Solvent-Free Photoreduction of CO2 to CO Catalyzed by Fe-MOFs with Superior Selectivity.

It is deemed as a desired approach to utilize solar energy for the conversion of CO2 into valuable products, and the majority of the MOFs-based photocatalytic reductions of CO2 have focused on formic acid (HCOOH) production with an organic solvent as the reaction medium. Herein, we report a solvent-free reaction route for the photoreduction of CO2 catalyzed by Fe-MOFs, namely, NH2-MIL-53(Fe) [(Fe(OH)(NH2-BDC)]•G, NH2-MIL-88B(Fe) [Fe3O(H2O)3(NH2-BDC)3]Cl•G, and NH2-MIL-101(Fe) [Fe3O(H2O)3(NH2-BDC)3]Cl•G (NH2-BDC = 2-aminoterephthalic acid; G = guest and/or solvent molecules). Compared with the orthodox reaction route, the present out-of-the-way photocatalytic reduction of CO2 with superior selectivity to CO occurs at the gas-solid interface. The reaction procedure is environmentally friendly and provides a possibility to address the CO2 emission problem. Importantly, NH2-MIL-101(Fe) shows the highest photocatalytic activity among these Fe-MOFs due to its efficient charge separation and electron transfer.

Porous Metal-Organic Frameworks with Chelating Multiamine Sites for Selective Adsorption and Chemical Conversion of Carbon Dioxide.

A combination of carbon dioxide (CO2) capture and chemical fixation in a one-step process is attractive for chemists and environmentalists. In this work, by incorporating chelating multiamine sites to enhance the binding affinity toward CO2, two novel metal-organic frameworks (MOFs) [Zn2(L)(2,6-NDC)2(H2O)]·1.5DMF·2H2O (1) and [Cd2(L)(2,6-NDC)2]·1.5DMF·2H2O (2) (L = N1-(4-(1 H-1,2,4-triazole-1-yl)benzyl)- N1-(2-aminoethyl)ethane-1,2-diamine, 2,6-H2NDC = 2,6-naphthalenedicarboxylic acid, DMF = N, N-dimethylformamide) were achieved under solvothermal conditions. Both 1 and 2 possess high selectivity for adsorption of CO2 over CH4 at room temperature under atmospheric pressure. Moreover, 1 has one-dimensional tubular channels decorated with multiactive sites including NH2 groups and coordination unsaturated Lewis acid metal sites, leading to efficient catalytic activity for chemical fixation of CO2 by reaction with epoxides to give cyclic carbonates under mild conditions.

Prevalence of subthreshold depression and its related factors in Chinese college students: A cross-sectional study.

Objective: To investigate the prevalence of subthreshold depression among Chinese college students and to explore the related factors. Methods: The research subjects were Chinese college students participating in the "2022 Psychology and Behavior Investigation of Chinese Residents (PBICR-2022)". Data on respondents' general characteristics, quality of life, perceived pressure, family communication, perceived social support, self-efficacy, and depression status were gathered. To investigate the association between each variable and the risk of subthreshold depression, statistical analyses, including chi-square tests and rank sum tests were conducted. Furthermore, a binary stepwise logistic regression was employed to establish the regression model of the factors related to subthreshold depression among Chinese college students. Results: A prevalence of subthreshold depression of about 39.7 % was found among the 8934 respondents. Logistic regression analysis revealed that respondents who are female, have chronic diseases, are in debt, experience significant impacts from epidemic control policies, have lower self-assessed quality of life, experience challenges in family communication, perceive lower social support, have lower self-efficacy, and feel higher perceived pressure are more likely to develop subthreshold depression compared to the control group. (P < 0.05). Conclusion: The prevalence rate of subthreshold depression among Chinese college students was found to be approximately 40 %. Female college students suffering from chronic diseases, with households in debt, greatly impacted by epidemic control policies, and experiencing high perceived stress, may be at risk for subthreshold depression among Chinese college students. On the other hand, strong family communication, perceived social support, and self-efficacy were identified as potential protective factors. In order to facilitate timely screening, diagnosis, and treatment of subthreshold depression in Chinese college students, it is crucial for the government, local communities, colleges, and families to prioritize the mental health of college students and implement targeted measures accordingly.

An iron-nitrogen doped carbon and CdS hybrid catalytic system for efficient CO2 photochemical reduction.

Iron porphyrin and carbon black (CB) were utilized to fabricate an iron-nitrogen doped carbon (Fe-N-C) catalyst to create a new heterogeneous catalytic system with CdS to drive CO2 reduction to CO under UV/vis light (AM 1.5G) irradiation. The system delivers a high CO production yield of 111 mmol gcat-1 and a large turnover number (TON) of 1.22 × 103 in 8 h with a selectivity of 85%, all of which are competitive with state-of-the-art systems. The mechanism of the system was investigated by experimental and theoretical methods indicating that the high affinity between the iron active center and the *COOH intermediate facilitates the brilliant catalytic performance. This work provides a new direction for constructing heterogeneous CO2 photoreduction systems.

Metalloporphyrin Encapsulation for Enhanced Conversion of CO2 to C2H4.

