Heterostructures of Ni(II)-doped CdS quantum dots andβ-Pb_(0.33)V_(2)O_(5)nanowires:Enhanced charge separation and redox photocatalysis via doping of QDs  

作　　者：Karoline E.García-Pedraza Jaime R.Ayala Udani Wijethunga Alice R.Giem George Agbeworvi Sarbajit Banerjee David F.Watson 

机构地区：[1]Department of Chemistry,University at Buffalo,The State University of New York,Buffalo,New York 14260-3000,USA [2]Department of Chemistry,Texas A&M University,College Station,Texas 77843,USA [3]Department of Materials Science and Engineering,Texas A&M University,College Station,Texas 77843,USA

出　　处：《Nano Research》2024年第12期10279-10291,共13页纳米研究（英文版）

基　　金：supported by the NSF under DMREF 1626967 and 1627197;funded in part by award A-1978-20220331 from the Welch Foundation;performed using resources of the Center for Functional Nanomaterials,which is a U.S.DOE Office of Science Facility,at Brookhaven National Laboratory under contract DESC0012704。

摘　　要：We synthesized heterostructures by tethering Ni(II)-doped CdS(Ni:CdS)quantum dots(QDs)toβ-Pb_(0.33)V_(2)O_(5)nanowires(NWs)using L-cysteine as a molecular linker,and we evaluated the influence of doping on their redox photocatalytic reactivity.We initially hypothesized that incorporating Ni:CdS QDs into heterostructures could alter excited-state dynamics and mechanisms,and that the localization of excited electrons on Ni 3d states could promote redox photocatalytic mechanisms including reduction of CO_(2).Isolated Ni:CdS QDs were ferromagnetic,and they exhibited enhanced photocatalytic hydrogen evolution and photostability relative to undoped CdS QDs.Both Pb_(0.33)V_(2)O_(5)/CdS heterostructures(with undoped QDs)and Pb_(0.33)V_(2)O_(5)/Ni:CdS heterostructures(with Ni(II)-doped QDs)exhibited substantial energetic overlap between valence-band states of QDs and intercalative mid-gap states ofβ-Pb_(0.33)V_(2)O_(5)NWs.Within Pb_(0.33)V_(2)O_(5)/CdS heterostructures,photoexcitation of CdS QDs was followed by rapid(50-100 ps)transfer of both holes and electrons toβ-Pb_(0.33)V_(2)O_(5)NWs.In contrast,within Pb_(0.33)V_(2)O_(5)/Ni:CdS heterostructures,holes were transferred from Ni:CdS QDs toβ-Pb_(0.33)V_(2)O_(5)NWs within 100 ps,but electrons were transferred approximately 20-fold more slowly.This difference in electron-and hole-transfer kinetics promoted charge separation across the Pb_(0.33)V_(2)O_(5)/Ni:CdS interface and enabled the photocatalytic reduction of CO_(2)to CO,CH_(4),and HCO_(2)H with>99.9%selectivity relative to the reduction of H+to H2.These results highlight the opportunity to fine-tune dynamics and mechanisms of excitedstate charge-transfer,and mechanisms of subsequent redox half-reactions,by doping QDs within heterostructures.Moreover,they reveal the promise of heterostructures comprising QDs and MxVyO5 materials as CO_(2)-reduction photocatalysts.

关 键 词：HETEROSTRUCTURES PHOTOCATALYSIS CO_(2)reduction quantum dots metal vanadates charge transfer 

分 类 号：TB383[一般工业技术—材料科学与工程]