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Surface-enhanced infrared absorption spectroscopy (SEIRAS) was employed to investigate the structure of the interfacial water in the 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC)/valinomycin floating bilayer on the gold surface in two electrolytes with different cations, KClO4 and NaClO4. The SEIRAS studies indicate that interfacial water adopts different structures in the bilayer with different cations. The structure of interfacial water in the DPhPC/valinomycin bilayer in the NaClO4 solution is similar to water in the DPhPC bilayer (without valinomycin), while the structure of water in the bilayer in the KClO4 solution has a high amount of disordered hydrogen bond network. The results of the present study confirm that valinomycin selectively transports K+ across the lipid bilayer as an ion pair and that the ion pair is bonded to residual water that is released into the submembrane region. [ABSTRACT FROM AUTHOR]

Graphene oxide-based nanomaterials are garnering significant attention from various fields due to their unique physical and chemical properties, which make them attractive for myriad applications. This feature article stems from Dr. Aicheng Chen's Lecture for the 2023 Ricardo Aroca Award of the Canadian Society for Chemistry and focuses primarily on the synthesis and applications of graphene oxide-based nanomaterials for electrochemical sensing. Graphene oxide (GO), reduced graphene oxide, and functionalized and doped GO-based nanomaterials are emerging as promising enablers of broad applications in electrochemical sensors. This is due to their distinctive functional groups and novel properties, which include high electrical conductivities, large surface areas, and enhanced catalytic activities. Several strategies for the synthesis of these nanomaterials are described in this feature article, encompassing the modified Hummers method, electrochemical, thermal, and microwave reactor methods. The characterization of these GO-based nanomaterials is highlighted, employing techniques such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Raman, and X-ray photoelectron spectroscopy to study their morphologies, structures, and chemical compositions. The development of GO-based electrochemical sensors and their pharmaceutical, medical, environmental, and food safety applications are discussed. Further, the effects of these GO-based nanomaterials and different electrochemical techniques (e.g., cyclic voltammetry, square wave voltammetry, linear sweep voltammetry, and differential pulse voltammetry) on the performance of various electrochemical sensors are addressed. [ABSTRACT FROM AUTHOR]

Carbon capture and utilization (CCU) are technologies sought to reduce the level of CO2 in the atmosphere. Industrial carbon capture is associated with energetic penalty, thus there is an opportunity to research alternatives. In this work, spectroelectrochemistry was used to analyze the electrochemical CO2 reduction (eCO2R) in CO2 saturated monoethanolamine (MEA)‐based capture solutions, in a novel CCU process. The in situ Fourier transform infrared (FTIR) spectroscopy experiments show that at the Bi catalyst, the active species involved in the eCO2R is the dissolved CO2 in solution, and not carbamate. In addition, the products of eCO2R were evaluated under flow, using commercial Bi2O3 NP as catalyst. Formate and acetate were detected, with normalized FE for acetate up to 14.5 %, a remarkable result, considering the catalyst used. Acetate is formed either in the presence of cetrimonium bromide (CTAB) as surfactant or at higher current density (>−100 mA cm−2) and the results enabled the proposition of a pathway for its production. This work sheds light on the complex reaction environment of a capture medium electrolyte and is thus relevant for an improved understanding of the conversion of CO2 into value‐added products and to evaluate the feasibility of a combined CCU approach. [ABSTRACT FROM AUTHOR]

Cardiovascular disease is one of the leading causes of premature death worldwide, and the determination of C-reactive protein (CRP) from human serum is of vital importance for the diagnosis of the disease. For this study, we have developed an electrochemical immunosensor based on onion-like carbon@polyacrylonitrile (OLC-PAN) for the detection of CRP antigens. This was accomplished by immobilizing CRP antibodies on a modified glassy carbon electrode (GCE). Several electrochemical techniques such as cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) were employed to evaluate the electrochemical detection of the CRP antigen. This ultrasensitive method for CRP antigen detection exhibited a very good logarithmic plot from −4.52 to −12.05 g mL−1 and a limit of detection (LOD) of 0.9 fg mL−1. The high selectivity, sensitivity, and stability of the developed electrochemical immunosensor would facilitate miniaturization for point-of-care applications and the efficient diagnosis of cardiovascular diseases. [ABSTRACT FROM AUTHOR]

A series of low-cost α-Ni(OH)2/SiO2 catalysts were successfully fabricated by the vapor-induced internal hydrolysis method, then the hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) was investigated by using the ethanol as the hydrogen donor over these as-prepared α-Ni(OH)2/SiO2 catalysts. Based on the reaction results, these as-prepared catalysts, which could dispense with extra pre-reduction treatment before reactions, exhibited superior catalytic performance for the HMF hydrogenation to BHMF. A remarkable intrinsic selectivity of BHMF selectivity of almost 100% with about 90% HMF conversion could be obtained under 195 °C for 5 h in an N2 atmosphere over the α-Ni(OH)2/SiO2 catalyst of 5-Ni(OH)2/SiO2 with about 5 wt% Ni on SiO2. The almost constant HMF conversion and BHMF intrinsic selectivity found from the recycling tests can indicate that the catalyst was stable without the obvious loss of its catalytic activity after recycling. Moreover, the mechanism of HMF hydrogenation using ethanol over the α-Ni(OH)2/SiO2 catalysts could be referred to as the mechanism of the Meerwein-Ponndorf-Verley reaction. This work will provide a simple synthesis method for future design and development of high-performance, low-cost, and low-energy consumption catalysts for HMF hydrogenation to BHMF. [ABSTRACT FROM AUTHOR]

Herein, we report cobalt‐catalyzed hydrogenation and deuteration reactions of bicyclic alkenes using H2O and D2O as the sole hydrogen and deuterium sources, respectively, employing Zn or Mn as a metal reductant. Lewis‐acid co‐catalysts were found to promote the reaction whilst simultaneously catalyzing transesterification processes. Use of 1 atm of H2 allows for catalytic loading of the metal reductant. In all cases, the reaction operated with high functional‐group tolerance and produced reduced products in high yield. [ABSTRACT FROM AUTHOR]

Developing highly effective cheap metal oxides is of great value for the 5-hydroxymethylfurfural (HMF) aerobic oxidation to 2,5-furandicarboxylic acid (FDCA) under environmentally friendly conditions. Herein, we synthesized a non-precious cobalt–bismuth binary oxide with rich oxygen vacancies by a facile malic-acid-assisted method and then employed it as a superior catalyst for the HMF aerobic oxidation to FDCA in water. Given the characterization results, the accession of Bi2O3 made the (311) facet become the preferential orientation plane for Co3O4 in the cobalt–bismuth binary oxide. Then, the oxygen vacancies from Co3O4 will be increased due to the greater exposure of Co2+ on the dominant exposed (311) facet, which in turn will facilitate the aerobic oxidation of HMF to FDCA. Evaluating the performance of cobalt–bismuth binary oxide in HMF oxidation reactions, an outstandingly high FDCA yield of 98.23% with nearly 100% HMF conversion could be found over CoBi-12 (Co/Bi molar ratio of 12 : 1) under 0.6 MPa O2 pressure and 110 °C in water for 3 h. The findings of this study can contribute to the development of efficient non-precious metal-based catalysts for the aqueous-phase aerobic oxidation of biomass-derived HMF. [ABSTRACT FROM AUTHOR]