Neel Sisodia  Monica Miranda  Kay L. McGuinness  Jay D. Wadhawan  Nathan S. Lawrence 《Electroanalysis》2021,33(3):559-562

This work presents the electrochemical response of a 2-(methylthio)phenol glassy carbon based electrode for a promising voltammetric pH sensor in both buffered and low-buffered solutions. Electropolymerization of the redox species was performed with the resulting polymer presenting a Nernstian response in buffered media, with a sensitivity of 51 mV/pH unit. The effectiveness of the sulfhydryl bond to facilitate proton transfer from the bulk solution to the phenol molecules has been confirmed, providing an accurate pH measurement of 8.28 in sea water media, compared to that measured with a calibrated glass pH probe of 8.30.  相似文献   

    

Christine Curiac  Roberta R. Rodrigues  Jonathon Watson  Leigh Anna Hunt  Anthony Devdass  Prof. Jonah W. Jurss  Prof. Nathan I. Hammer  Prof. Ryan C. Fortenberry  Prof. Jared H. Delcamp 《ChemSusChem》2021,14(15):3084-3096

A series of iron polypyridyl redox shuttles were synthesized in the 2+ and 3+ oxidation states and paired with a series of wide optical gap organic dyes with weak aryl ether electron-donating groups. High voltage dye-sensitized solar cell (HV-DSC) devices were obtained through controlling the redox shuttle energetics and dye donor structure. The use of aryl ether donor groups, in place of commonly used aryl amines, allowed for the lowering of the dye ground-state oxidation potential which enabled challenging to oxidize redox shuttles based on Fe²⁺ polypyridyl structures to be used in functional devices. By carefully designing a dye series that varies the number of alkyl chains for TiO₂ surface protection, the recombination of electrons in TiO₂ to the oxidized redox shuttle could be controlled, leading to HV-DSC devices of up to 1.4 V.  相似文献   

    

Arun S. Asundi  Dr. Adam S. Hoffman  Sindhu S. Nathan  Dr. Alexey Boubnov  Dr. Simon R. Bare  Dr. Stacey F. Bent 《ChemCatChem》2021,13(4):1186-1194

The design of supported heterogeneous catalysts requires a detailed understanding of the structure and chemistry of the active surface. Although the chemical components of the active phase, support material, and process feed are typically considered to be the most important factors governing catalyst structure and performance, many common commercial supports contain trace impurities, which can have profound effects on catalyst properties. In this work, we study silica-supported cobalt-based catalysts, which are widely used in syngas conversion to value-added products. Supported metallic Co is a commercial Fischer-Tropsch catalyst, whereas Co₂C has shown promise for the direct conversion of syngas to higher oxygenates. This study examines the effects of Na, a commonly detected support impurity and a frequently used promoter, on the structure and reactivity of Co and Co₂C. We show that trace Na impurities significantly decrease catalyst activity of supported metallic Co, and that high Na concentrations result in Co₂C formation and a loss in Fischer-Tropsch activity. However, in Co₂C catalysts, Na plays an important role in stabilizing the Co₂C phase, but excess Na decreases catalyst activity. We use in situ X-ray absorption spectroscopy to study Co₂C formation and decomposition in the Na-free catalyst under carburization and reaction conditions. The work reveals the importance of carefully controlling alkali metal content, particularly at trace levels, in catalyst design.  相似文献   

    

Kui Wu  Nathan A. Yee  Sangeetha Srinivasan  Amir Mahmoodi  Michael Zakharian  Jose M. Mejia Oneto  Maksim Royzen 《Chemical science》2021,12(21):7583

Correction for ‘Click activated protodrugs against cancer increase the therapeutic potential of chemotherapy through local capture and activation’ by Kui Wu et al., Chem. Sci., 2021, 12, 1259–1271, DOI: 10.1039/D0SC06099B.

