No abstract

H 2 could be the most promising, sustainable, and alternative energy source in the foreseeable future. In this study, a gel-like Ag-containing dicyandiamide metal−organic supramolecular network (MOSN) has been prepared as a precursor to synthesize g-C 3 N 4 for photocatalytic H 2 evolution under light irradiation. Ag can be well incorporated into the g-C 3 N 4 structure by using Ag-containing dicyandiamide MOSN as a precursor to produce a metal− semiconductor interface, thereby promoting the charge separation (evidenced by electrochemical impedance spectroscopy and photocurrent density measurement) and ultraviolet−visible light absorption (UV−vis absorption spectroscopy) and photocatalytic activity for H 2 evolution. g-C 3 N 4 derived from the Ag-containing dicyandiamide MOSN exhibits high H 2 evolution after Pt loadings under light irradiation (λ > 400, 450, and 550 nm) in the presence of triethanolamine. In summary, g-C 3 N 4 synthesized from Ag-containing dicyandiamide supramolecules can be used as an effective photocatalyst for H 2 production.

Polymeric nanofibers fabricated via electrospinning are regarded as promising scaffolds for biomimicking a native extracellular matrix. However, electrospun scaffolds have poor porosity, resulting in cells being unable to infiltrate into the scaffolds but grow only on its surface. In this study, we modified regular electrospinning into rotating multichannel electrospinning (RM-ELSP) to produce microparticles and nanofibers simultaneously. Gelatin nanofibers (0.1-1 microm) and polycaprolactone (PCL) microparticles (0.5-10 microm) were formed and well-mixed. Adjusting the concentration of PCL and/or gelatin, we can fabricate various microparticles/nanofibers composites with different sizes of PCL particles and different diameters of gelatin nanofibers depending on their concentrations (2-10%) during electrospinning. Using PCL particles as a pore generator, we obtained gelatin nanofiber scaffolds with controllable pore size and porosity. Cells adhere and grow into the scaffold easily during in vitro cell culture.

CO 2 capture via adsorption has been widely explored and is viewed as one of the most effective and green solutions to address the high CO 2 concentration globally. However, the formation of intermediates during CO 2 adsorption and the synthesis of the adsorbent, activated carbon, still need to be resolved. In this study, potassium citrate-activated carbon (ACK) samples were prepared. The synergistic effects of the potassium content and reaction temperature (600 and 1000 °C) were examined. In the synthesis of potassium citrate-activated carbon, potassium citrate was converted to KOH, K 2 CO 3 , and K 2 O and evaporated as metallic potassium vapor followed by intercalation into the activated carbon lattice, forming a microand mesoporous nanostructure, which is advantageous for CO 2 capture and electrocatalytic reduction. In addition, trace potassium in the ACK sample acted as a reactive site to redistribute and facilitate electron transfer, enabling enhanced CO 2 activation and reduction. The ACK samples exhibited strong dual-site bonding of CO 2 to the Lewis basic sites, forming b-CO 3 2− intermediates by the physical adsorption through the abundant porous structure of the ACK sample and chemical adsorption by its strong Lewis basicity. In summary, our work presents detailed analyses to understand the mechanism of CO 2 adsorption using activated carbon as an effective adsorbent.