Asymmetric Low-Frequency Pulsed Strategy Enables Ultralong CO2 Reduction Stability and Controllable Product Selectivity.

Copper-based catalysts are widely explored in electrochemical CO2 reduction (CO2RR) because of their ability to convert CO2 into high-value-added multicarbon products. However, the poor stability and low selectivity limit the practical applications of these catalysts. Here, we proposed a simple and efficient asymmetric low-frequency pulsed strategy (ALPS) to significantly enhance the stability and the selectivity of the Cu-dimethylpyrazole complex Cu3(DMPz)3 catalyst in CO2RR. Under traditional potentiostatic conditions, Cu3(DMPz)3 exhibited poor CO2RR performance with the Faradaic efficiency (FE) of 34.5% for C2H4 and FE of 5.9% for CH4 as well as the low stability for less than 1 h. We optimized two distinguished ALPS methods toward CH4 and C2H4, correspondingly. The high selectivities of catalytic product CH4 (FECH4 = 80.3% and above 76.6% within 24 h) and C2H4 (FEC2H4 = 70.7% and above 66.8% within 24 h) can be obtained, respectively. The ultralong stability for 300 h (FECH4 > 60%) and 145 h (FEC2H4 > 50%) was also recorded with the ALPS method. Microscopy (HRTEM, SAED, and HAADF) measurements revealed that the ALPS method in situ generated and stabilized extremely dispersive and active Cu-based clusters (∼2.7 nm) from Cu3(DMPz)3. Meanwhile, ex situ spectroscopies (XPS, AES, and XANES) and in situ XANES indicated that this ALPS method modulated the Cu oxidation states, such as Cu(0 and I) with C2H4 selectivity and Cu(I and II) with CH4 selectivity. The mechanism under the ALPS methods was explored by in situ ATR-FTIR, in situ Raman, and DFT computation. The ALPS methods provide a new opportunity to boost the selectivity and stability of CO2RR.

Indium-Based Metal-Organic Framework for High-Performance Electroreduction of CO2 to Formate.

It is urgent to find a catalyst with high selectivity and efficiency for the reduction of CO2 by renewable electric energy, which is the important means to reduce the greenhouse effect. In this work, we report that the metal-organic framework (MOF) indium-based 1,4-benzenedicarboxylate (In-BDC) catalyzes CO2 to formate with a Faradaic efficiency (FEHCOO-) of more than 80% in a wide voltage range between -0.419 and -0.769 V (vs. reversible hydrogen electrode, RHE). In-BDC performs at a maximum FEHCOO- of 88% at -0.669 V (vs. RHE) and a turnover frequency of up to 4798 h-1 at -1.069 V (vs. RHE). The long-term durability of 21 h and reusability of the electrocatalyst are clearly demonstrated. It opens up a new opportunity to utilize MOF with novel metal motifs for the efficient electroreduction of CO2.

Visible-Light-Mediated Decarboxylative Alkylation Cascade Cyano Insertion/Cyclization of N-Arylacrylamides under Transition-Metal-Free Conditions.

The visible-light-mediated decarboxylative functionalization of aliphatic carboxylic acids using organocatalysts has rarely been reported. This study represented an environmentally benign decarboxylation method involving the combination of eosin Y and (NH4)2S2O8. This system converted aliphatic carboxylic acids to alkyl radicals, followed by their addition to the carbon-carbon double bond of the N-arylacrylamide cascade cyano insertion/cyclization to construct alkylated phenanthridines in moderate to good yields under photoredox catalysis.

Radical Addition/Insertion/Cyclization Cascade Reaction To Assemble Phenanthridines from N-Arylacrylamide Using Cyano as a Bridge under Photoredox Catalysis.

A radical addition/nitrile insertion/homolytic aromatic substitution (HAS) cascade reaction to prepare 6-quaternary alkylated phenanthridines was developed. The addition of the active methylene radicals which were generated from 2-bromoacetonitrile, ethyl 2-bromoacetate, 2-bromo-N,N-dimethylacetamide, or 2-bromo-1-phenylethan-1-one to carbon-carbon double bonds of N-arylacrylamides followed by the cyano-participating sequential cyclization produced a series of phenanthridines in moderate to good yields under photoredox catalysis.

Customized Vascular Repair Microenvironment: Poly(lactic acid)-Gelatin Nanofibrous Scaffold Decorated with bFGF and Ag@Fe3O4 Core-Shell Nanowires.

Vascular defects caused by trauma or vascular diseases can significantly impact normal blood circulation, resulting in serious health complications. Vascular grafts have evolved as a popular approach for vascular reconstruction with promising outcomes. However, four of the greatest challenges for successful application of small-diameter vascular grafts are (1) postoperative anti-infection, (2) preventing thrombosis formation, (3) utilizing the inflammatory response to the graft to induce tissue regeneration and repair, and (4) noninvasive monitoring of the scaffold and integration. The present study demonstrated a basic fibroblast growth factor (bFGF) and oleic acid dispersed Ag@Fe3O4 core-shell nanowires (OA-Ag@Fe3O4 CSNWs) codecorated poly(lactic acid) (PLA)/gelatin (Gel) multifunctional electrospun vascular grafts (bAPG). The Ag@Fe3O4 CSNWs have sustained Ag+ release and exceptional photothermal capabilities to effectively suppress bacterial infections both in vitro and in vivo, noninvasive magnetic resonance imaging (MRI) modality to monitor the position of the graft, and antiplatelet adhesion properties to promise long-term patency. The gradually released bFGF from the bAPG scaffold promotes the M2 macrophage polarization and enhances the recruitment of macrophages, endothelial cells (ECs) and fibroblast cells. This significant regulation of diverse cell behavior has been proven to be beneficial to vascular repair and regeneration both in vitro and in vivo. Therefore, this study supplies a method to prepare multifunctional vascular-repair materials and is expected to represent a significant guidance and reference to the development of biomaterials for vascular tissue engineering.

Ultrathin 2D nickel zeolitic imidazolate framework nanosheets for electrocatalytic reduction of CO2.

Ultrathin 2D nickel(II) (Ni2+) and imidazole (Im) based zeolitic imidazolate framework Ni(Im)2 nanosheets are reported as exceptional efficient electrocatalysts for the electrocatalytic CO2 reduction reaction. Five nanometre thick nanosheets have a higher faradaic efficiency of 78.8% and a surface active site density of 1.68 × 10-7 mol cm-2, which is superior to those of thicker nanosheets and bulk Ni(Im)2.