The authors regret that the reference to the bond-breaking bioorthogonal chemistry, termed ‘click-to-release’ was omitted from the original article. In addition, we would like to include a reference describing the synthesis of compound 1, which is an intermediate to the protodrugs described in the original article. These references are listed below as ref. 1 and 2.The Royal Society of Chemistry apologizes for these errors and any consequent inconvenience to authors and readers.  相似文献   

    

Nathan Corbin  Deng-Tao Yang  Nikifar Lazouski  Katherine Steinberg  Karthish Manthiram 《Chemical science》2021,12(37):12365

Although electrocarboxylation reactions use CO₂ as a renewable synthon and can incorporate renewable electricity as a driving force, the overall sustainability and practicality of this process is limited by the use of sacrificial anodes such as magnesium and aluminum. Replacing these anodes for the carboxylation of organic halides is not trivial because the cations produced from their oxidation inhibit a variety of undesired nucleophilic reactions that form esters, carbonates, and alcohols. Herein, a strategy to maintain selectivity without a sacrificial anode is developed by adding a salt with an inorganic cation that blocks nucleophilic reactions. Using anhydrous MgBr₂ as a low-cost, soluble source of Mg²⁺ cations, carboxylation of a variety of aliphatic, benzylic, and aromatic halides was achieved with moderate to good (34–78%) yields without a sacrificial anode. Moreover, the yields from the sacrificial-anode-free process were often comparable or better than those from a traditional sacrificial-anode process. Examining a wide variety of substrates shows a correlation between known nucleophilic susceptibilities of carbon–halide bonds and selectivity loss in the absence of a Mg²⁺ source. The carboxylate anion product was also discovered to mitigate cathodic passivation by insoluble carbonates produced as byproducts from concomitant CO₂ reduction to CO, although this protection can eventually become insufficient when sacrificial anodes are used. These results are a key step toward sustainable and practical carboxylation by providing an electrolyte design guideline to obviate the need for sacrificial anodes.

Selective electrocarboxylation of nucleophilically susceptible organic halides without sacrificial anodes is enabled by inorganic salt additives, which suppress the nucleophilicity of anions in the electrolyte.  相似文献   

    

Nathan Corbin  Deng-Tao Yang  Nikifar Lazouski  Katherine Steinberg  Karthish Manthiram 《Chemical science》2021,12(38):12847

Correction for ‘Suppressing carboxylate nucleophilicity with inorganic salts enables selective electrocarboxylation without sacrificial anodes’ by Nathan Corbin et al., Chem. Sci., 2021, DOI: 10.1039/D1SC02413B.

We regret that there was a minor error in the structure of the benzyl chloride in Scheme 2, Fig. 2 and the ESI. The structure of the benzyl chloride should be 4-methyl benzyl chloride but was instead given as 3-methyl benzyl. The correct figure and scheme are shown below, and the ESI has been updated.Open in a separate windowFig. 2(A) Comparison of acid yields for non-sacrificial-anode and sacrificial-anode carboxylation of various substrates. (B) Ratio of carboxylic acid to nucleophilic side products (ester + carbonate + alcohol) for various systems and substrates. Effect of adding MgBr₂ to the sacrificial-anode system on the (C) acid yield and (D) ratio of acid to S_N2 side products for benzyl bromide. Acid yields are tabulated in Table S6.† ND: acid not detected (acid-to-S_N2 ratio <0.1).Open in a separate windowScheme 2Substrate scope for the sacrificial-anode-free electrochemical carboxylation of organic halides. ^aStandard reaction conditions: 100 mM electrolyte, 100 mM substrate, 100 mM MgBr₂, silver cathode, platinum anode, 20 sccm CO₂, 2.2 mL DMF, −20 mA cm⁻² for 3.5 h. TBA-Br was used for chlorinated substrates because bromide oxidizes more readily than chloride, and only a small amount of chloride was replaced by bromide (<1% for the alkyl chloride, ∼4% for the benzylic chloride). Yields are referenced to the initial amount of substrate and were calculated from ¹H NMR spectroscopy using either 1,3,5-trimethoxybenzene or ethylene carbonate as internal standards. ^b−15 mA cm⁻² instead of −20 mA cm⁻². ^c150 mM MgBr₂ instead of 100 mM MgBr₂.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.  相似文献   

