Hou S, Wei ZQ, Dai XC, Huang MH, Xiao FX. General Layer-by-Layer Assembly of Multilayered Photoanodes: Triggering Tandem Charge Transport toward Photoelectrochemical Water Oxidation.
Inorg Chem 2020;
59:7325-7334. [PMID:
32338507 DOI:
10.1021/acs.inorgchem.0c00780]
[Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Modulation of photoinduced charge separation/migration and construction of controllable charge transfer pathway over photoelectrodes have been attracting enduring interest in semiconductor-based photoelectrochemical (PEC) cells but suffer from sluggish charge transport kinetics. Here, we report a general approach to fabricate NP-TNTAs/(TMCs QDs/PSS)n (X = Te, Se, S) photoanodes via a facile and green electrostatic layer-by-layer (LbL) self-assembly strategy, for which transition-metal chalcogenides quantum dots (TMCs QDs) [CdX (X = Se, Te, S)] and poly(sodium 4-styrenesulfonate) (PSS) were periodically deposited on the nanoporous TiO2 nanotube arrays (NP-TNTAs) via substantial electrostatic force, resulting in the continuous charge transfer pathway. NP-TNTAs/(TMCs QDs/PSS)n photoanodes demonstrate significantly enhanced solar-driven photoelectrochemical (PEC) water oxidation activities, relative to NP-TNTAs and TMCs QDs under visible and simulated sunlight irradiation, predominantly because of the suitable energy level configuration between NP-TNTAs and TMCs QDs, unique integration mode, and high-speed interfacial charge separation rate endowed by LbL assembly. The ultrathin PSS intermediate layer functions as "molecule glue" for pinpoint and uniform self-assembly of TMCs QDs on the framework of NP-TNTAs and photosensitization effect of TMCs QDs triggers the unidirectional charge transfer cascade, synergistically boosting the charge separation/transfer efficiency. Our work offers an efficacious approach to craft multilayered photoelectrodes and spur further interest in finely tuning the spatial charge flow in PEC cell for solar-to-hydrogen conversion.
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