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1.
Risk Anal ; 2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38862413

RESUMEN

Investigating the effects of spatial scales on the uncertainty and sensitivity analysis of the social vulnerability index (SoVI) model output is critical, especially for spatial scales finer than the census block group or census block. This study applied the intelligent dasymetric mapping approach to spatially disaggregate the census tract scale SoVI model into a 300-m grids resolution SoVI map in Davidson County, Nashville. Then, uncertainty analysis and variance-based global sensitivity analysis were conducted on two scales of SoVI models: (a) census tract scale; (b) 300-m grids scale. Uncertainty analysis results indicate that the SoVI model has better confidence in identifying places with a higher socially vulnerable status, no matter the spatial scales in which the SoVI is constructed. However, the spatial scale of SoVI does affect the sensitivity analysis results. The sensitivity analysis suggests that for census tract scale SoVI, the indicator transformation and weighting scheme are the two major uncertainty contributors in the SoVI index modeling stages. While for finer spatial scales like the 300-m grid's resolution, the weighting scheme becomes the uttermost dominant uncertainty contributor, absorbing uncertainty contributions from indicator transformation.

2.
Nano Lett ; 23(9): 3963-3970, 2023 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-37102992

RESUMEN

In the templated synthesis of colloidal core-shell nanoparticles, the monomer attachment growth mechanism has been widely accepted to describe the growth process of shells. In this work, by using advanced transmission electron microscope techniques, we directly observe two alternative particle attachment growth pathways that dominate the growth of Au@Ag core-shell nanocuboids. One pathway involves the in situ reduction of AgCl nanoparticles attached to Au nanorods and the subsequent epitaxial growth of the Ag shell. The other pathway involves the adherence of Ag-AgCl Janus nanoparticles to Au nanorods with random orientations, followed by nanoparticle redispersion and the resulting formation of epitaxial Ag shells on the Au nanorods. The particle-mediated growth of Ag shells is accompanied by the redispersion of surface atoms, tending to form a uniform structure. The validation of the particle attachment growth processes at the atomic scale provides a new mechanistic understanding of core-shell nanostructure synthesis.

3.
Nano Lett ; 23(22): 10367-10373, 2023 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-37939002

RESUMEN

The synthesis of highly dispersed Au nanoclusters that are stable under elevated temperatures in heterogeneous catalysis is challenging. Here, we directly observe a strong metal-support interaction (SMSI)-induced dispersion of Au nanoparticles (NPs) on α-MoC using an environmentally atomically resolved secondary imaging technique. Under a realistic environment, Au NPs flatten and spread out on the α-MoC to form two-dimensional atomic layered clusters. The formed highly dispersed Au/α-MoC catalyst shows excellent stability at 600 °C for 160 h in the reverse water-gas shift reaction. The X-ray photoelectron spectrum and extended X-ray absorption fine structure results show that Au NPs gradually become low-coordination-number cluster species and lose electrons to become Auδ+; these form chemical bonds with the α-MoC support and are responsible for the dispersion behavior. This work provides an insightful understanding of dispersion behavior and promotes the rational design and synthesis of reverse sintering catalysts.

4.
J Am Chem Soc ; 145(47): 25834-25841, 2023 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-37967373

RESUMEN

Magnetic nanocatalysts with properties of easy recovery, induced heating, or magnetic levitation play a crucial role in advancing intelligent techniques. Herein, we report a method for the synthesis of versatile core-shell-type magnetic nanocatalysts through "noncontact" hydrogen spillover-driven reduction and migration of iron oxide with the assistance of Pd. In situ analysis techniques were applied to visualize the dynamic evolution of the magnetic nanocatalysts. Pd facilitates the dissociation of hydrogen molecules into activated H*, which then spills and thus drives the iron oxide reduction, gradual outward split, and migration through the carbonaceous shell. By controlling the evolution stage, nanocatalysts having diverse architectures including core-shell, split core-shell, or hollow type, each featuring Pd or PdFe loaded on the carbon shell, can be obtained. As a showcase, a magnetic nanocatalyst (Pd-loaded split core-shell) can hydrogenate crotonaldehyde to butanal (26 624 h-1 in TOF, ∼100% selectivity), outperforming reported Pd-based catalysts. This is due to the synergy of the enhanced local magnetothermal effect and the preferential adsorption of -C═C on Pd with a small d bandwidth. Another catalyst (PdFe-loaded split core-shell) also delivers a robust performance in phenylacetylene semihydrogenation (100% conversion, 97.5% selectivity) as PdFe may inhibit the overhydrogenation of -C═C. Importantly, not only Pd, other noble metals (e.g., Pt, Ru, and Au) also showed a similar property, revealing a general rule that hydrogen spillover drives the dynamic reduction, splitting, and migration of encapsulated nanosized iron oxide, resulting in diverse structures. This study would offer a structure-controllable fabrication of high-performance magnetic nanocatalysts for various applications.

