Han Sangmoon, Noh Siyun, Yu Yeon-Tae, Lee Cheul-Ro, Lee Seoung-Ki, Kim Jin Soo
Department of Electronic and Information Materials Engineering, Division of Advanced Materials Engineering, and Research Center of Advanced Materials Development, Jeonbuk National University, Jeonju 54896, South Korea.
Applied Quantum Composites Research Center, Korea Institute of Science and Technology, Wanju 55324, South Korea.
ACS Appl Mater Interfaces. 2020 Dec 30;12(52):58028-58037. doi: 10.1021/acsami.0c17811. Epub 2020 Dec 18.
In the present study, we have achieved high-performance photoelectrochemical water splitting (PEC-WS) using GaN nanowires (NWs) coated with tungsten sulfide (WS) (GaN-NW-WS) as a photoanode. The measured current density and applied-bias photon-to-current efficiency were 20.38 mA/cm and 13.76%, respectively. These values were much higher than those reported previously for photoanodes with any kind of III-nitride nanostructure. The amount of hydrogen gas formed was 1.01 mmol/cm from 7 h PEC-WS, which was also much higher than the previously reported values. The drastic improvement in the PEC-WS performance using the GaN-NW-WS photoanode was attributed to an increase in the number of photogenerated carriers due to the highly crystalline GaN NWs, and acceleration of separation of photogenerated carriers and consequent suppression of charge recombination because of nitrogen-terminated surfaces of NWs, sulfur vacancies in WS, and type-II band alignment between NW and WS. The degree of impedance matching, evaluated from Nyquist plots, was considered to analyze charge transfer characteristics at the interface between the GaN-NW-WS photoanode and 0.5-M HSO electrolyte. Considering the material system and scheme for the PEC-WS, our approach provides an efficient way to improve hydrogen evolution reaction.
在本研究中，我们使用涂有硫化钨（WS）的氮化镓纳米线（NWs）（GaN-NW-WS）作为光阳极实现了高性能光电化学水分解（PEC-WS）。测得的电流密度和施加偏压下的光子到电流效率分别为20.38 mA/cm²和13.76%。这些值远高于先前报道的任何类型的III族氮化物纳米结构光阳极的值。通过7小时的PEC-WS形成的氢气量为1.01 mmol/cm²，这也远高于先前报道的值。使用GaN-NW-WS光阳极使PEC-WS性能得到显著改善，这归因于高度结晶的GaN纳米线导致光生载流子数量增加，以及由于纳米线的氮端表面、WS中的硫空位和NW与WS之间的II型能带排列，加速了光生载流子的分离并因此抑制了电荷复合。从奈奎斯特图评估的阻抗匹配程度被认为可用于分析GaN-NW-WS光阳极与0.5 M H₂SO₄电解质之间界面处的电荷转移特性。考虑到PEC-WS的材料体系和方案，我们的方法为改善析氢反应提供了一种有效的途径。
