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Surface plasmon resonance-induced charge separation plays key roles in plasmon-related applications, especially in photocatalysis and photovoltaics. Plasmon coupling nanostructures exhibit extraordinary behaviors in hybrid states, phonon scattering, and ultrafast plasmon dephasing, but plasmon-induced charge separation in these materials remains unknown. Here, we design Schottky-free Au nanoparticle (NP)/NiO/Au nanoparticles-on-a-mirror plasmonic photocatalysts to support plasmon-induced interfacial hole transfer, evidenced by surface photovoltage microscopy at the single-particle level. In particular, we observe a nonlinear increase in charge density and photocatalytic performance with an increase in excitation intensity in plasmonic photocatalysts containing hot spots as a result of varying the geometry. Such charge separation increased the internal quantum efficiency by 14 times at 600 nm in catalytic reactions as compared to that of the Au NP/NiO without a coupling effect. These observations provide an improved understanding of charge transfer management and utilization by geometric engineering and interface electronic structure for plasmonic photocatalysis.
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Metal halide perovskites (MHPs) have emerged as attractive candidates for producing green hydrogen via photocatalytic pathway. However, the presence of abundant defects and absence of efficient hydrogen evolution reaction (HER) active sites on MHPs seriously limit the solar-to-chemical (STC) conversion efficiency. Herein, to address this issue, we present a bi-functionalization strategy through decorating MHPs with a molecular molybdenum-sulfur-containing co-catalyst precursor. By virtue of the strong chemical interaction between lead and sulfur and the good dispersion of the molecular co-catalyst precursor in the deposition solution, a uniform and intimate decoration of the MHPs surface with lead sulfide (PbS) and amorphous molybdenum sulfide (MoSx) co-catalysts is obtained simultaneously. We show that the PbS co-catalyst can effectively passivate the Pb-related defects on the MHPs surface, thus retarding the charge recombination and promoting the charge transfer efficiency significantly. The amorphous MoSx co-catalyst further promotes the extraction of photogenerated electrons from MHPs and facilitates the HER catalysis. Consequently, drastically enhanced photocatalytic HER activities are obtained on representative MHPs through the synergistic functionalization of PbS and MoSx co-catalysts. A solar-to-chemical (STC) conversion efficiency of ca. 4.63% is achieved on the bi-functionalized FAPbBr3-xIx, which is among the highest values reported for MHPs.
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Abacavir (ABC)-induced hypersensitivity (AHS) is strongly associated with human leukocyte antigen (HLA)-B*57 : 01 expression. Previous studies have demonstrated the feasibility of applying the HLA-transgenic mouse model in this context. ABC-induced adverse reactions were observed in HLA-B*57 : 01 transgenic (B*57 : 01-Tg) mice. Moreover, regulating immune tolerance could result in severe AHS that mimics symptoms observed in the clinical setting, which were modeled in CD4+ T cell-depleted programmed death-1 receptor (PD-1) knockout B*57 : 01-Tg (B*57 : 01-Tg/PD-1-/-) mice. Here, we aimed to examine whether thymus and activation-regulated chemokine (TARC)/CCL17 level can be used as a biomarker for AHS. Serum TARC levels increased in HLA-B*57 : 01-transgenic mice following oral administration of ABC; this increase was associated with the severity of skin toxicity. In ABC-fed CD4+ T cell-depleted B*57 : 01-Tg/PD-1-/- mice, TARC was detected in the epidermal keratinocytes of the ear. Skin toxicity was characterized by the infiltration of CD8+ T cells partially expressing C-C chemokine receptor type 4, which is the primary receptor for TARC. In vivo TARC neutralization effectively alleviated the symptoms of ear skin redness and blood vessel dilatation. Moreover, TARC neutralization suppressed the infiltration of CD8+ T cells to the ear skin but did not affect the ABC-induced adaptive immune response. Therefore, TARC was involved in ABC-induced skin toxicity and contributed to the recruitment of CD8+ T cells to skin. This evidence suggests that serum TARC level may be a functional biomarker for AHS.