5.
Artículo en Inglés | MEDLINE | ID: mdl-37185274

RESUMEN

A Gram-stain-negative marine bacterium, designated as WX04T, was isolated from the South China Sea. The genome of strain WX04T contained a complete photosynthetic gene cluster and is the first identified photoheterotroph of the genus Shimia with high photochemical efficiency (Fv/Fm=0.705±0.010), indicating its diverse metabolic and growth strategies, and unique evolution in the genus Shimia. The genome size of strain WX04T is 3.78 Mbp, and the G+C content is 58.8 %. Its isolate formed pink colonies and the cells were non-flagellated and rod-shaped. Growth was observed at 15-35 °C (optimum, 30 °C), at pH 5.0-11.0 (optimum, pH 7.0) and in the presence of 3-5 % (w/v) NaCl (optimum, 3 %). Both catalase activity and oxidase activity were found to be negative. The 16S rRNA gene sequence analyses revealed that this isolate represents a novel species within the genus Shimia, sharing 96.8 and 95.6% sequence identities with Shimia aestuarii DSM 15283T and Shimia marina DSM 26895T, respectively. The respiratory quinone was ubiquinone-10 (100 %). The primary cellular fatty acids (>5 %) were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C18 : 0,C18 : 1 ω7c 11-methyl and C10 : 0 3-OH. The dominant polar lipids of strain WX04T comprised phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol. The combined polyphasic data shows that strain WX04T is a novel species within the genus Shimia, which is proposed as Shimia ponticola sp. nov., and the type strain is WX04T (=KCTC 62628T=MCCC 1K02295T).


Asunto(s)
Ácidos Grasos , Agua de Mar , Ácidos Grasos/química , ARN Ribosómico 16S/genética , Composición de Base , Análisis de Secuencia de ADN , Hibridación de Ácido Nucleico , Filogenia , Técnicas de Tipificación Bacteriana , ADN Bacteriano/genética , Agua de Mar/microbiología , Fosfolípidos/química
6.
J Fluoresc ; 2023 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-37713014

RESUMEN

In this study, a dual-mode ratiometric fluorometric and colorimetric platform for the determination of nitrite in pickles was proposed by exquisitely employing the fact that non-fluorescent o-Phenylenediamine (OPD) was oxidized by nitrite under acidic conditions to form fluorescent 2,3-diaminophenazine (DAP) (Em = 575), which meanwhile quench the fluorescent nitrogen-doped carbon dots (N-CDs) at 455 nm, the ratio of fluorescence intensity of DAP to N-CDs (F575/F455) changed with the increase of nitrite accompanied by visible color changes. Thus, nitrite can be quantitatively detected within a wide linear range (10-500 µM) with a low detection limit of 0.45 µM due to the high quantum yield of 39.7% of N-CDs. In addition, the colour of the N-CDs/OPD system changed from transparent to yellow when the nitrite was introduced, enabling colorimetric and on-site visual detection. The detection limit of the colorimetric method was 3.03 µM with a linear range of 10-500 µM. The proposed ratiometric fluorometric method has pleasant selectivity and good immunity to interference.

7.
Angew Chem Int Ed Engl ; 62(50): e202313172, 2023 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-37908153

RESUMEN

Cooperative coupling of H2 evolution with oxidative organic synthesis is promising in avoiding the use of sacrificial agents and producing hydrogen energy with value-added chemicals simultaneously. Nonetheless, the photocatalytic activity is obstructed by sluggish electron-hole separation and limited redox potentials. Herein, Ni-doped Zn0.2 Cd0.8 S quantum dots are chosen after screening by DFT simulation to couple with TiO2 microspheres, forming a step-scheme heterojunction. The Ni-doped configuration tunes the highly active S site for augmented H2 evolution, and the interfacial Ni-O bonds provide fast channels at the atomic level to lower the energy barrier for charge transfer. Also, DFT calculations reveal an enhanced built-in electric field in the heterojunction for superior charge migration and separation. Kinetic analysis by femtosecond transient absorption spectra demonstrates that expedited charge migration with electrons first transfer to Ni2+ and then to S sites. Therefore, the designed catalyst delivers drastically elevated H2 yield (4.55 mmol g-1 h-1 ) and N-benzylidenebenzylamine production rate (3.35 mmol g-1 h-1 ). This work provides atomic-scale insights into the coordinated modulation of active sites and built-in electric fields in step-scheme heterojunction for ameliorative photocatalytic performance.