    

Fabrizio R. Giorgetta  Jeff Peischl  Daniel I. Herman  Gabriel Ycas  Ian Coddington  Nathan R. Newbury  Kevin C. Cossel 《Laser u0026amp; Photonics Reviews》2021,15(9):2000583

Open-path dual-comb spectroscopy provides multispecies atmospheric gas concentration measurements with high precision. Here, open-path dual-comb spectroscopy is extended to the mid-infrared 5 µm atmospheric window, enabling atmospheric concentration retrievals of the primary greenhouse gases, N₂O, CO₂, and H₂O, as well as the criteria air pollutants O₃ and CO across 600 m and 2 km round-trip paths. Measurements are demonstrated over a five-day period at 2 min temporal resolution with 80% uptime. The achieved precision is sufficient to resolve the atmospheric concentration variations of the multiple gas species; retrieved dry mixing ratios of CO and N₂O are in good agreement with a colocated point sensor. In addition, the retrieved ratio of excess CO versus CO₂ agrees with similar urban studies but disagrees with the US National Emission Inventory by a factor of 3. The retrieved ratio of excess N₂O versus CO₂ exhibits a plume-dependent value, indicating the variability of sources of the greenhouse gas N₂O.  相似文献   

    

Nathan Cassidy  Paul Blenkinsopp  Ian Brown  Richard J. Curry  B. N. Murdin  Roger Webb  David Cox 《physica status solidi (a)》2021,218(1)

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Nathan D. Cottam  Chengxi Zhang  Joni L. Wildman  Amalia Patanè  Lyudmila Turyanska  Oleg Makarovsky 《Advanced Optical Materials》2021,9(13):2100104

Inorganic perovskite nanocrystals (NCs) have demonstrated a number of unique optical and electronic properties for optoelectronic applications. However, the physical properties of these nanostructures, such as the dynamics of charge carriers on different timescales and their effect on the optical recombination of carriers, are not yet fully understood. This work reports on a slow (>1 s) reversible quenching of the NC photoluminescence due to a light-induced Stark effect involving defects on the surface of the NCs and the redistribution of photoexcited carriers onto the NC surface. This phenomenon can influence the operation of optoelectronic devices based on these NCs, including hybrid photosensors based on graphene decorated with inorganic perovskite NCs, revealing their prospects and limitations.  相似文献   

    

Mustapha A. A. Jebar  Nathan J. Downs  Alfio V. Parisi  Joanna Turner 《Photochemistry and photobiology》2021,97(1):192-197

This research presents a novel methodology for deriving the total daily broadband solar UVA (320–400 nm) received by school teachers during their working day from Ozone Monitoring Instrument (OMI) satellite solar noon UVA irradiance measurements for a Queensland subtropical site (27.5°S, 152°E). Daily UVA exposures are weighted to the anatomical human cheek (anterior infra‐orbital region) for teachers wearing and not wearing broad‐brimmed hats. The method utilizes the OMI UVA irradiance data collected daily at high temporal resolution over 2005 to 2016 to derive the total daily UVA exposure to a horizontal plane. These horizontal plane exposures are scaled by factors to take into account the timing of outdoor activity. The relationship between exposures to a horizontal plane and those to a vertical plane and the protection provided by a broad‐brimmed hat was assessed to evaluate the total daily UVA exposures to the cheek for classroom and physical education teaching staff expected to be outside at different periods of the day. The developed method enables the total daily UVA exposure to specific anatomical sites to be evaluated from the satellite solar noon irradiance at locations that do not have access to surface‐based instrumentation capable of recording in the solar UVA waveband.  相似文献