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Linfocitos T CD8-positivos , Quimiocina CCL17 , Dermatitis Atópica , Animales , Linfocitos T CD8-positivos/inmunología , Quimiocina CCL17/genética , Quimiocinas , Ciclopropanos/efectos adversos , Didesoxiadenosina/efectos adversos , Didesoxiadenosina/análogos & derivados , Antígenos HLA-B/genética , Humanos , Ratones , Ratones Transgénicos , Receptor de Muerte Celular Programada 1RESUMEN
The involvement between electron transfer (ET) and catalytic reaction at the electrocatalyst surface makes the electrochemical process challenging to understand and control. Even ET process, a primary step, is still ambiguous because it is unclear how the ET process is related to the nanostructured electrocatalyst. Herein, locally enhanced ET current dominated by mass transport effect at corner and edge sites bounded by {111} facets on single Au triangular nanoplates was clearly imaged. After decoupling mass transport effect, the ET rate constant of corner sites was measured to be about 2-fold that of basal {111} plane. Further, we demonstrated that spatial heterogeneity of local inner potential differences of Au nanoplates/solution interfaces plays a key role in the ET process, supported by the linear correlation between the logarithm of rate constants and the potential differences of different sites. These results provide direct images for heterogeneous ET, which helps to understand and control the nanoscopic electrochemical process and electrode design.
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Metal-organic frameworks (MOFs) have been intensively studied as a class of semiconductor-like materials in photocatalysis. However, band bending, which plays a crucial role in semiconductor photocatalysis, has not yet been demonstrated in MOF photocatalysts. Herein, a representative MOF, MIL-125-NH2 , is integrated with the metal oxides (MoO3 and V2 O5 ) that feature appropriate work functions and energy levels to afford the corresponding MOF composites. Surface photovoltage results demonstrate band bending in the MOF composites, which gives rise to the built-in electric field of MIL-125-NH2 , boosting the charge separation. As a result, the MOF composites present 56 and 42â times higher activities, respectively, compared to the pristine MOF for photocatalytic H2 production. Upon depositing Pt onto the MOF, â¼6â times higher activity is achieved. This work illustrates band bending of MOFs for the first time, supporting their semiconductor-like nature, which would greatly promote MOF photocatalysis.
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Plasmon-induced chemical reaction is an emerging field but its development faces huge challenges because of low quantum efficiency. Herein, we report that the solar energy conversion efficiency of Au/TiO2 in plasmon-induced water oxidation is greatly enhanced by intercalating Li+ into TiO2 . An incident photon-to-current efficiency as high as 2.0 %@520â nm is achieved by Au/Li0.2 TiO2 in photoelectrocatalytic water oxidation, realizing a 33-fold enhancement in photocurrent density compared with Au/TiO2 . The superior photoelectrocatalytic performance is mainly ascribed to the enhanced electric conductivity and higher catalytic activity of Li0.2 TiO2 . Furthermore, the ultrafast transient absorption spectroscopy suggests that lithium intercalation into TiO2 could change the dynamics of hot electron relaxation in Au nanoparticles. This work demonstrates that intercalation of alkaline ions into semiconductors can promote the charge separation efficiency of the plasmonic effect of Au/TiO2 .
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Three-dimensional (3D) organic-inorganic hybrid perovskites have demonstrated excellent capability in solar fuel production, while the two-dimensional (2D) counterparts are generally considered inferior candidates due to the high exciton binding energy and weak light absorption. Herein, contrary to our common understanding, we find that 2D perovskites can perform photocatalytic H2 production from HI splitting more efficiently than their 3D counterparts. We observed sharp difference between 2D perovskites crystals with organic phenylalkylammonium cations of different lengths and the 3D counterparts in their stabilization behavior in aqueous solution. Moreover, we show that the organic cations length of the 2D perovskites affects the nanostructures, optoelectronic properties, and the charge transfer process significantly, which determines the photocatalytic activity of the 2D perovskites. Among the 2D perovskites under investigation, phenylmethylammonium lead iodide with the shortest organic cations achieved the best solar-to-chemical conversion efficiency of ca. 1.57 %, which is the highest value ever reported for hybrid perovskites.
