Herein, we proposed a new peroxymonosulfate (PMS) activation system employing the Fe(III) doped g-CN (CNF) as catalyst. Quite different from traditional sulfate radical-based advanced oxidation processes (SR-AOPs), the PMS/CNF system was capable of selectively degrading phenolic compounds (e.g., p-chlorophenol, 4-CP) in a wide pH range (3-9) via nonradical pathway. The generated singlet oxygen (O) in the PMS/CNF3 (3.46 wt % Fe) system played negligible role in removing 4-CP, and high-valent iron-oxo species fixated in the nitrogen pots of g-CN (≡Fe═O) was proposed as the dominant reactive species by using dimethyl sulfoxide as a probe compound. The mechanism was hypothesized that PMS was first bound to the Fe(III)-N moieties to generate ≡Fe═O, which effectively reacted with 4-CP via electron transfer. GC-MS analysis indicated that 4-chlorocatechol and 1,4-benzoquinone were the major intermediates, which could be further degraded to carboxylates. The kinetic results suggested that the formation of ≡Fe═O was proportional to the dosages of PMS and CNF3 under the experimental conditions. Also, the PMS/CNF3 system exhibited satisfactory removal of 4-CP in the presence of inorganic anions and natural organic matters. We believe that this study will provide a new routine for effective PMS activation by heterogeneous iron-complexed catalysts to efficiently degrade organic contaminants via nonradical pathway.

Glucose electrolysis offers a prospect of value-added glucaric acid synthesis and energysaving hydrogen production from the biomass-based platform molecules. Here we report that nanostructured NiFe oxide (NiFeO x ) and nitride (NiFeN x ) catalysts, synthesized from NiFe layered double hydroxide nanosheet arrays on three-dimensional Ni foams, demonstrate a high activity and selectivity towards anodic glucose oxidation. The electrolytic cell assembled with these two catalysts can deliver 100 mA cm −2 at 1.39 V. A faradaic efficiency of 87% and glucaric acid yield of 83% are obtained from the glucose electrolysis, which takes place via a guluronic acid pathway evidenced by in-situ infrared spectroscopy. A rigorous process model combined with a techno-economic analysis shows that the electrochemical reduction of glucose produces glucaric acid at a 54% lower cost than the current chemical approach. This work suggests that glucose electrolysis is an energy-saving and cost-effective approach for H 2 production and biomass valorization.

atoms in SACs are chemically bonded to elements on the supports. This unique structural characteristic endows SACs with strong metal support interactions (SMSIs) [6][7][8][9][10] and tailorable homogenized active metal sites. [11][12][13][14] SACs have been found to be very favorable in many fields, including electrocatalysis, [15][16][17][18] organocatalysis, [19][20][21] industrial catalysis, [22][23][24] and others. [25][26][27][28][29][30] Consequently, revealing the atomic structure of the central metal atoms and the SMSI in SACs has become an important subject of research because it provides possibilities for rational design of novel SACs for specific reactions. The recent development of advanced characterization techniques, including aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC-HAADF-STEM), scanning tunneling microscopy images, extended X-ray absorption fine structure (EXAFS) curve fitting, and DFT modeling, provide crucial tools for identifying the atomic structure. [31][32][33][34][35][36][37] Meanwhile, tremendous efforts have been devoted to exploring SMSIs in SACs and their relationship with catalytic properties. [38][39][40][41] However, a systematic understanding of SMSIs Recognizing and controlling the structure-activity relationships of singleatom catalysts (SACs) is vital for manipulating their catalytic properties for various practical applications. Herein, Fe SACs supported on nitrogen-doped carbon (SA-Fe/CN) are reported, which show high catalytic reactivity (97% degradation of bisphenol A in only 5 min), high stability (80% of reactivity maintained after five runs), and wide pH suitability (working pH range 3-11) toward Fenton-like reactions. The roles of different N species in these reactions are further explored, both experimentally and theoretically. It is discovered that graphitic N is an adsorptive site for the target molecule, pyrrolic N coordinates with Fe(III) and plays a dominant role in the reaction, and pyridinic N, coordinated with Fe(II), is only a minor contributor to the reactivity of SA-Fe/CN. Density functional theory (DFT) calculations reveal that a lower d-band center location of pyrrolic-type Fe sites leads to the easy generation of Fe-oxo intermediates, and thus, excellent catalytic properties.

