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Electrochemical CO 2 reduction to value-added chemicals or fuels offers a promising approach to reduce carbon emissions and alleviate energy shortage. Cu-based electrocatalysts have been widely reported as capable of reducing CO 2 to produce a variety of multicarbon products (e.g., ethylene and ethanol). In this work, we develop sulfur-doped Cu 2 O electrocatalysts, which instead can electrochemically reduce CO 2 to almost exclusively formate. We show that a dynamic equilibrium of S exists at the Cu 2 O-electrolyte interface, and S-doped Cu 2 O undergoes in situ surface reconstruction to generate active S-adsorbed metallic Cu sites during the CO 2 reduction reaction (CO 2 RR). Density functional theory (DFT) calculations together with in situ infrared absorption spectroscopy measurements show that the S-adsorbed metallic Cu surface can not only promote the formation of the *OCHO intermediate but also greatly suppress *H and *COOH adsorption, thus facilitating CO 2 -to-formate conversion during the electrochemical CO 2 RR., (© 2023 Wiley-VCH GmbH.)

Self-renewal and differentiation of embryonic stem cells (ESCs) are influenced by protein O-linked β-N-acetylglucosamine (O-GlcNAc) modification, but the underlying mechanism remains incompletely understood. Herein, we report the identification of 979 O-GlcNAcylated proteins and 1340 modification sites in mouse ESCs (mESCs) by using a chemoproteomics method. In addition to OCT4 and SOX2, the third core pluripotency transcription factor (PTF) NANOG was found to be modified and functionally regulated by O-GlcNAc. Upon differentiation along the neuronal lineage, the O-GlcNAc stoichiometry at 123 sites of 83 proteins-several of which were PTFs-was found to decline. Transcriptomic profiling reveals 2456 differentially expressed genes responsive to OGT inhibition during differentiation, of which 901 are target genes of core PTFs. By acting on the core PTF network, suppression of O-GlcNAcylation upregulates neuron-related genes, thus contributing to mESC fate determination., (© 2023 Wiley-VCH GmbH.)

Electrochemical CO 2 reduction to value-added chemicals/fuels provides a promising way to mitigate CO 2 emission and alleviate energy shortage. CO 2 -to-CO conversion involves only two-electron/proton transfer and thus is kinetically fast. Among the various developed CO 2 -to-CO reduction electrocatalysts, transition metal/N-doped carbon (M-N-C) catalysts are attractive due to their low cost and high activity. In this work, recent progress on the development of M-N-C catalysts for electrochemical CO 2 -to-CO conversion is reviewed in detail. The regulation of the active sites in M-N-C catalysts and their related adjustable electrocatalytic CO 2 reduction performance is discussed. A visual performance comparison of M-N-C catalysts for CO 2 reduction reaction (CO 2 RR) reported over the recent years is given, which suggests that Ni and Fe-N-C catalysts are the most promising candidates for large-scale reduction of CO 2 to produce CO. Finally, outlooks and challenges are proposed for future research of CO 2 -to-CO conversion., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Reactive species, such as . PO 2 and HOPO, are considered of upmost importance in flame inhibition and catalytic combustion processes of fuels. However, the underlying chemistry of their formation remains speculative due to the unavailability of suitable analytical techniques that can be used to identify the transient species which lead to their formation. This study elucidates the reaction mechanisms of the formation of phosphoryl species from dimethyl methyl phosphonate (DMMP) and dimethyl methyl phosphoramidate (DMPR) under well-defined oxidative conditions. Photoelectron photoion coincidence techniques that utilized vacuum ultraviolet synchrotron radiation were applied to isomer-selectively detect the elusive key intermediates and stable products. With the help of in situ recorded spectral fingerprints, different transient species, such as PO 2 and triplet O radicals, have been exclusively identified from their isomeric components, which has helped to piece together the formation mechanisms of phosphoryl species under various conditions. It was found that . PO 2 formation required oxidative conditions above 1070 K. The combined presence of O 2 and H 2 led to significant changes in the decomposition chemistry of both model phosphorus compounds, leading to the formation of . PO 2 . The reaction . PO+O 2 → . PO 2 +O: was identified as the key step in the formation of . PO 2 . Interestingly, the presence of O 2 in DMPR thermolysis suppresses the formation of PN-containing species. In a previous study, PN species were identified as the major species formed during the pyrolysis of DMPR. Thus, the findings of this study has shed light onto the decomposition pathways of organophosphorus compounds, which are beneficial for their fuel additive and fire suppressant applications., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The thermal behavior of organophosphorus compounds is intricate and poorly understood but crucial for understanding gas-phase flame inhibition, syntheses of thermally active phosphorus-based reactive precursors, catalytic combustion, incineration of toxic nerve gases, and astrochemistry. In this work, the pyrolysis of dimethyl phosphoramidate was investigated using photoion photoelectron coincidence spectroscopy in combination with vacuum ultraviolet synchrotron radiation. This technique enables isomer-selective detection of reactive intermediates, which are crucial in the understanding of the decomposition process. Combined with quantum chemical calculations, the experimental results permit the formulation of a comprehensive pyrolysis reaction pathway for dimethyl phosphoramidate, consisting of several reactive phosphorus species on four possible decomposition pathways. Compared to the decomposition of dimethyl methyl phosphonate, which leads exclusively to the formation of PO radicals, substitution of the methyl with an amino group most notably yields phosphorus nitride (P≡N). This mostly favored reaction pathway involves the subsequent loss of methanol and formaldehyde to yield three PONH 2 tautomers, which eliminate water to generate P≡N. The thermally induced production of PN species and its possible role in flame inhibition has not previously been reported. In addition, the adiabatic ionization energy of O=P(OCH 3 ) 2 NH 2 was determined to be 9.79±0.02 eV., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The production of phosphoryl species (PO, PO2, HOPO) is believed to be of great importance for efficient flame-retardant action in the gas phase. We present a detailed investigation of the thermal decomposition of dimethyl methylphosphonate (DMMP) probed by vacuum ultraviolet (VUV) synchrotron radiation and imaging photoelectron photoion coincidence (iPEPICO) spectroscopy. This technique provides a snapshot of the thermolysis process and direct evidence of how the reactive phosphoryl species are generated during heat exposure. One of the key findings of this work is that only PO is formed in high concentration upon DMMP decomposition, whereas PO2 is absent. It can be concluded that the formation of PO2 needs an oxidative environment, which is typically the case in a real flame. Based on the identification of products such as methanol, formaldehyde, and PO, as well as the intermediates O=P-CH3, H2C=P-OH, and H2C=P(=O)H, supported by quantum chemical calculations, we were able to describe the predominant pathways that lead to active phosphoryl species during the thermal decomposition of DMMP., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)