Protonated oxygen-containing monofunctional compounds react with selected methoxyborane reagents by proton transfer followed by nucleophilic substitution of methanol at the boron atom in a Fourier transform ion cyclotron resonance mass spectrometer. The derivatized oxygen functionality can be identified by H/D exchange, collision-activated dissociation, or both. This information on the identity of the functionalities in the analyte, in conjunction with molecular formula information obtained from exact mass measurements on either the protonated or derivatized analyte, facilitates structure elucidation of unknown organic compounds in a mass spectrometer.
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http://dx.doi.org/10.1021/ac034946d | DOI Listing |
Angew Chem Int Ed Engl
November 2024
Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, State Key Laboratory of Powder Metallurgy, School of Physics, Central South University, 410083, Changsha, China.
In oxygen reduction reaction to HO via two-electron pathway (2e ORR), adsorption strength of oxygen-containing intermediates determines both catalytic activity and selectivity. However, it also causes activity-selectivity trade-off. Herein, we propose a novel strategy through modulating the interaction between protons and *OOH intermediates to break the activity-selectivity trade-off for highly active and selective 2e ORR.
View Article and Find Full Text PDFSmall Methods
October 2024
College of Science, Sichuan Agricultural University, Xin Kang Road, Ya'an, Yucheng, 625014, P.R. China.
Efficient, stable, and low-cost oxygen reduction catalysts are the key to the large-scale application of metal-air batteries. Herein, high-dispersive FeO nanoparticles (NPs) with abundant oxygen vacancies uniformly are anchored on lignin-derived metal-nitrogen-carbon (M-N-C) hierarchical porous nanosheets as efficient oxygen reduction reaction (ORR) catalysts (FeO/M-N-C, M═Cu, Mn, W, Mo) based on a general and economical KCl molten salt-assisted method. The combination of Fe with the highly electronegative O induces charge redistribution through the Fe-O-M structure, thereby reducing the adsorption energy of oxygen-containing substances.
View Article and Find Full Text PDFAdv Mater
October 2024
Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin, 150080, China.
Modulating the electronic structure of catalysts to effectively couple the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for developing high-efficiency anion exchange membrane water electrolyzer (AEMWE). Herein, a coral-like nanoarray composed of nanosheets through the synergistic layering effect of cobalt and the 1D guiding of vanadium is synthesized, which promotes extensive contact between the active sites and electrolyte. The HER and OER activities can be enhanced by modulating the electronic structure through nitridation and phosphorization, respectively, enhancing the strength of metal-H bond to optimize hydrogen adsorption and facilitating the proton transfer to improve the transformation of oxygen-containing intermediates.
View Article and Find Full Text PDFChem Soc Rev
August 2024
Division of Nanomaterials & Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.
Proton exchange membrane fuel cells (PEMFCs), as a feasible alternative to replace the traditional fossil fuel-based energy converter, contribute significantly to the global sustainability agenda. At the PEMFC anode, given the high exchange current density, Pt/C is deemed the catalyst-of-choice to ensure that the hydrogen oxidation reaction (HOR) occurs at a sufficiently fast pace. The high performance of Pt/C, however, can only be achieved under the premise that high purity hydrogen is used.
View Article and Find Full Text PDFWater Res
November 2024
College of Environmental Sciences and Engineering, Peking University, Beijing 100871, P. R. China.
Low molecular weight organic acids (LMWOA) are commonly present in natural water and play a pivotal role in the reduction of Cr(VI). In frozen solutions, the efficiency of Cr(VI) reduction is significantly enhanced due to the freezing concentration effect. However, this facilitation is found to be contingent upon the functional groups of LMWOA in this study.
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