Ti掺杂的WO_(3)纳米片光阳极的能带调控和光电化学分解水性能

Band gap modulation of nanostructured WO_(3) nanoplate film by Ti doping for enhanced photoelectrochemical performance

氧化钨(WO_(3))是一种重要的光电化学分解水半导体,具有可见光响应好、无毒、稳定性好等优点,但低的电导率、高的起始电位以及缓慢的水氧化动力学等缺点也限制了其进一步应用。本文采用无晶种水热法在导电玻璃(FTO)上设计了一种钛掺杂的WO_(3)纳米片阵列,并研究了Ti掺杂浓度对光电化学分解水性能的影响。结果表明,在0.6 V(vs Ag/AgCl)的偏压下,Ti掺杂WO_(3)光电流密度最高,可达0.53 mA/cm^(2),比纯WO_(3)纳米片阵列的高110%。同时,Ti掺杂WO_(3)光电极的起始电位负移。X射线光电子能谱价带谱(XPS-VB)和紫外-可见吸收(UV-Vis)光谱显示,Ti掺杂WO_(3)光阳极的能带位置向上移动,导致了起始电位的负移。此外,电化学阻抗谱测试(EIS)表明,Ti掺杂WO_(3)光阳极的导电性显著增强,引起光生载流子的快速分离。研究成果有望提供一种高效、低成本光阳极的设计路线。

Despite being a promising photoanode material for water splitting,WO_(3) has low conductivity,high onset potential,and sluggish water oxidation kinetics.In this study,we designed Ti-doped WO_(3) nanoplate arrays on fluoride-doped tin oxide by a seed-free hydrothermal method,and the effects of doping on the photoelectrochemical performance were investigated.The optimal Ti-doped WO_(3) electrode achieved a photocurrent density of 0.53 mA/cm^(2) at 0.6 V(vs Ag/AgCl),110%higher than that of pure WO_(3) nanoplate arrays.Moreover,a significant cathodic shift in the onset potential was observed after doping.X-ray photoelectron spectroscopy valence band and ultraviolet–visible spectra revealed that the band positions of Ti-doped WO_(3) photoanodes moved upward,yielding a lower onset potential.Furthermore,electrochemical impedance spectroscopy measurements revealed that the conductivities of the WO_(3) photoanodes improved after doping,because of the rapid separation of photo-generated charge carriers.Thus,we report a new design route toward efficient and low-cost photoanodes for photoelectrochemical applications.