Augmenting the donor density and nanostructure engineering are the crucial points to improve solar water oxidation performance of hematite (α-Fe2O3). This work addresses the sluggish water oxidation reaction associated with hematite photoanode by tweaking its internal porosity. The porous hematite photoanodes are fabricated by a novel synthetic strategy via pulse reverse electrodeposition (PRED) method that involves incorporation of a cationic CTAB surfactant in a sulfate electrolyte and spin-coated ZrO2 underlayer (UL) on FTO. CTAB is found to be beneficial in promoting the film growth rate during PRED. Incorporation of Zr(4+) ions from ZrO2 UL and Sn(4+) ions from FTO into the Fe2O3 lattice via solid-state diffusion reaction during pertinent annihilation of surfactant molecules at 800 °C produced internally porous hematite films with improved carrier concentration. The porous hematite demonstrated a sustained photocurrent enhancement and a significant cathodic shift of 130 mV relative to the planar hematite under standard illumination conditions (AM 1.5G) in 1 M NaOH electrolyte. The absorption, electrochemical impedance spectroscopy and Mott-Schottky analyses revealed that the ZrO2 UL and CTAB not only increased the carrier density and light harvesting but also accelerated the surface oxidation reaction kinetics, synergistically boosting the performance of internally porous hematite photoanodes.

中文翻译：

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表面活性剂和ZrO2底层对纳米多孔Fe2O3光电阳极的光电流增强和阴极迁移的协同作用。

提高施主密度和纳米结构工程是改善赤铁矿（α-Fe2O3）的太阳能氧化性能的关键点。这项工作通过调整其内部孔隙率解决了与赤铁矿光阳极相关的缓慢的水氧化反应。多孔赤铁矿光阳极通过脉冲逆电沉积（PRED）方法通过新颖的合成策略制备，该方法包括在硫酸盐电解质中掺入阳离子CTAB表面活性剂并在FTO上旋涂ZrO2底层（UL）。发现CTAB有利于提高PRED期间的膜生长速率。在表面活性剂分子于800°C进行适当的an灭过程中，通过固态扩散反应将ZrO2 UL的Zr（4+）离子和FTO的Sn（4+）离子掺入Fe2O3晶格中，从而制得了内部多孔赤铁矿膜，其载流子浓度得到了改善。相对于平面赤铁矿，在标准光照条件下（AM 1.5G）在1 M NaOH电解质中，多孔赤铁矿表现出持续的光电流增强和130 mV的显着阴极位移。吸收，电化学阻抗谱和Mott-Schottky分析表明，ZrO2 UL和CTAB不仅增加了载流子密度和光收集，而且还加速了表面氧化反应动力学，从而协同提高了内部多孔赤铁矿光阳极的性能。相对于平面赤铁矿，在标准光照条件下（AM 1.5G）在1 M NaOH电解质中，多孔赤铁矿表现出持续的光电流增强和130 mV的显着阴极位移。吸收，电化学阻抗谱和Mott-Schottky分析表明，ZrO2 UL和CTAB不仅增加了载流子密度和光收集，而且还加速了表面氧化反应动力学，从而协同提高了内部多孔赤铁矿光阳极的性能。相对于平面赤铁矿，在标准光照条件下（AM 1.5G）在1 M NaOH电解质中，多孔赤铁矿表现出持续的光电流增强和130 mV的显着阴极位移。吸收，电化学阻抗谱和Mott-Schottky分析表明，ZrO2 UL和CTAB不仅增加了载流子密度和光收集，而且还加速了表面氧化反应动力学，从而协同提高了内部多孔赤铁矿光阳极的性能。