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Ferrihydrite (Fh) has been demonstrated as an effective interfacial layer for photoanodes to achieve outstanding photoelectrochemical (PEC) performance for water oxidation reaction owing to its unique hole-storage function. However, it is unknown whether such a hole-storage layer can be used to construct highly efficient photocathodes for hydrogen evolution reaction (HER). In this work, we report Fh interfacial engineering of amorphous silicon photocathode (with nickel as HER cocatalyst) achieving a photocurrent density of 15.6â mA cm-2 at 0â V vs. the reversible hydrogen electrode and a half-cell energy conversion efficiency of 4.08 % in alkaline solution, outperforming most of reported a-Si based photocathodes including multi-junction configurations integrated with noble metal cocatalysts in acid solution. Besides, the photocurrent density is maintained above 14â mA cm-2 for 175â min with 100 % Faradaic efficiency for HER in alkaline solution. Our results demonstrate a feasible approach to construct efficient photocathodes via the application of a hole-storage layer.
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In the plasmonic metal-semiconductor systems, the interfacial structure is vital for both charge separation and photocatalytic reaction. However, the role of interfacial defects, a ubiquitous phenomenon in the metal-semiconductor heterostructure, is not well understood, especially for the hot hole-involved water oxidation reaction. Herein, we studied the effect of interfacial defects, derived from oxygen vacancies, on plasmonic photocatalytic water oxidation. In addition, we found that the plasmon-induced water oxidation activity decreased with the increase in the oxygen vacancies present at the interface, and the activity of Au/TiO2 can be restored after eliminating the defects via a post-oxidation treatment. It is elucidated that a defect state appeared below the conduction band of TiO2 as a result of interfacial defects, which acts as the electron traps and backward transfer channel for electrons to combine with the holes left at the interface. The charge recombination at defect sites leads to the shorter lifetime of hot holes, which is harmful for the kinetics-sluggish water oxidation. This work emphasizes the significance of the interface structure for the plasmon-based photocatalytic process.
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Controlling the interaction of polarization light with an asymmetric nanostructure such as a metal/semiconductor heterostructure provides opportunities for tuning surface plasmon excitation and near-field spatial distribution. However, light polarization effects on interfacial charge transport and the photocatalysis of plasmonic metal/semiconductor photocatalysts are unclear. Herein, we reveal the polarization dependence of plasmonic charge separation and spatial distribution in Au/TiO2 nanoparticles under 45° incident light illumination at the single-particle level using a combination of photon-irradiated Kelvin probe force microscopy (KPFM) and electromagnetic field simulation. We quantitatively uncover the relationship between the local charge density and polarization angle by investigating the polarization-dependent surface photovoltage (SPV). The plasmon-induced photocatalytic activity is enhanced when the polarization direction is perpendicular to the Au/TiO2 interface.
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Photocatalytic overall water splitting has been recognized as a promising approach to convert solar energy into hydrogen. However, most of the photocatalysts suffer from low efficiencies mainly because of poor charge separation. Herein, taking a model semiconductor gallium nitride (GaN) as an example, we uncovered that photogenerated electrons and holes can be spatially separated to the nonpolar and polar surfaces of GaN nanorod arrays, which is presumably ascribed to the different surface band bending induced by the surface polarity. The photogenerated charge separation efficiency of GaN can be enhanced significantly from about 8 % to more than 80 % via co-exposing polar and nonpolar surfaces. Furthermore, spatially assembling reduction and oxidation cocatalysts on the nonpolar and polar surfaces remarkably boosts photocatalytic overall water splitting, with the quantum efficiency increased from 0.9 % for the film photocatalyst to 6.9 % for the nanorod arrays photocatalyst.
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The cocatalysts or dual cocatalysts of photocatalysts are indispensable for high efficiency in artificial photosynthesis for solar fuel production. However, the reaction activity increased by cocatalysts cannot be directly ascribed to the accelerated catalytic kinetics, since photogenerated charges are involved in the elementary steps of photocatalytic reactions. To date, diverging views about cocatalysts show that their exact role for photocatalysis is not well understood yet. Herein, we image directly the local separation of photogenerated charge carriers across single crystals of the BiVO4 photocatalyst which loaded locally with nanoparticles of a MnOx single cocatalyst or with nanoparticles of a spatially separated MnOx and Pt dual cocatalyst. The deposition of the single cocatalyst resulted not only in a strong increase of the interfacial charge transfer but also, surprisingly, in a change of the direction of built-in electric fields beneath the uncovered surface of the photocatalyst. The additive electric fields caused a strong increase of local surface photovoltage signals (up to 80 times) and correlated with the increase of the photocatalytic performance. The local electric fields were further increased (up to 2.5 kV·cm-1) by a synergetic effect of the spatially separated dual cocatalysts. The results reveal that cocatalyst has a conclusive effect on charge separation in photocatalyst particle by aligning the vectors of built-in electric fields in the photocatalyst particle. This effect is beyond its catalytic function in thermal catalysis.
