Wang Lei, Nguyen Nhat Truong, Zhang Yajun, Bi Yingpu, Schmuki Patrik
State Key Laboratory for Oxo Synthesis and Selective Oxidation, National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, CAS, 730000, Lanzhou, PR China.
Department of Materials Science and Engineering, WW4-LKO, University of Erlangen-Nuremberg, Martensstrasse 7, 91058, Erlangen, Germany.
ChemSusChem. 2017 Jul 10;10(13):2720-2727. doi: 10.1002/cssc.201700522. Epub 2017 Jun 8.
In this work, single crystalline α-Fe O nanoflakes (NFs) are formed in a highly dense array by Au seeding of a Fe substrate by a thermal oxidation technique. The NFs are conformally decorated with a thin FeOOH cocatalyst layer. Photoelectrochemical (PEC) measurements show that this photoanode, incorporating α-Fe O /FeOOH NFs rooted on the Au/Fe structure, exhibits significantly enhanced PEC water oxidation performance compared to the plain α-Fe O nanostructure on the Fe substrate. The α-Fe O /FeOOH NFs on Au/Fe photoanode yields a photocurrent density of 3.1 mA cm at 1.5 V , and a remarkably low onset potential of 0.5-0.6 V in 1 m KOH under AM 1.5G (100 mW cm ) simulated sunlight illumination. The enhancement in PEC performance can be attributed to a synergistic effect of the FeOOH top decoration and the Au underlayer, whereby FeOOH facilitates hole transfer at the interface of electrode/electrolyte and the Au layer provides a sink for the electron transport to the back contact. This results in a drastically improved charge-separation efficiency in the single crystalline α-Fe O NF photoanode.
在本工作中，通过热氧化技术对铁基底进行金种子处理，形成了高密度排列的单晶α-Fe₂O₃纳米片（NFs）。这些纳米片被一层薄的FeOOH助催化剂层保形修饰。光电化学（PEC）测量表明，这种基于Au/Fe结构且含有α-Fe₂O₃/FeOOH NFs的光阳极，与铁基底上的普通α-Fe₂O₃纳米结构相比，其PEC水氧化性能显著增强。Au/Fe光阳极上的α-Fe₂O₃/FeOOH NFs在1.5 V时产生的光电流密度为3.1 mA/cm²，在AM 1.5G（100 mW/cm²）模拟太阳光照射下，在1 M KOH中起始电位低至0.5 - 0.6 V。PEC性能的增强可归因于FeOOH顶部修饰和金底层的协同效应，其中FeOOH促进了电极/电解质界面处的空穴转移，而金层为电子传输到背接触提供了一个汇。这导致单晶α-Fe₂O₃ NF光阳极中的电荷分离效率大幅提高。
