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Metal–organic framework (MOF) materials have been extensively incorporated with inorganic semiconductor photocatalysts to improve their photocatalytic activity through an efficient charge transfer process across their heterointerface. In this work, octahedral UiO-66-NH2 MOFs with edge-lengths of 110–330 nm are uniformly decorated on the surface of TiO2 electrospun nanofibers by a traditional solvothermal method combined with activation pretreatment. Before the solvothermal growth of UiO-66-NH2, the TiO2 electrospun nanofibers were activated in NaOH solution to etch the TiO2 surface for allowing the exposure of lattice oxygen. The exposed lattice oxygen on the TiO2 surface could interact with the MOF precursor of Zr4+ ions, thus enabling octahedral UiO-66-NH2 to grow uniformly on the surface of TiO2 nanofibers with an intimate Ti–O–Zr hetero-interface. Such an intimate hetero-interface provides an effective channel for boosting the electron transfer between UiO-66-NH2 and TiO2 in their heterostructure. Thus, the UiO-66-NH2/TiO2(anatase) heterostructures exhibited enhanced photocatalytic activity for H2 production as compared to either TiO2(anatase) nanofibers or UiO-66-NH2 nanooctahedra in the presence of Rhodamine B (RhB) as a sensitizer under visible light irradiation. In particular, the decoration of UiO-66-NH2 nanooctahedra on anatase/rutile mixed TiO2 nanofibers could induce further enhancement of the photocatalytic H2 production. The enhanced photocatalytic activity is attributed to the multi-step continuous interfacial transfer of photoinduced electrons with the way of RhB → UiO-66-NH2 → TiO2(anatase) → TiO2(rutile). [ABSTRACT FROM AUTHOR]

• IR-driven strong plasmonic coupling is achieved on a metal/non-metal heterostructure system consisting of Ag nanorices and W 18 O 49 nanowires. • Plasmonic coupling on Ag/W 18 O 49 heterostructure enhances the local electric fields with magnitudes of 101-104 times of that of incident light. • Resonance excitation not only induces ultrafast electron transfer from W 18 O 49 to Ag, but photothermal effect to increase local temperature. • Upon focused sunlight irradiation, the Ag/W 18 O 49 film shows a remarkable photo/thermal enhancement of catalytic activity for H 2 evolution. Plasmonic coupling between two or more metal nanostructures has attracted significant interest, since this fascinating near-field interaction is more effective for the aggregation/magnification of the incident light intensity compared to normal surface-plasmon-resonance (SPR) of single nanostructures. Herein, we report, for the first time, an IR-driven strong plasmonic coupling in an unusual metal/non-metal heterostructure system. This system is fabricated through random assemblage of Ag nanorices (NRs) onto W 18 O 49 nanowires (NWs) film with F-doped SnO 2 glass as substrate. Through the 3D-finite element simulation, we demonstrate that the plasmonic coupling between Ag NRs and W 18 O 49 NWs significantly enhances the localized electric fields at the "hot spots". This achieved magnitudes of 101-104 times of that of incident light, thus leading to the promoted generation of plasmonic "hot-electrons". Moreover, the resonance excitation of plasmonic coupling on the heterostructures not only induces ultrafast electron transfer from W 18 O 49 to Ag hetero-components, but also the photothermal effect to increase the localized temperature. Upon SPR-coupling excitation, the Ag/W 18 O 49 heterostructures film exhibits a remarkable enhancement of the photo/thermal catalytic activity for H 2 evolution from ammonia borane compared to that of either the Ag NRs (˜8.2 ×) or W 18 O 49 NWs (˜9.0 ×) films. Notably, we observed an obvious H 2 evolution over the Ag/W 18 O 49 heterostructures film under natural sunlight irradiation. [ABSTRACT FROM AUTHOR]

Plasmonic nanostructures have received significant attention in the field of solar-to-fuels conversion, because they can collect and utilize abundant low-energy photons to generate high-energy hot electrons for producing green chemical fuels. However, the ultrafast relaxation process of hot electron often leads to poor quantum yields of plasmonic nanostructures. Herein, we construct the one-dimensional W 18 O 49 /Carbon heterostructure for employing low-cost electrospun carbon fibers as the “electron mediator” to hinder the relaxation of hot electron in plasmonic W 18 O 49 nanowires. We confirm that the IR-excited plasmonic hot electrons in W 18 O 49 nanowires can quickly transfer to carbon fibers within only ∼50 fs in the W 18 O 49 /C heterostructure. This kinetics time is much shorter than the relaxation time of these hot electrons from high-energy surface plasmon (SP) to the ground state in W 18 O 49 nanowires (∼5.5 ps). As a result, upon low-energy IR-light excitation, the W 18 O 49 /C heterostructures exhibit nearly 2-fold enhancement on the catalytic H 2 production from ammonia borane as compared to single W 18 O 49 nanowires. Wavelength-dependent catalytic tests further indicate that this plasmon-enhanced catalytic activity is induced by the ultrafast transport process of plasmonic hot electron due to the localized surface plasmon resonance. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production is enchanting in solar energy utilization. And mechanism elucidation in interfacial electron transfer rate is a prerequisite for performance improvement. Herein, atomically dispersed Pt-modified CdS quantum dots (Pt-CdS QDs), prepared by a facile one-step in-situ deposited method, are used as a prototype. Benefiting from the maximized utilization of Pt cocatalyst as well as the strong electronic metal-support interaction, ultrafast electron transfer from CdS to Pt (∼1.7 ps) is achieved, as revealed by femtosecond transient absorption spectra. The optimal sample simultaneously realizes photocatalytic hydrogen evolution coupled with selective oxidation of 2-thiophene methanol (TM) into 2-thiophenecarboxaldehyde (TD). Specifically, it exhibits an enhanced H 2 -evolution rate, which is 70-fold higher than pristine CdS QDs. Moreover, a TM conversion rate of 95.3 % with a TD selectivity of 87.2 % is reached after 4 h. This work will provide some guidance for the design of photocatalytic systems with efficient interfacial electron transfer. [Display omitted] • Atomically-dispersed Pt-modified CdS quantum dots were prepared. • A facile one-step approach was used for the synthesis of photocatalysts. • Enhanced H 2 production coupled with selective oxidation of 2-thiophene methanol. • Both photogenerated electrons and holes are efficiently utilized through this system. • Ultrafast electron transfer from CdS to Pt (∼1.7 ps) is revealed. [ABSTRACT FROM AUTHOR]