CdS quantum dot aerogels for photocatalytic hydrogen evolution  

作　　者：Vinicius Alevato Daniel Streater Cole Premtaj Jier Huang Stephanie L.Brock 

机构地区：[1]Department of Chemistry,Wayne State University,Detroit,MI 48202,USA [2]Department of Chemistry,Marquette University,Milwaukee,WI 53201,USA [3]Department of Chemistry&Shiller Institute for Integrated Science and Society,Boston College,Boston,MA 02467,USA

出　　处：《Nano Research》2024年第12期10292-10301,共10页纳米研究（英文版）

基　　金：supported by NSF Award No.1427926,and the Talos F200X G2 S/TEM that is funded in part through NSF MRI Award No.2018587;supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,under Award Number SC0023324.

摘　　要：CdS quantum dots(QDs)have been extensively studied as photocatalysts and sensitizers for visible-light-driven water reduction.However,their efficiencies are limited by the need to accumulate sufficient redox equivalents to produce_(H2)and consequent photocorrosion associated with slow hole-transfer rates.To address these limitations,we report the formation of CdS QD assemblies(aerogels,AGs)capable of facilitating energy/charge transport between individual QDs,and evaluate their performance as photocatalysts for hydrogen evolution as a function of structure,wurtzite(w-)vs.zincblende(zb-),and different annealing temperatures.The formation of AGs from QDs resulted in increased rates of_(H2)production under visible light illumination:from 1458(QD)to 6650(AG)μmol_(H2)·h^(-1)·g^(-1)on zbCdS and from 1221(QD)to 3325(AG)μmol_(H2)·h^(-1)·g^(-1)on wCdS.This is attributed to exciton delocalization between adjacent QDs facilitating charge/energy transport.Thermal processing of CdS AGs up to 250℃ improved their activity,increasing the degree of exciton delocalization,while annealing them to 300℃ caused sintering of the primary QD particles within the AGs and a decrease in activity associated with loss in surface area.The best photocatalyst,zbCdS AG annealed at 250℃,had an average_(H2)production rate of 13,604±2017μmol_(H2)·h^(-1)·g^(-1),an apparent quantum yield of 2.8%at 425±12.5 nm,and was stable for 2 h before beginning to deactivate due to photocorrosion.This study confirms the potential of CdS AGs as matrixes for the design of more active and stable composite photocatalysts for water splitting.

关 键 词：sol-gel chemistry PHOTOCORROSION apparent quantum yield WURTZITE zinc blende 

分 类 号：TQ427.26[化学工程]