Synergy of Ag and AgBr in a Pressurized Flow Reactor for Selective Photocatalytic Oxidative Coupling of Methane.

Oxidation of methane into valuable chemicals, such as C2+ molecules, has been long sought after but the dilemma between high yield and high selectivity of desired products remains. Herein, methane is upgraded through the photocatalytic oxidative coupling of methane (OCM) over a ternary Ag-AgBr/TiO2 catalyst in a pressurized flow reactor. The ethane yield of 35.4 µmol/h with a high C2+ selectivity of 79% has been obtained under 6 bar pressure. These are much better than most of the previous benchmark performance in photocatalytic OCM processes. These results are attributed to the synergy between Ag and AgBr, where Ag serves as an electron acceptor and promotes the charge transfer and AgBr forms a heterostructure with TiO2 not only to facilitate charge separation but also to avoid the overoxidation process. This work thus demonstrates an efficient strategy for photocatalytic methane conversion by both the rational design of the catalyst for the high selectivity and reactor engineering for the high conversion.

Bimetallic FeO x -MO x Loaded TiO2 (M = Cu, Co) Nanocomposite Photocatalysts for Complete Mineralization of Herbicides.

A series of monometallic and bimetallic cocatalyst(s), comprising FeO x , CuO x , CoO x , FeO x -CuO x , and FeO x -CoO x loaded TiO2 catalysts prepared by the surface impregnation method, were investigated for the photocatalytic mineralization of the widely used four herbicides: 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). It was found that FeO x -CoO x /TiO2 showed the highest photocatalytic efficiency toward mineralization of selected herbicides. FeO x -CoO x /TiO2 achieves 92% TOC removal in 180 min, representing nearly three time activity of the benchmark PC50 TiO2. From XPS analysis, FeOOH, CuO, and CoO were determined to be loaded onto the TiO2 surface. The outstanding photocatalytic performance of the optimized FeO x -CoO x /TiO2 sample for herbicides mineralization is due to an increased charge separation and enhanced hydroxyl radicals production monitored by diverse spectroscopies. Based on the proposed charge transfer mechanism, FeO x -CoO x cocatalyst species accelerate the transfer of photogenerated holes on TiO2, thus facilitating hydroxyl radicals production.

Insights on Carbon Neutrality by Photocatalytic Conversion of Small Molecules into Value-Added Chemicals or Fuels.

Photocatalytic conversion of small molecules (including H2O, CO2, N2, CH4, and benzene) into value-added chemicals or fuels (e.g., H2, NH3, C2 +, etc.) is a promising strategy to cope with both the worldwide increasing energy demand and greenhouse gas emission in both energy sectors and chemical industry, thus paving an effective way to carbon neutrality. On the other hand, compared with conventionally thermo- or electrocatalytic processes, photoactivation can convert these very stable small molecules by the unexhausted solar energy, so leading to store solar energy in chemical bonds. Thus, it can effectively reduce the reliance on the nonrenewable fossil fuels and avoid the substantial emission of hazardous gases such as CO2, NO x , and so on while producing valued-added chemicals. For example, semiconductors can absorb solar light to split H2O into H2 and O2 or convert CO2 to alcohols, which can then be used as zero or neutral carbon energy sources. Although many efforts have already been made on photocatalytic small molecule activation, the light-energy conversion efficiency is still rather moderate and the yield of aimed value-added chemicals cannot meet the requirement of large-scale application. The core for these artificial photocatalytic processes is to discover a novel photocatalyst with high efficiency, low cost, and excellent durability. Over the past two decades, the Tang group has discovered a few benchmark photocatalysts (such as dual-metal-loaded metal oxides, atomic photocatalysts, carbon-doped TiO2, and polymer heterojunctions, etc.) and investigated them for photocatalytic conversion of the above-mentioned five robust molecules into value-added chemicals or liquid fuels. Besides, advanced photocatalytic reaction systems including batch and continuous flow membrane reactors have been studied. More importantly, the underlying reaction mechanism of these processes has been thoroughly analyzed using the state-of-the-art static and time-resolved spectroscopies. In this Account, we present the group's recent research progress in search of efficient photocatalysts for these small molecules' photoactivation. First, the strategies used in the group with respect to three key factors in photocatalysis, including light harvesting, charge separation, and reactant adsorption/product desorption, are comprehensively analyzed with the aim to provide a clear strategy for efficient photocatalyst design toward small and robust molecule photoactivation under ambient conditions. The application of in situ and operando techniques on charge carrier dynamics and reaction pathway analysis used in the group are next discussed. Finally, we point out the key challenges and future research directions toward each specific small molecule's photoactivation process.