8.
J Am Chem Soc ; 144(27): 12410-12420, 2022 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-35758858

RESUMEN

Tailoring the morphology of nanocrystals is a promising way to enhance their catalytic performance. In most previous shape-controlled synthesis strategies, surfactants are inevitable due to their capability to stabilize different facets. However, the adsorbed surfactants block the intrinsic active sites of the nanocrystals, reducing their catalytic performance. For now, strategies to control the morphology without surfactants are still limited but necessary. Herein, a facile surfactant-free synthesis method is developed to regulate the morphology of Cu2O nanocrystals (e.g., solid nanocube, concave nanocube, cubic framework, branching nanocube, branching concave nanocube, and branching cubic framework) to enhance the electrocatalytic performance for the conversion of CO to n-propanol. Specifically, the Cu2O branching cubic framework (BCF-Cu2O), which is difficult to fabricate using previous surfactant-free methods, is fabricated by combining the concentration depletion effect and the oxidation etching process. More significantly, the BCF-Cu2O-derived catalyst (BCF) presents the highest n-propanol current density (-0.85 mA cm-2) at -0.45 V versus the reversible hydrogen electrode (VRHE), which is fivefold higher than that of the surfactant-coated Cu2O nanocube-derived catalyst (SFC, -0.17 mA cm-2). In terms of the n-propanol Faradaic efficiency in CO electroreduction, that of the BCF exhibits a 41% increase at -0.45 VRHE as compared with SFC. The high catalytic activity of the BCF that results from the clean surface and the coexistence of Cu(100) and Cu(110) in the lattice is well-supported by density functional theory calculations. Thus, this work presents an important paradigm for the facile fabrication of surface-clean nanocrystals with an enhanced application performance.

9.
J Am Chem Soc ; 144(45): 20964-20974, 2022 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-36283036

RESUMEN

Precise synthesis of well-ordered ultrathin nanowire arrays with tunable active surface, though attractive in optoelectronics, remains challenging to date. Herein, well-aligned sub-10 nm TiO2 nanowire arrays with controllable corrugated structure have been synthesized by a unique monomicelle-directed assembly method. The nanowires with an exceptionally small diameter of ∼8 nm abreast grow with an identical adjacent distance of ∼10 nm, forming vertically aligned arrays (∼800 nm thickness) with a large surface area of ∼102 m2 g-1. The corrugated structure consists of bowl-like concave structures (∼5 nm diameter) that are closely arranged along the axis of the ultrathin nanowires. And the diameter of the concave structures can be finely manipulated from ∼2 to 5 nm by simply varying the reaction time. The arrays exhibit excellent charge dynamic properties, leading to a high applied bias photon-to-current efficiency up to 1.4% even at a very low potential of 0.41 VRHE and a superior photocurrent of 1.96 mA cm-2 at 1.23 VRHE. Notably, an underlying mechanism of the hole extraction effect for concave walls is first clarified, demonstrating the exact role of concave walls as the hole collection centers for efficient water splitting.

10.
Chemistry ; 26(18): 4052-4062, 2020 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-31437320

RESUMEN

Using bimetallic Prussian blue analogue (PBA) as a precursor is effective for preparing electrocatalysts for the oxygen evolution reaction (OER); however, the role of these PBA-derived catalysts in the OER is still ambiguous. Herein, by simply controlling synthesis temperature, a bimetallic PBA-derived O,N-codoped Ni-Fe carbide, can be well tuned to optimize structure and OER performance. Importantly, by a series of ex situ and in situ investigations, real active species of NiFeOx Hy are in situ formed on the surface during the OER, which reveals a "pre-catalyst" role of O,N-codoped Ni-Fe carbides. Furthermore, it has been successfully applied to highly efficient Zn-air batteries and outplays its RuO2 counterpart. When applied to photoelectrocatalytic water oxidation as the co-catalyst, it improves the performance of the BiVO4 photoanode by enhancing hole collecting and transporting ability. We believe this research not only provides a highly efficient and low-cost electrocatalyst for the OER, but also unveils the "pre-catalyst" role of PBA-derived materials in energy-storage and conversion devices.