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Plasmonic photocatalysis, stemming from the effective light absorbance and confinement of surface plasmons, provides a pathway to enhance solar energy conversion. Although the plasmonic hot electrons in water reduction have been extensively studied, exactly how the plasmonic hot holes participate in the water splitting reaction has not yet been well understood. In particular, where the plasmonic hot holes participate in water oxidation is still illusive. Herein, taking Au/TiO2 as a plasmonic photocatalyst prototype, we investigated the plasmonic hot holes involved in water oxidation. The reaction sites are positioned by photodeposition together with element mapping by electron microscopy, while the distribution of holes is probed by surface photovoltage imaging with Kelvin probe force microscopy. We demonstrated that the plasmonic holes are mainly concentrated near the gold-semiconductor interface, which is further identified as the reaction site for plasmonic water oxidation. Density functional theory also corroborates these findings by revealing the promotion role of interfacial structure (Ti-O-Au) for oxygen evolution. Furthermore, the interfacial effect on plasmonic water oxidation is validated by other Au-semiconductor photocatalytic systems (Au/SrTiO3, Au/BaTiO3, etc.).
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Elegant Z-scheme WO3/Au/In2S3 nanowire arrays were precisely constructed through a facile step-by-step route. Surface potential change on pristine or In2S3-Au coated WO3 single nanowire under dark and illumination detected through a Kelvin probe force microscopy (KPFM) technique indicates that the vectorial holes transfer of In2S3 â Au â WO3 should occur upon the excitation of both WO3 and In2S3. In such charge transfer processes, the embedded Au nanoparticles in the heterojunction systems act as a charge mediator for electrons in the conduction band of WO3 and holes in the valence band of In2S3. The strong charge carrier separation ability of this structure will finally enhance the oxidation ability of WO3 with high concertation of photogenerated holes and, further, leave the free electrons in the In2S3 with long surviving time. Therefore, the unique Z-scheme WO3/Au/In2S3 heterostructure shows great visible-light activity toward photocatalytic reduction of CO2 in the presence of water vapor into renewable hydrocarbon fuel (methane: CH4).
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Elegant Z-scheme WO3/Au/In2S3 nanowire arrays were precisely constructed through a facile step-by-step route. Surface potential change on pristine or In2S3-Au coated WO3 single nanowire under dark and illumination detected through a Kelvin probe force microscopy (KPFM) technique indicates that the vectorial holes transfer of In2S3 â Au â WO3 should occur upon the excitation of both WO3 and In2S3. In such charge transfer processes, the embedded Au nanoparticles in the heterojunction systems act as a charge mediator for electrons in the conduction band of WO3 and holes in the valence band of In2S3. The strong charge carrier separation ability of this structure will finally enhance the oxidation ability of WO3 with high concertation of photogenerated holes and, further, leave the free electrons in the In2S3 with long surviving time. Therefore, the unique Z-scheme WO3/Au/In2S3 heterostructure shows great visible-light activity toward photocatalytic reduction of CO2 in the presence of water vapor into renewable hydrocarbon fuel (methane: CH4).
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The porous architectures of oxygen cathodes are highly desired for high-capacity lithium-oxygen batteries (LOBs) to support cathodic catalysts and provide accommodation for discharge products. However, controllable porosity is still a challenge for laminated cathodes with cathode materials and binders, since polymer binders usually shield the active sites of catalysts and block the pores of cathodes. In addition, polymer binders such as poly(vinylidene fluoride) (PVDF) are not stable under the nucleophilic attack of intermediate product superoxide radicals in the oxygen electrochemical environment. The parasitic reactions and blocking effect of binders deteriorate and then quickly shut down the operation of LOBs. Herein, the present work proposes a binder-free three-dimensional (3D) porous graphene (PG) cathode for LOBs, which is prepared by the self-assembly and the chemical reduction of GO with triblock copolymer soft templates (Pluronic F127). The interconnected mesoporous architecture of resultant 3D PG cathodes achieved an ultrahigh capacity of 10,300 mAh g-1 for LOBs. Further, the cathodic catalysts ruthenium (Ru) and manganese dioxide (MnO2) were, respectively, loaded onto the inner surface of PG cathodes to lower the polarization and enhance the cycling performance of LOBs. This work provides an effective way to fabricate free-standing 3D porous oxygen cathodes for high-performance LOBs.