Electrochemical conversion of CO2 into valuable products is a promising approach. Efficient electrocatalysts are highly desirable but remain to be developed. Here, we proposed a molecular encapsulation strategy to enrich intermediates for facilitating electrochemical conversion of CO2 to C2H4. This strategy is combining M-TCPP [M = FeCl, Co, and Ni; TCPP = tetrakis(4-carboxyphenyl) porphyrin] with a Cu-based metal-organic framework (Cu-MOF) to create a series of metalloporphyrin-decorated Cu catalysts with a coral-like shape (named as M-TCPP@Cu). M-TCPP in the catalysts could supply more CO intermediates to the Cu sites, giving high selectivity for producing C2H4 and lowering overpotentials for CO2 reduction. Meanwhile, the coral-like structure of the catalyst with abundant active sites is conducive to mass diffusion and benefits the conversion of CO2. We realized a higher C2H4 Faradaic efficiency (FE) of 33.42% at -1.17 V versus reversible hydrogen electrode (RHE) on the Fe-TCPP@Cu electrode than that on the sole Cu electrode (16.85%, at -1.27 V vs RHE). Furthermore, due to the encapsulated structure resulted from one-pot reaction that ensures the dispersion of active centers in M-TCPP, metalloporphyrin-decorated Cu catalysts show better performance than the physical mixture of Cu-MOFs and M-TPPs (M = FeCl, Co, and Ni; TPP = 5,10,15,20-tetraphenylporphyrin). The results provide a new strategy for the design of high-performance Cu catalysts from Cu-MOFs for CO2 conversion.

Iron(iii)-bipyridine incorporated metal-organic frameworks for photocatalytic reduction of CO2 with improved performance.

Metal-organic frameworks (MOFs) represent an emerging class of platforms to assemble single site photocatalysts for artificial photosynthesis. In this work, we report a new CO2 reduction photocatalyst (UiO-68-Fe-bpy) based on a robust Zr(iv)-MOF platform with incorporated Fe(bpy)Cl3 (bpy refers to the 4'-methyl-[2,2'-bipyridine] moiety) via amine-aldehyde condensation. We show that this hybrid catalyst can reduce CO2 to form CO under visible light illumination with excellent selectivity and enhanced activity with respect to its parent MOF and corresponding homogeneous counterpart. Using steady state and transient absorption (TA) spectroscopy, we show that the enhanced photocatalytic activity of UiO-68-Fe-bpy is attributed to the elongated excited state lifetime of Fe(bpy)Cl3 after being incorporated to the UiO-68-NH2 platform. This work demonstrates the great potential of MOFs as a next generation platform for solar fuel conversion.

Coordination polymers with a pyridyl-salen ligand for photocatalytic carbon dioxide reduction.

A new ligand H2L with pyridine and salen moieties and its coordination polymers (CPs) [Mn(L)Cl]·DMF (1) and [Fe(L)Cl]·DMF (2) were synthesized and their photocatalytic activity for the conversion of CO2 into CO under visible-light irradiation was investigated. This is the first instance of pyridyl-salen-ligand based CPs for photocatalyzing CO2 reduction.

Facet-dependent photocatalytic hydrogen production of metal-organic framework NH2-MIL-125(Ti).

Facet-dependent catalytic activity of hard materials such as metals and metal oxides is well recognized in previous works. However, it has rarely been established for metal-organic frameworks (MOFs), possibly because the soft crystals of MOFs are conceptually different from the hard solids. In this work, the surface structure of the MOF NH2-MIL-125(Ti) has been investigated by density functional theory (DFT) calculations for the first time. These calculations predict that the {110} facet has a surface energy of 1.18 J m-2, which is superior to those of the {001}, {100} and {111} facets. This difference can be attributed to the larger percentage of exposed metal clusters, which can act as active sites in catalysis. Thus, we have devised and successfully obtained a series of nanoscaled NH2-MIL-125(Ti) MOFs with controlled facets both experimentally and theoretically. The sample containing the {110} facet exhibits the highest photocatalytic hydrogen production activity and apparent quantum yield, which are approximately three times those of the sample with a dominant {111} facet.

[Assessment of left ventricular diastolic function by pulsed Doppler tissue imaging in patients with type 2 diabetes mellitus].

OBJECTIVE: To assess the value of pulsed Doppler tissue imaging (PW-DTI) in evaluating the left ventricular diastolic dysfunction (LVDD) in patients with type 2 diabetes mellitus (DM). METHODS: Seventy-seven type 2 diabetic patients and 43 healthy volunteers underwent PW-DTI and mitral inflow pulsed wave Doppler (MPWD). Six positions of the mitral annulus were measured by PW-DTI for early diastolic velocity (Em), end diastolic velocity (Am), Em/Am ratio. Early mitral inflow velocity (E), end mitral inflow velocity (A), left ventricular isovolumetric relaxation (IVRT) and E/A ratio were measured by MPWD. RESULTS: In the diabetic patients, Em, Em/Am and E/A ratios were significantly decreased and Am and A increased with prolonged IVRT. The two examination modalities showed a significant correlation between Em/Am and E/A. The detection rate of LVDD in the diabetic group was 94.81% by PW-DTI and 79.22% by MPWD. CONCLUSION: PW-DTI and MPWD show a significant correlation in assessment of the left ventricular filling, but the former displays better performance in sensitive and accurate diastolic function evaluation and provides early evidence for of diabetic cardiomyopathy of due to its potent ability in differentiation of false-normal presentations.