanowires. The precursor preparation at 45 °C followed by calcination at 550 °C produced HP-WO3nanocrystals (ca.500–1000 nm diameter) with preferentially exposed (002) and (020) facets on the top-flat and side-rectangle surfaces, respectively, of hexagonal prismatic WO3nanocrystals with a single-crystalline character. The HP-WO3electrode exhibited the superior photoelectrochemical (PEC) performance for visible-light-driven water oxidation to that for the NW-WO3electrode; the incident photon-to-current conversion efficiency (IPCE) of 47% at 420 nm and 1.23 V vs RHE for HP-WO3was 3.1-fold higher than 15% for the NW-WO3electrode. PEC impedance data revealed that the bulk electron transport through the NW-WO3layer with the unidirectional nanowire structure is more efficient than that through the HP-WO3layer with the hexagonal prismatic structure. However, the water oxidation reaction at the surface for the HP-WO3electrode is more efficient than the NW-WO3electrode, contributing significantly to the superior PEC water oxidation performance observed for the HP-WO3electrode. The efficient water oxidation reaction at the surface for the HP-WO3electrode was explained by the high surface fraction of the active (002) facet with fewer grain boundaries and defects on the surface of HP-WO3to suppress the electron–hole recombination at the surface.