Phenomenological Understanding of Hematite Photoanode Performance
Phenomenological Understanding of Hematite Photoanode Performance
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DOI：
10.1021/acs.jpcc.0c11420
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发表时间：
2021-04-09
影响因子：
3.7
通讯作者：
Seixas de Melo, Joao Sergio
中科院分区：
文献类型：
--
作者：
Pina, Joao;Dias, Paula;Seixas de Melo, Joao Sergio
利用光电化学和瞬态吸收光谱研究了赤铁矿光阳极的结构和电子性质对载流子动力学的影响。采用喷雾热解法和水热法制备了不同厚度、形貌、掺杂剂和表面处理的赤铁矿光电极。TAS分析使用独立光电极、三电极配置和操作中进行。TAS研究表明，在最初的几百皮秒内有一个显着的电子-空穴复合和较长寿命的电荷载流子的较小幅度，这是光电化学测量中观察到的产生的光电流的原因。性能最好的光电极是在800 ℃下退火并涂覆有IrO 2/RuO 2助催化剂和Ti掺杂的赤铁矿纳米线的Sn掺杂的赤铁矿薄膜。表面处理的效果，即，高温退火负责Sn本征掺杂和助催化剂涂层，对电子-空穴复合动力学在皮秒时间尺度上是可以忽略的。TAS研究表明，钛掺入后，电子-空穴复合较慢，电子密度增加，表面积增大。
The effect of the structural and electronic properties of hematite photoanodes on the charge carrier dynamics was investigated by photoelectrochemistry and transient absorption spectroscopy (TAS). Hematite photoelectrodes were prepared by spray pyrolysis and hydrothermal methods for obtaining films with different thicknesses, morphologies, doping agents, and surface treatments. TAS analyses were performed using standalone photoelectrodes, a three-electrode configuration and in operando. TAS studies revealed that there is a significant electron-hole recombination within the first few hundred picoseconds and smaller amplitude of longer-lived charge carriers, which are responsible for the generated photocurrent observed in photoelectrochemical measurements. The best performing photoelectrodes are Sn-doped hematite thin film annealed at 800 degrees C and coated with IrO2/RuO2 co-catalyst and the Ti-doped hematite nanowires. The effect of surface treatments, i.e., high-temperature annealing responsible for Sn intrinsic doping and co-catalyst coating, on the electron-hole recombination dynamics is negligible at the picosecond time scale. The TAS studies showed a slower electron-hole recombination after Ti incorporation, increased electron density, and enlarged surface area.