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High-efficiency electrocatalysts for CO2 reduction reaction are extremely desirable to produce valuable hydrocarbon productions, as well as addressing the current environmental challenges. In this work, we introduce a Cu-based metal–organic framework as a catalyst for the efficient and selective reduction of CO2 to CH4 in neutral aqueous electrolytes. Detailed examination of [Cu 4 ZnCl4(btdd)3] (Cu 4 -MFU-4l , H2btdd = bis­(1H-1,2,3-triazolo-[4,5-b],[4′,5′-i])­dibenzo-[1,4]-dioxin) revealed the highest activity for yielding methane with a Faradaic efficiency of 92%/88% and a partial current density of 9.8/18.3 mA cm–2 at a potential of −1.2/–1.3 V (vs RHE). In situ X-ray absorption and infrared spectroscopy spectra, as well as density functional theory calculations, revealed that the in situ generated trigonal pyramidal Cu­(I)­N3 acts as the electrochemical active site and that the strong coordination ability of the Cu­(I)­N3 site and the synergistic effect of adjacent aromatic hydrogen atoms, via hydrogen-bonding interactions, play an important role in stabilizing the key intermediates of carbon dioxide reduction and inhibiting the hydrogen evolution reaction, thus showing a high performance of electroreduction of CO2 to CH4.

Background: Most tumors have an enhanced glycolysis flux, even when oxygen is available, called the aerobic glycolysis or the Warburg effect. Metabolic reprogramming promotes cancer progression, and is even related to the tumorigenesis. However, it is not clear whether the observed metabolic changes act as a driver or a bystander in cancer development. Methods: In this study, the metabolic characteristics of oral precancerous cells and cervical precancerous lesions were analyzed by metabolomics, and the expression of glycolytic enzymes in cervical precancerous lesions was evaluated by RT-PCR and Western blot analysis. Results: In total, 115 and 23 metabolites with reliable signals were identified in oral cells and cervical tissues, respectively. Based on the metabolome, oral precancerous cell DOK could be clearly separated from normal human oral epithelial cells (HOEC) and oral cancer cells. Four critical differential metabolites (pyruvate, glutamine, methionine and lysine) were identified between DOK and HOEC. Metabolic profiles could clearly distinguish cervical precancerous lesions from normal cervical epithelium and cervical cancer. Compared with normal cervical epithelium, the glucose consumption and lactate production increased in cervical precancerous lesions. The expression of glycolytic enzymes LDHA, HK II and PKM2 showed an increased tendency in cervical precancerous lesions compared with normal cervical epithelium. Conclusions: Our findings suggest that cell metabolism may be reprogrammed at the early stage of tumorigenesis, implying the contribution of metabolic reprogramming to the development of tumor.

3-Ethyl-5-trifluoromethyl-1,2,4-triazole is synthesized by a one-pot reaction. Using this asymmetric triazole ligand bearing one trifluoromethyl and one ethyl as side groups, we construct two new porous coordination polymers, MAF-9 and MAF-2F, being isostructural with the classic hydrophobic and flexible materials, FMOF-1 and MAF-2, based on symmetric triazole ligands bearing two trifluoromethyl groups or two ethyl groups, respectively. MAF-9 and MAF-2F can adsorb large amounts of organic solvents but completely exclude water, showing superhydrophobicity with water contact angles of 152o in between those of FMOF-1 and MAF-2. MAF-9 exhibits very large N2-induced breathing and colossal positive and negative thermal expansions like FMOF-1, but the lower molecular weight and smaller volume of MAF-9 give 16% and 4% higher gravimetric and volumetric N2 uptakes, respectively. In contrast, MAF-2F is quite rigid and does not show the inversed temperature-dependent N2 adsorption and large guest-induced expansion like MAF-2. Further, despite the higher molecular weight and larger volume, MAF-2F possesses 6% and 25% higher gravimetric and volumetric CO2 uptakes, respectively. These results can be explained by the different pore sizes and side group arrangements in the two classic framework prototypes, which demonstrate the delicate roles of ligand side groups in controlling porosity, surface characteristic and flexibility.

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