Rational Design of High-Concentration Ti3+ in Porous Carbon-Doped TiO2 Nanosheets for Efficient Photocatalytic Ammonia Synthesis.

Photocatalytic ammonia synthesis is exciting but quite challenging with a very moderate yield at present. One of the greatest challenges is to develop highly active centers in a photocatalyst for N2 reduction under ambient conditions. Herein, porous carbon-doped anatase TiOx (C-TiOx ) nanosheets with high-concentration active sites of Ti3+ are presented, which are produced by layered Ti3 SiC2 through a reproducible bottom-up approach. It is shown that the high-concentration Ti3+ sites are the major species for the significant increase in N2 photoreduction activity by the C-TiOx . Such bottom-up substitutional doping of C into TiO2 is responsible for both visible absorption and generation of Ti3+ concentration. Together with the porous nanosheets morphology and the loading of a Ru/RuO2 nanosized cocatalyst for enhanced charge separation and transfer, the optimal C-TiOx with a Ti3+ /Ti4+ ratio of 72.1% shows a high NH3 production rate of 109.3 µmol g-1 h-1 under visible-light irradiation and a remarkable apparent quantum efficiency of 1.1% at 400 nm, which is the highest compared to all TiO2 -based photocatalysts at present.

LncRNA NRON promotes M2 macrophage polarization and alleviates atrial fibrosis through suppressing exosomal miR-23a derived from atrial myocytes.

BACKGROUND/PURPOSE: miR-23a is a pro-hypertrophic miRNA that inhibits M2 macrophage polarization. A previous study demonstrated that lncRNA NRON alleviated atrial fibrosis through suppression of M1 macrophages activated by atrial myocytes. This study aimed to determine whether NRON promotes M2 macrophage polarization and alleviates atrial fibrosis through suppressing exosomal miR-23a derived from atrial myocytes. METHODS: Mouse atrial myocytes were transfected with the NRON overexpression vector or empty vector, followed by Ang II treatment. Exosomes were isolated from the treated atrial myocytes and then co-cultured with RAW264.7 macrophages. The culture medium from RAW264.7 macrophages treated as described above was added to mouse atrial fibroblasts for incubation. RESULTS: We found that exosomes derived from Ang II-treated atrial myocytes inhibited M2 macrophage polarization by transferring miR-23a. NFATc3 could directly bind to the miR-23a promoter. Overexpression of NRON inhibited the expression of miR-23a by inhibiting NFATc3 nuclear transport in Ang II-treated atrial myocytes, resulting in a decrease in the level of miR-23a in atrial myocyte-derived exosomes. Meanwhile, exosomes derived from NRON-overexpressing atrial myocytes promoted M2 macrophage polarization and inhibited expression of fibrosis markers in atrial fibroblasts. CONCLUSION: NRON promotes M2 macrophage polarization and alleviates atrial fibrosis through suppressing exosomal miR-23a derived from atrial myocytes.

The Perioperative Hyperchloremia Is Associated With Postoperative Acute Kidney Injury in Patients With off-Pump Coronary Artery Bypass Grafting: A Retrospective Study.

BACKGROUND: The relationship between perioperative hyperchloremia and postoperative acute kidney injury (AKI) is not well established. Our study aimed to evaluate the association between perioperative hyperchloremia and acute kidney injury in patients undergoing off-pump coronary artery bypass grafting (CABG). METHODS: Patients with coronary disease who underwent off-pump CABG between April 2017 and December 2019 were enrolled in this retrospective study. The patients with perioperative hyperchloremia were matched 1:1 to patients without perioperative hyperchloremia. The primary outcome was the postoperative acute kidney injury rate. The secondary outcomes included intensive care unit (ICU)-free days, postoperative hospitalization days, wound infection rate, and in-hospital mortality. Propensity score matching and univariate and multivariate logistic regression analyses were used in this study. RESULTS: A total of 321 patients who underwent off-pump CABG were included in the analysis. Propensity score matching selected 83 pairs for the final comparison. The results showed that the postoperative AKI rate was significantly different between the hyperchloremia and no hyperchloremia groups (56.6% versus 15.7%; P < .001). The number of ICU-free days, postoperative hospitalization days, wound infection rate, and in-hospital mortality were similar between the two groups. In the multivariable, logistic regression analysis, hyperchloremia was independently associated with the development of postoperative AKI (odds ratio [OR] = 1.814, 95% confidence interval [CI]: 1.072-3.070, P = .026). CONCLUSIONS: Perioperative hyperchloremia is associated with an increase in the postoperative AKI rate among patients undergoing off-pump CABG.