摘要
Developing new catalysts to decorate photoelectrodes has been widely used to enhance the performance of photoelectrochemical(PEC)cells.However,the high cost,complex synthesis,and poor stability of catalyst decoration strongly hinder its practical application.Here,we report a facile and low-cost decoration of Ag-Pt nanoparticles(Ag-Pt NPs)on Si photocathodes with TiO_(2)/Ti sacrificial overlayers.Such a decoration does not rely on any metallic-ion precursor solution since it is formed automatically via galvanic replacement reactions during PEC measurements;that is,Ti is displaced by Ag^(+)and Pt^(2+)ions,which are from the employed reference and counter electrodes,respectively.The as-decorated Ag-Pt NPs are verified to significantly enhance the hydrogen evolution reduction kinetics without substantially degrading the optical performance of Si photocathodes.Owing to optoelectronic advantages,the overpotential required to maintain a photocurrent density of 10 mA cm(under AM1.5 G illumination)is reduced from-0.8 V_(RHE)(for the bare planar Si photocathode)to-0.1 V_(RHE)(for the planar Si photocathode with Ag-Pt NP decoration).Moreover,a further anodic shift(to 0 V_(RHE))is visible for the Si nanowire array photocathode with Ag-Pt NP decoration,along with high long-term stability of the PEC response in acidic and neutral electrolytes.This study opens a new opportunity for the photo-assisted decoration of various alloy NPs on the morphology-varying photoelectrodes with different applications.
为了提高光电化学(PEC)电池的性能,用于修饰光电极的各类新型催化剂已被广泛研究和试用.然而,在光电极表面修饰高性能催化剂的成本高、过程复杂、稳定性差,这些问题严重阻碍了其实际应用.在本研究中,我们提出了一种Ag-Pt合金纳米颗粒(Ag-Pt NPs)修饰光电极的策略,即将TiO_(2)/Ti牺牲层覆盖的硅光阴极置入三电极电化学测试体系中进行有光照的多次线性电势扫描.本修饰方法不需使用含有金属离子的前驱体溶液,只需用到酸性背景液、可重复使用的Pt对电极和Ag/AgCl参比电极,即可通过金属Ti与溶解(或扩散)至溶液中的Pt^(2+)/Ag^(+)离子间的光辅助置换反应而形成Ag-Pt合金.经实验验证,修饰了Ag-Pt纳米颗粒的硅光阴极的析氢反应动力学可得到显著增强,同时其光吸收性能不会出现明显降低.在一个太阳的模拟光照下,未修饰的平面硅光阴极维持10 mA cm^(-2)的光电流密度所需过电势在经过Ag-Pt NPs修饰后可从-0.8 V_(RHE)降低至-0.1 V_(RHE),而对修饰了Ag-Pt NPs的硅纳米线阵列光阴极而言,其过电势可低至0 V_(RHE).此外,还证明了Ag-Pt NPs修饰的光阴极在酸性和中性介质中均表现出显著增强的光化学分解水性能和优异的稳定性.本研究为不同形貌的光电极上合金纳米颗粒的修饰提供了新的思路和方法.
作者
Liujing Li
Tingting Liu
Zhongyuan Zhou
Peiji Guo
Xiaofeng Li
Shaolong Wu
李刘晶;刘婷婷;周忠源;郭培基;李孝峰;吴绍龙(School of Optoelectronic Science and Engineering&Collaborative Innovation Center of Suzhou Nano Science and Technology,Soochow University,Suzhou 215006,China;Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province&Key Lab of Modern Optical Technologies of Education Ministry of China,Soochow University,Suzhou 215006,China;School of Chemical and Environmental Engineering,Anyang Institute of Technology,Anyang 455000,China)
基金
supported by the National Natural Science Foundation of China(62075146 and 61875143)
the Natural Science Foundation of Jiangsu Province(BK20181169)
the Natural Science Foundation of Jiangsu Higher Education Institutions(20KJA510003)
Qinglan Project of Jiangsu Province
the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions
the Natural Science Research of Jiangsu Higher Education Institutions。
