物理化学学报2019，Vol.35Issue(2)：215-222,8.DOI:10.3866/PKU.WHXB201803061
表面缺陷与钯的沉积对硫化镉纳米晶粒的光催化制氢性能的影响
Influence of Surface Defects and Palladium Deposition on the Activity of CdS Nanocrystals for Photocatalytic Hydrogen Production
摘要
Abstract
The development of the photocatalytic production of hydrogen from water splitting has attracted immense attention in recent years.CdS is a potential photocatalyst with a visible light response,though it still suffers from a limited activity for hydrogen production due to the fast recombination of photo-induced electron/hole pairs and the low reaction rate of hydrogen evolution on the surface.Studies on the effect of CdS surface structure and properties on hydrogen production are still very limited.In this work,we prepared three CdS nanocrystals with different morphologies:long rod,short rod,and triangular plate.The prepared samples were well characterized by transmission electron microscopy(TEM),X-ray diffraction(XRD),Brunauer-Emmett-Teller(BET)specific surface area analysis,X-ray photoelectron spectroscopy(XPS),photoluminescence(PL) spectroscopy,and UV-Vis diffuse reflectance spectroscopy(UV-Vis DRS).From the results of TEM,XRD and XPS,we find that the three CdS nanocrystals with different morphologies were successfully synthesized.From the PL spectra,we conclude that the area of exposed nonpolar surface and degree of surface defects increase with an increase in aspect ratio.We also performed the photocatalytic hydrogen production reaction using the three CdS crystals.Long rod-like CdS (lr-CdS)exhibits the highest photocatalytic activity,with a hydrogen production rate of 482 μmol.h-1.g-1,which is 2.6 times that of short rod-like CdS(sr-CdS)(183 μmol.h-1.g-1)and 8.8 times that of triangular plate-like CdS(tp-CdS,55 pmolh-1.g-1).It is found that lr-CdS shows a higher hydrogen production rate than sr-CdS and tp-CdS.We find that the hydrogen production rate is related to the degree of surface defects.Surface defects can trap the photo-induced electrons/holes,thus decreasing their probability of recombination.In addition,these defects can be used to anchor Pd particles to form a heterojunction structure that facilitates the separation of photo-induced charges.Therefore,we also compared three CdS/Pd nanocrystals synthesized with the three abovementioned morphologies with respect to hydrogen production.With 1%(W,mass fraction)Pd,the hydrogen production rate was greatly enhanced compared to all the CdS catalysts.Compared to the unpromoted CdS,the reaction rate is enhanced 43.1,10.7 and 6.0 times over those of sr-CdS,lr-CdS and tp-CdS,respectively.Notably,the hydrogen production rate with short rod-like CdS/Pd reaches 7884 μmol.h-1.g-1,which can be favorably compared with the ever-increasing values reported in the literature.Hopefully,this work provides knowledge on the effect of crystal surface structure and properties on photocatalysis.关键词
CdS纳米晶体/光催化制氢/表面缺陷/异质结/Pd促进作用Key words
CdS nanocrystal/Photocatalytic hydrogen production/Surface defects/Heterojunction structure/Pd promotion分类
化学化工引用本文复制引用
刘志明,刘国亮,洪昕林..表面缺陷与钯的沉积对硫化镉纳米晶粒的光催化制氢性能的影响[J].物理化学学报,2019,35(2):215-222,8.基金项目
国家自然科学基金(21373153)资助项目 （21373153）
The project was supported by the National Natural Science Foundation of China (21373153) （21373153）
