Thermal and light irradiation effects on the electrocatalytic performance of hemoglobin modified Co3O4-g-C3N4 nanomaterials for the oxygen evolution reaction

Recent Advances in Graphitic Carbon Nitride Based Electro-Catalysts for CO2 Reduction Reactions

The electrocatalytic carbon dioxide reduction reaction is an effective means of combating the greenhouse effect caused by massive carbon dioxide emissions. Carbon nitride in the graphitic phase (g-C₃N₄) has excellent chemical stability and unique structural properties that allow it to be widely used in energy and materials fields. However, due to its relatively low electrical conductivity, to date, little effort has been made to summarize the application of g-C₃N₄ in the electrocatalytic reduction of CO₂. This review focuses on the synthesis and functionalization of g-C₃N₄ and the recent advances of its application as a catalyst and a catalyst support in the electrocatalytic reduction of CO₂. The modification of g-C₃N₄-based catalysts for enhanced CO₂ reduction is critically reviewed. In addition, opportunities for future research on g-C₃N₄-based catalysts for electrocatalytic CO₂ reduction are discussed.

Size effect of CoS2 cocatalyst on photocatalytic hydrogen evolution performance of g-C3N4

The main goal of researchers is to obtain cheap cocatalysts that can promote the photocatalytic activity of catalysts. In this work, a series of CoS₂/g-C₃N₄ (denoted as CoS₂/CN) composite photocatalysts were synthesized by photodepositing CoS₂ on g-C₃N₄ surface. The size of CoS₂ species could be tuned from single-atom to nanometer scale, which had effect on photocatalysis. The 5CoS₂/CN sample with proper nano size of CoS₂ cocatalyst had the best photocatalytic performance (1707.19 μmol g^-1h^-1) in producing H₂ under visible light irradiation (λ > 420 nm). Its photocatalytic activity was about 1434.6 times higher than that of pure g-C₃N₄ and almost equal with that of Pt/CN catalyst (1799.54 μmol g^-1h^-1). The Density Functional Theory (DFT) calculation results further suggested that the ability of accumulating the electrons of the cocatalyst was based on the size effect of CoS₂, and the proper size of the cocatalyst efficiently promoted the separation of photogenerated electron-hole pairs.

Synthesis of doxorubicin-loaded peptosomes hybridized with gold nanorod for targeted drug delivery and CT imaging of metastatic breast cancer

BACKGROUND

Cancer nanomedicines based on synthetic polypeptides have attracted much attention due to their superior biocompatibility and biodegradability, stimuli responsive capability through secondary conformation change, adjustable functionalities for various cargos such as peptides, proteins, nucleic acids and small therapeutic molecules. Recently, a few nanoformulations based on polypeptides comprising NK105, NC6004, NK911, CT2103, have entered phase I-III clinical trials for advanced solid tumors therapy. In the current study, we prepared polypeptide-based vesicles called peptosome via self-assembly of amphiphilic polypeptide-based PEG-PBLG diblock copolymer.

RESULTS

In this regard, poly(γ-benzyl L-glutamate (PBLG) was synthesized via ring opening polymerization (ROP) of γ-benzyl L-glutamate-N-carboxyanhydride (BLG-NCA) using N-hexylamine as initiator. Then amine-terminated PBLG was covalently conjugated to heterofuctional maleimide PEG-carboxylic acid or methyl-PEG-carboxylic acid. The PEG-PBLG peptosomes were prepared through double emulsion method for the co-delivery of doxorubicin.HCl and gold nanorods as hydrophilic and hydrophobic agents in interior compartment and membrane of peptosomes, respectively (Pep@MUA.GNR-DOX) that DOX encapsulation efficiency and loading capacity were determined 42 ± 3.6 and 1.68 ± 3.6. Then, theranostic peptosomes were decorated with thiol-functionalized EpCAM aptamer throught thiol-maleimide reaction producing Apt-Pep@MUA.GNR-DOX for targeted delivery. The non-targeted and targeted peptosomes showed 165.5 ± 1.1 and 185 ± 4.7 nm diameters, respectively while providing sustained, controlled release of DOX. Furthermore, non-targeted and targeted peptosomes showed considerable serum stability. In vitro study on MCF-7 and 4T1 cells showed significantly higher cytotoxicity for Apt-Pep@MUA.GNR-DOX in comparison with Pep@MUA.GNR-DOX while both system did not show any difference in cytotoxicity against CHO cell line. Furthermore, Apt-Pep@MUA.GNR-DOX illustrated higher cellular uptake toward EpCAM-overexpressing 4T1 cells compared to Pep@MUA.GNR-DOX. In preclinical stage, therapeutic and diagnostic capability of the prepared Pep@MUA.GNR-DOX and Apt-Pep@MUA.GNR-DOX were investigated implementing subcutaneous 4T1 tumor model in BALB/c mice. The obtained data indicated highest therapeutic index for Apt-Pep@MUA.GNR-DOX compared to Pep@MUA.GNR-DOX and free DOX. Moreover, the prepared system showed capability of CT imaging of tumor tissue in 4T1 tumorized mice through tumor accumulation even 24 h post-administration.

CONCLUSION

In this regard, the synthesized theranostic peptosomes offer innovative hybrid multipurpose platform for fighting against breast cancer.

Mechanochemically Synthetized PAN-Based Co-N-Doped Carbon Materials as Electrocatalyst for Oxygen Evolution Reaction

We report a new class of polyacrylonitrile (PAN)-based Co-N-doped carbon materials that can act as suitable catalyst for oxygen evolution reactions (OER). Different Co loadings were mechanochemically added into post-consumed PAN fibers. Subsequently, the samples were treated at 300 °C under air (PAN-A) or nitrogen (PAN-N) atmosphere to promote simultaneously the Co₃O₄ species and PAN cyclization. The resulting electrocatalysts were fully characterized and analyzed by X-ray diffraction (XRD) and photoelectron spectroscopy (XPS), transmission (TEM) and scanning electron (SEM) microscopies, as well as nitrogen porosimetry. The catalytic performance of the Co-N-doped carbon nanomaterials were tested for OER in alkaline environments. Cobalt-doped PAN-A samples showed worse OER electrocatalytic performance than their homologous PAN-N ones. The PAN-N/3% Co catalyst exhibited the lowest OER overpotential (460 mV) among all the Co-N-doped carbon nanocomposites, reaching 10 mA/cm². This work provides in-depth insights on the electrocatalytic performance of metal-doped carbon nanomaterials for OER.