11.
Angew Chem Int Ed Engl ; 59(49): 22246-22251, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-32815276

RESUMEN

In photocatalysis, the Schottky barrier in metal-semiconductor hybrids is known to promote charge separation, but a core-shell structure always leads to a charge build-up and eventually shuts off the photocurrent. Here, we show that Au-Cu2 O hybrid nanostructures can be continuously tuned, particularly when the Cu2 O domains are single-crystalline. This is in contrast to the conventional systems, where the hybrid configuration is mainly determined by the choice of materials. The distal separation of the Au-Cu2 O domains in Janus nanostructures leads to enhanced charge separation and a large improvement of the photocurrent. The activity of the Au-Cu2 O Janus structures is 5 times higher than that of the core-shell structure, and 10 times higher than that of the neat Cu2 O nanocubes. The continuous structural tuning allows to study the structure-property relationship and an optimization of the photocatalytic performance.

12.
BMC Med Educ ; 19(1): 234, 2019 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-31242945

RESUMEN

BACKGROUND: Although the inclusion of arts in medical school curricula has garnered attention, little is known about the effect of arts-based interventions on the behaviors, attitudes, and technical skills of students. The Art of Observation is an optional elective at the University of Texas Southwestern Medical Center (UTSW) in collaboration with educators from the Dallas Museum of Art (DMA). We utilized a qualitative approach to describe in-depth how engaging with art influences the development of medical students' observation skills and empathy. METHODS: We analyzed evaluations from 65 medical students who completed the course between 2015 and 2017. Evaluations contained open-ended questions that asked students to reflect upon their experiences and describe their perceptions, thoughts, and feelings after guided museum visits. We used grounded theory to generate a thematic codebook, then employed axial coding to discover thematic relationships. RESULTS: We report three main findings and several subthemes: (1) Enhanced observation skills: by engaging with art and completing relevant activities, students developed the ability to synthesize a compelling narrative in addition to learning technical skills; (2) Improved physician socialization: students reported enhanced self-awareness, increased tolerance of ambiguity, and development of a humanistic view of medicine, key components of physician socialization; and (3) Reduction in burnout symptoms: students reported an enhanced sense of well-being after each session, which mitigates the process of burnout. CONCLUSIONS: Fine arts can be used to teach technical skills, stimulate personal reflection, and prevent burnout. A meaningful engagement with the arts can play an important role in developing physicians who are observant, empathetic, and more well-rounded.


Asunto(s)
Arte , Curriculum , Educación de Pregrado en Medicina , Agotamiento Profesional/prevención & control , Empatía , Teoría Fundamentada , Humanos , Relaciones Interpersonales , Narración , Observación , Facultades de Medicina , Estudiantes de Medicina/psicología , Texas
14.
Research (Wash D C) ; 6: 0043, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36930759

RESUMEN

Chemical electron microscopy (CEM), a toolbox that comprises imaging and spectroscopy techniques, provides dynamic morphological, structural, chemical, and electronic information about an object in chemical environment under conditions of observable performance. CEM has experienced a revolutionary improvement in the past years and is becoming an effective characterization method for revealing the mechanism of chemical reactions, such as catalysis. Here, we mainly address the concept of CEM for heterogeneous catalysis in the gas phase and what CEM could uniquely contribute to catalysis, and illustrate what we can know better with CEM and the challenges and future development of CEM.