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The input of microplastics (MPs) and warming interfere with soil carbon (C) or nitrogen (N) cycles. Although the effects of warming and/or MPs on the cycles have been well studied, the biological coupling of microbial-driven cycles was neglected. Here, the synergistic changes of the cycles were investigated using batch incubation experiments. As results, the influences of MPs were not significant at 15, 20, and 25 °C, and yet, high temperature (i.e., 30 °C) reduced the respiration of high-concentration MPs-amended soil by 9.80%, and increased dissolved organic carbon (DOC) by 14.74%. In contrast, high temperature did not change the effect of MPs on N. The decrease of microbial biomass carbon (MBC) and the constant of microbial biomass nitrogen (MBN) indicated that microbial N utilization was enhanced, which might be attributed to the enrichments of adapted populations, such as Conexibacter, Acidothermus, and Acidibacter. These observations revealed that high temperature and MPs drove the differential response of soil C and N cycles. Additionally, the transcriptomic provided genomic evidence of the response. In summary, the high temperature was a prerequisite for the MPs-driven response, which underscored new ecological risks of MPs under global warming and emphasized the need for carbon emission reduction and better plastic product regulation.
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Microplásticos , Plásticos , Suelo , Carbono , Microbiología del Suelo , Nitrógeno/análisis , Ciclo del NitrógenoRESUMEN
Recent research indicated that ulcers and peripheral vascular disease resulting from drug-resistant bacterial infections are the main causes of delayed healing in chronic diabetic wounds. 5-Aminolevulinic acid (ALA) is a second-generation endogenous photosensitizer. The therapeutic effect and mechanism of ALA-mediated photodynamic therapy (ALA-PDT) on methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds in diabetic rats were investigated in this study. The results revealed the promising antibacterial effects of ALA-PDT MRSA in vitro, with a minimum inhibitory concentration and minimum bactericidal concentration of 250 and 500⯵M, respectively. ALA-PDT also changed the permeability and structural integrity of bacterial cell membranes by producing reactive oxygen species. Meanwhile, ALA-PDT accelerated wound healing in MRSA-infected diabetic rats, with 5â¯% ALA-PDT achieving complete sterilization in 14 days and wound closure in 21 days. Treatment with 5â¯% ALA-PDT additionally improved the histopathological appearance of skin tissue, as well as fibrosis, inflammatory cytokine release, and angiogenesis-related protein expression. These findings indicated that ALA-PDT significantly promoted the healing of MRSA-infected wounds in diabetic rats by eliminating bacteria, inhibiting inflammation, generating granulation tissues, promoting neovascularization, and restoring damaged nerves. In addition, the healing mechanism was related to the activation of inflammatory and angiogenesis pathways through the regulation of tumor necrosis factor-alpha and interleukin-6 expression and upregulation of CD206, CD31, and VEGF. These findings underscored the potential role of ALA-PDT in promoting the healing of chronic diabetic wounds.
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Deep eutectic solvent (DES) is a kind of solvent prepared by mixing hydrogen bond donors and hydrogen bond acceptors, and have become a hot topic in ecological civilization construction due to its low toxicity and sustainability. Its excellent properties such as low volatility, thermal stability and biodegradability make it stand out among many organic solvents and widely used in fields including medicine, chemical industry and agriculture, with broad development prospects. In recent years, the application of DES in the food field has mostly focused on the extraction of small molecular substances, and there are few summaries on the application of DES in macromolecular substances. In this review, we introduced the synthesis, classification and properties of DES, and summarized the application of DES in the food industry for macromolecular substances, including the extraction of macromolecular substances such as chitosan and pectin, as well as the preparation of related macromolecular substrate films. At the same time, we analyzed the characteristics of DES and its advantages and limitations in application, and provided prospects for future development.