Oxygen vacancies (OVs) play a crucial role in the catalytic activity of metal-based catalysts; however, their activation mechanism toward peroxydisulfate (PDS) still lacks reasonable explanation. In this study, by taking bismuth bromide (BiOBr) as an example, we report an OV-mediated PDS activation process for degradation of bisphenol A (BPA) employing singlet oxygen (1O2) as the main reactive species under alkaline conditions. The experimental results show that the removal efficiency of BPA is proportional to the number of OVs and is highly related to the dosage of PDS and the catalyst. The surface OVs of BiOBr provide ideal sites for the inclusion of hydroxyl ions (HO–) to form BiIII–OH species, which are regarded as the major active sites for the adsorption and activation of PDS. Unexpectedly, the activation of PDS occurs through a nonradical mechanism mediated by 1O2, which is generated via multistep reactions, involving the formation of an intermediate superoxide radical (O2 •–) and the redox cycle of Bi­(III)/Bi­(IV). This work is dedicated to the in-depth mechanism study into PDS activation over OV-rich BiOBr samples and provides a novel perspective for the activation of peroxides by defective materials in the absence of additional energy supply or aqueous transition metal ions.

Demyelinating diseases, such as multiple sclerosis, are known to result from acute or chronic injury to the myelin sheath and inadequate remyelination; however, the underlying molecular mechanisms remain unclear. Here, we performed genome occupancy analysis by chromatin immunoprecipitation sequencing in oligodendrocytes in response to lysolecithin-induced injury and found that Olig2 and its downstream target Gpr17 are critical factors in regulating oligodendrocyte survival. After injury to oligodendrocytes, Olig2 was significantly upregulated and transcriptionally targeted the Gpr17 locus. Gpr17 activation inhibited oligodendrocyte survival by reducing the intracellular cAMP level and inducing expression of the pro-apoptotic gene Xaf1. The protein kinase A signaling pathway and the transcription factor c-Fos mediated the regulatory effects of Gpr17 in oligodendrocytes. We showed that Gpr17 inhibition elevated Epac1 expression and promoted oligodendrocyte differentiation. The loss of Gpr17, either globally or specifically in oligodendrocytes, led to an earlier onset of remyelination after myelin injury in mice. Similarly, pharmacological inhibition of Gpr17 with pranlukast promoted remyelination. Our findings indicate that Gpr17, an Olig2 transcriptional target, is activated after injury to oligodendrocytes and that targeted inhibition of Gpr17 promotes oligodendrocyte remyelination.

The presence of diverse pollutants in water has been threating human health and aquatic ecosystems on a global scale. For more than a century, chemical oxidation using strongly oxidizing species was one of the most effective technologies to destruct pollutants and to ensure a safe and clean water supply. However, the removal of increasing amount of pollutants with higher structural complexity, especially the emerging micropollutants with trace concentrations in the complicated water matrix, requires excessive dosage of oxidant and/ or energy input, resulting in a low cost-effectiveness and possible secondary pollution. Consequently, it is of practical significance but scientifically challenging to achieve selective oxidation of pollutants of interest for water decontamination. Currently, there are a variety of examples concerning selective oxidation of pollutants in aqueous systems. However, a systematic understanding of the relationship between the origin of selectivity and its applicable water treatment scenarios, as well as the rational design of catalyst for selective catalytic oxidation, is still lacking. In this critical review, we summarize the state-of-the-art selective oxidation strategies in water decontamination and probe the origins of selectivity, that is, the selectivity resulting from the reactivity of either oxidants or target pollutants, the selectivity arising from the accessibility of pollutants to oxidants via adsorption and size exclusion, as well as the selectivity due to the interfacial electron transfer process and enzymatic oxidation. Finally, the challenges and perspectives are briefly outlined to stimulate future discussion and interest on selective oxidation for water decontamination, particularly toward application in real scenarios.

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The catalytic activation of peroxymonosulfate (PMS) is under intensive investigation with potentials as an alternative advanced oxidation process (AOP) in wastewater treatment. Among all catalysts examined, Co(II) exhibits the highest reactivity for the activation of PMS, following the conventional Fenton-like mechanism, in which free radicals (i.e., sulfate radicals and hydroxyl radicals) are reckoned as the reactive species. Herein, we report that the primary reactive species (PRS) is proposed to be a Co(II)−PMS complex (Co(II)−OOSO 3 − ), while free radicals and Co(III) species act as the secondary reactive species (SRS) that play a minor role in the Co(II)/PMS process. This Co(II)−OOSO 3 − exhibits several intriguing properties including ability to conduct both one-electrontransfer and oxygen-atom-transfer reactions with selected molecules, both nucleophilic and electrophilic in nature, and strongly pHdependent reactivity. This study provides novel insights into the chemical nature of the Co(II)-catalyzed PMS activation process.