15.
Materials (Basel) ; 16(19)2023 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-37834531

RESUMEN

Aeolian sand (AS) and recycled coarse aggregate (RCA) can be reasonably utilized as green materials for concrete modification. The paucity of natural sand and gravel in the construction industry is anticipated to be remedied by the use of these two eco-friendly concrete ingredients. This is incredibly important for environmental protection. Study on the damage law of self-compacting concrete with the addition of AS and RCA (ARSCC) under severely cold conditions is of great significance for the promotion and implementation of this material. In this study, 12 groups of ARSCC specimens were prepared for freeze-thaw cycle experiments, with AS substitution rates of 0, 20%, 40%, and 60% as well as RCA replacement rates of 0, 25%, and 50%. Then, the degradation mechanism of ARSCC freeze-thaw damage was discussed from both macroscopic and microscopic perspectives via mass loss rate (Wn), relative dynamic modulus of elasticity (Pn), bubble spacing factor, and SEM analysis. Finally, the response surface method was utilized to determine the damage variable. A freeze-thaw damage model for ARSCC was developed based on the Weibull distribution and Grey theories. The results showed that the Pn could reflect the evolution law of the internal structure of ARSCC. Appropriate addition of AS to fill the large, harmful pores in RCA would inhibit freeze-thaw damage of ARSCC. The optimum substitution rates of AS and RCA were determined to be 20-40% and 25-50%, respectively. In addition, the values obtained from theoretical damage modeling and experiments were in good agreement. The acquired damage model had the potential to predict ARSCC damage under freeze-thaw cycles.

16.
J Agric Food Chem ; 71(33): 12587-12596, 2023 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-37561819

RESUMEN

Gallic acid (GA, 3,4,5-trihydroxybenzoic acid) is a widely used natural food additive of interest to food chemistry researchers, especially regarding its effects on myofibrillar protein (MP) oxidation. However, existing studies regarding MP oxidation by GA-combined with Fenton reagents are inconsistent, and the detailed mechanisms have not been fully elucidated. This work validated hydroxyl radical (HO·) as the primary oxidant for MP carbonylation; in addition, it revealed three functions of GA in the Fenton oxidation of MP. By coordination with Fe(III), GA reduces Fe(III) to generate Fe(II), which is the critical reagent for HO· generation; meanwhile, the coordination improves the availability and reactivity of Fe(III) under weakly acidic and near-neutral pH, i.e., pH 4-6. Second, the intermediates formed during GA oxidation, including semiquinone and quinone, promoted Fenton reactivity by accelerating Fe catalytic cycling. Finally, GA can scavenge HO· radicals, thus exhibiting a certain degree of antioxidant property. All three functions contribute to MP oxidation as observed in GA-containing meat.


Asunto(s)
Compuestos Férricos , Ácido Gálico , Ácido Gálico/química , Compuestos Férricos/química , Oxidación-Reducción , Antioxidantes/metabolismo , Peróxido de Hidrógeno/química , Radical Hidroxilo
17.
Heliyon ; 9(6): e16722, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37303521

RESUMEN

Background: Ossification of ligamentum flavum (OLF) is a hidden, indolent disease condition with variable unexplained etiology and pathology. Growing evidences show a correlation between senile osteoporosis (SOP) and OLF, but the fundamental relationship between SOP and OLF remains unclear. Therefore, the purpose of this work is to investigate unique SOP-related genes and their potential functions in OLF. Methods: Gene Expression Omnibus (GEO) database was utilized to gather the mRNA expression data (GSE106253) and then analyzed by R software. A variety of methods, including ssGSEA, machine learning (LASSO and SVM-RFE), GO and KEGG enrichment, PPI network, transcription factor enrichment analysis (TFEA), GSEA and xCells were employed to verified the critical genes and signaling pathways. Furthermore, ligamentum flavum cells were cultured and used in vitro to identify the expression of the core genes. Results: The preliminary identification of 236 SODEGs revealed their involvement in BP pathways associated with ossification, inflammation, and immune response, including the TNF signaling pathway, PI3K/AKT signaling pathway and osteoclast differentiation. Four down-regulated genes (SERPINE1, SOCS3, AKT1, CCL2) and one up-regulated gene (IFNB1) were among the five hub SODEGs that were validated. Additionally, they were performed by ssGSEA and xCell to show the relationship of immune cells infiltrating in OLF. The most fundamental gene, IFNB1, which was only found in the classical ossification- and inflammation-related pathways, suggested that it may affect OLF via regulating the inflammatory response. In vitro experiment, we found that IFNB1 expression was dramatically higher in cells cocultured with osteogenic induction than in controls. Conclusion: As far as we are concerned, this is the first observation using transcriptome data mining to reveal distinct SOP-related gene profiles between OLF and normal controls. Five hub SODEGs were ultimately found using bioinformatics algorithms and experimental verification. These genes may mediate intricate inflammatory/immune responses or signaling pathways in the pathogenesis of OLF, according to the thorough functional annotations. Since IFNB1 was discovered to be a key gene and was connected to numerous immune infiltrates in OLF, it is possible that IFNB1 expression has a substantial impact on the pathogenesis of OLF. Our research will give rise to new possibilities for potential therapeutics that target SOP reverent genes and immune-associated pathways in OLF.

