Exploring cost‐effective and efficient metal‐free electrocatalysts for the oxygen reduction reaction (ORR) is crucial for the development of energy conversion and storage technologies. Reported here is a novel heterocyclization strategy to construct efficient ORR catalysts based on linear conjugated polymers (LCPs), which are composed of N‐, S‐, or Se‐heterocycles. Among these polymers, the covalently linked pyridine and thiophene molecule (P‐T) with reduced graphene oxide (rGO) exhibits a remarkable half‐wave potential of 0.79 V (vs. RHE) and excellent electrochemical stability, which are among the highest values for metal‐free polymers as ORR catalysts. Density‐functional theory (DFT) calculations reveal that the molecule with a phenyl unit (P‐Ph) is catalytically inactive, and when a thiophene unit is introduced to replace the phenyl unit in the conjugated backbone it features highly efficient electrocatalytic active sites. More importantly, the well‐defined molecular structures and controllable active sites in the pyrolysis and metal‐free polymers highlight new opportunities for the catalytic metal‐free ORR.

In recent years, as a new type of carbon dots, carbonized polymer dots (CPDs) have attracted more and more attention in many fields. In this experiment, a new kind of CPDs was synthesized by the hydrothermal treatment of the chemically cross-linked sodium alginate (SA) via glutaraldehyde. The fluorescence of CPDs was greatly enhanced because of the cross-linking enhanced emission effect. The formation process of CPDs at different reaction temperatures was explored. In addition, it was found that CPDs have stable fluorescence properties in mild acidic/basic and metal-ion environments. The in vitro toxicity of CPDs was tested, and based on their nontoxic property, SA films with anti-ultraviolet aging properties were prepared by using CPDs as the additive.

Exploring cost-effective and efficient metal-free electrocatalysts for the oxygen reduction reaction (ORR) is crucial for the development of energy conversion and storage technologies.R eported here is an ovel heterocyclization strategy to construct efficient ORR catalysts based on linear conjugated polymers (LCPs), which are composed of N-, S-, or Se-heterocycles.A mong these polymers,t he covalently linked pyridine and thiophene molecule (P-T)with reduced graphene oxide (rGO) exhibits ar emarkable half-wave potential of 0.79 V(vs.RHE) and excellent electrochemical stability,which are among the highest values for metal-free polymers as ORR catalysts.D ensity-functional theory (DFT) calculations reveal that the molecule with ap henyl unit (P-Ph)i sc atalytically inactive,and when athiophene unit is introduced to replace the phenyl unit in the conjugated backbone it features highly efficient electrocatalytic active sites.M ore importantly,t he well-defined molecular structures and controllable active sites in the pyrolysis and metal-free polymers highlight new opportunities for the catalytic metal-free ORR.

Alginate materials with the advantages of being renewable, inexpensive, and environment-friendly have been considered promising fiber materials. However, they are prone to degrade under UV light, limiting their large-scale application in the textile field. Herein, the fracture of glycosidic bonds during the degradation process is revealed clearly by Fourier transform infrared (FT-IR) and 1 H NMR. To effectively inhibit this process, functionalized multiwalled carbon nanotubes (MWCNTs) are chosen as dopants and used to interact with the sugar chain via hydrogen bonds. The results demonstrate that alginate materials with functionalized MWCNTs exhibit slower degradation rates. The intermolecular energy transfer between functionalized MWCNTs and sodium alginate (SA) is proposed for the antidegradation effect of functionalized MWCNTs, which is supported by the experiments. Moreover, SA/MWCNT fibers also show enhanced mechanical properties compared with pure alginate fibers. The appealing effect of the degradation inhibition feature makes the composite alginate materials very promising candidates for their future use in textile material development.