Near‐Infrared‐Plasmonic Energy Upconversion in a Nonmetallic Heterostructure for Efficient H₂ Evolution from Ammonia Borane

Abstract

Plasmonic metal nanostructures have been widely used to enhance the upconversion efficiency of the near‐infrared (NIR) photons into the visible region via the localized surface plasmon resonance (LSPR) effect. However, the direct utilization of low‐cost nonmetallic semiconductors to both concentrate and transfer the NIR‐plasmonic energy in the upconversion system remains a significant challenge. Here, a fascinating process of NIR‐plasmonic energy upconversion in Yb3+/Er3+‐doped NaYF4 nanoparticles (NaYF4:Yb‐Er NPs)/W18O49 nanowires (NWs) heterostructures, which can selectively enhance the upconversion luminescence by two orders of magnitude, is demonstrated. Combined with theoretical calculations, it is proposed that the NIR‐excited LSPR of W18O49 NWs is the primary reason for the enhanced upconversion luminescence of NaYF4:Yb‐Er NPs. Meanwhile, this plasmon‐enhanced upconversion luminescence can be partly absorbed by the W18O49 NWs to re‐excite its higher energy LSPR, thus leading to the selective enhancement of upconversion luminescence for the NaYF4:Yb‐Er/W18O49 heterostructures. More importantly, based on this process of plasmonic energy transfer, an NIR‐driven catalyst of NaYF4:Yb‐Er NPs@W18O49 NWs quasi‐core/shell heterostructure, which exhibits a ≈35‐fold increase in the catalytic H2 evolution from ammonia borane (BH3NH3) is designed and synthesized. This work provides insight on the development of nonmetallic plasmon‐sensitized optical materials that can potentially be applied in photocatalysis, optoelectronic, and photovoltaic devices.

Near‐Infrared‐Driven Photocatalysts: Design, Construction, and Applications

“…[45] Besides, the localized surface plasmon resonance (LSPR) field can also be used to enhance the emission intensity of the upconversion materials. Dong and co-workers have prepared NaYF 4 : Yb, Er/W 18 O 49 nanowire heterostructures [46] as shown in Figure 4i. Due to the abundant vacancies, W 18 O 49 nanowire have enough free electrons to present LSPR effect [26,[47][48] as confirmed by the SPR absorption peak in the Figure 4j.…”

“…[45] i) SEM image of NaYF 4 : Yb, Er/W 18 O 49 nanowire heterostructures. [46] j) Transmittance spectra of W18O49 nanowires (1), N-W18O49 nanowires (2), wavelength. [46] Eventhough the lanthanide-based upconversion materials can help to activate the photocatalytic systems under the NIR irradiation, there are natural bottlenecks for these photocatalytic systems.…”

Tungsten-based photocatalysts with UV–Vis–NIR photocatalytic capacity: progress and opportunity

“…Complexing tungsten-based photocatalysts with other materials to form novel heterojunctions is also an efficient pathway to adjust the charge carrier concentration and improve the fullspectrum photocatalytic activities. NaYF 4 : Yb 3+ -Er 3+ sensitized W 18 O 49 nanowires exhibit distinct improved catalytic H 2 evolution from ammonia borane (BH 3 NH 3 ) upon irradiation at the wavelength of 980 nm [69]. As shown in Fig.…”

Plasmonic Heterostructure TiO2‐MCs/WO3−x‐NWs with Continuous Photoelectron Injection Boosting Hot Electron for Methane Generation

“…While, in strictly, hydrogen generation from ammonia decomposition do not give direct evidence to show the energy transfer from solar light to chemicals. Then, Zhang et al reported photocatalytic hydrogen generation by plasmonic hot electrons of heterostructural W 18 O 49 /g‐C 3 N 4 under visible–NIR light irradiation . Therefore, nonmetallic plasmonic NPs are promising SPR materials for photocatalysis.…”