18.
Adv Mater ; 35(31): e2302793, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37208970

RESUMEN

Catalysts with designable intelligent nanostructure may potentially drive the changes in chemical reaction techniques. Herein, a multi-function integrating nanocatalyst, Pt-containing magnetic yolk-shell carbonaceous structure, having catalysis function, microenvironment heating, thermal insulation, and elevated pressure into a whole is designed, which induces selective hydrogenation within heating-constrained nanoreactors surrounded by ambient environment. As a demonstration, carbonyl of α, ß-unsaturated aldehydes/ketones are selectively hydrogenated to unsaturated alcohols with a >98% selectivity at a nearly complete conversion under mild conditions of 40 °C and 3 bar instead of harsh requirements of 120 °C and 30 bar. It is creatively demonstrated that the locally increased temperature and endogenous pressure (estimated as ≈120 °C, 9.7 bar) in the nano-sized space greatly facilitate the reaction kinetics under an alternating magnetic field. The outward-diffused products to the "cool environment" remain thermodynamically stable, avoiding the over-hydrogenation that often occurs under constantly heated conditions of 120 °C. Regulation of the electronic state of Pt by sulfur doping of carbon allows selective chemical adsorption of the CO group and consequently leads to selective hydrogenation. It is expected that such a multi-function integrated catalyst provides an ideal platform for precisely operating a variety of organic liquid-phase transformations under mild reaction conditions.

19.
Adv Mater ; 34(38): e2203225, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35944441

RESUMEN

Cooperative coupling of photocatalytic H2 O2 production with organic synthesis has an expansive perspective in converting solar energy into storable chemical energy. However, traditional powder photocatalysts suffer from severe agglomeration, limited light absorption, poor gas reactant accessibility, and reusable difficulty, which greatly hinders their large-scale application. Herein, floatable composite photocatalysts are synthesized by immobilizing hydrophobic TiO2 and Bi2 O3 on lightweight polystyrene (PS) spheres via hydrothermal and photodeposition methods. The floatable photocatalysts are not only solar transparent, but also upgrade the contact between reactants and photocatalysts. Thus, the floatable step-scheme (S-scheme) TiO2 /Bi2 O3 photocatalyst exhibits a drastically enhanced H2 O2 yield of 1.15 mm h-1 and decent furfuryl alcohol conversion to furoic acid synchronously. Furthermore, the S-scheme mechanism and dynamics are systematically investigated by in situ irradiated X-ray photoelectron spectroscopy and femtosecond transient absorption spectrum analyses. In situ Fourier transform infrared spectroscopy and density functional theory calculations reveal the mechanism of furoic acid evolution. The ingenious design of floatable photocatalysts not only furnishes insight into maximizing photocatalytic reaction kinetics but also provides a new route for highly efficient heterogeneous catalysis.

20.
RSC Adv ; 12(31): 19869-19874, 2022 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-35865192

RESUMEN

High-entropy alloys (HEAs) with multiple elements in near-equiatomic proportions hold great promise in heterogeneous catalysis because of their exceptional physicochemical properties governed by synergy. Herein, we prepared PtPdCoCuNi HEA nanoparticles via a one-step colloid-based route and tested their catalytic performance for nitrobenzene hydrogenation to aniline. The SiO2 supported PtPdCoCuNi displays 93.9% yield of aniline at 80 °C, which is 2.11 times that of PtPd/SiO2. Even at room temperature, a 47.4% yield of aniline is attained with the PtPdCoCuNi/SiO2 catalyst. DRIFTS experiments indicate formation of isolated Pt and Pd sites after alloying the transition metals and evidence a stronger interaction between the HEA catalyst and nitrobenzene. Both XPS data and DFT calculations disclose charge transfer to Pt and Pd species, which eventually enhance the interaction between nitrobenzene and the isolated metal sites and the hydrogenation activity as well. The experimental and theoretical results shed light on mechanistic understanding of the unique catalytic performance of the HEA nanocatalyst and pave a new avenue to realize the high catalytic performance of nitrobenzene hydrogenation over well-isolated noble metal sites with specific geometries.

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