Control of Gradient Concentration Prussian White Cathodes for High-Performance Potassium-Ion Batteries.

Owing to their abundant resources and low cost, potassium-ion batteries (PIBs) have become a promising alternative to lithium-ion batteries (LIBs). However, the larger ionic radius and higher mass of K+ propose a challenging issue for finding suitable cathode materials. Prussian whites (PWs) have a rigid open framework and affordable synthesis method, but they suffer quick capacity fade due to lattice volume change and structural instability during K+ insertion/extraction. Here, we prepared controllable gradient concentration KxFeaNibMn1-a-b[Fe(CN)6]y·zH2O particles via a facile coprecipitation process, demonstrating high-performance potassium-ion storage. The high-Mn content in the interior can minimize capacity loss caused by electrochemically inert Ni and achieve a high reversible capacity; meanwhile, the high-FeNi content in the exterior can alleviate the volume change of the core material upon cycling, thus enhancing structural stability. Taking the above synergistic effect, the controllable gradient concentration PWs deliver a high reversible capacity of 109.8 mAh g-1 at 100 mA g-1 and good capacity retention of 77.8% after 200 cycles. The gradient concentration PWs can retain structural integrity and stability during long-term cycling. This work provides a prospective strategy to fabricate PWs with stable structure and excellent electrochemical performance for developing high-performance PIBs.

Prebiotic inulin nanocoating for pancreatic islet surface engineering.

Pancreatic islet surface engineering has been proposed as an "easy-to-adopt" approach to enhance post-transplantation islet engraftment for treatment against diabetes. Inulin is an FDA-approved dietary prebiotic with reported anti-diabetic, anti-inflammatory, anti-hypoxic and pro-angiogenic properties. We therefore assessed whether inulin would be a viable option for islet surface engineering. Inulin was oxidized to generate inulin-CHO, which would bind to the cell membrane via covalent bond formation between -CHO and -NH2 across the islet cell membrane. In vitro assessments demonstrated enhanced islet viability and better glucose-induced insulin secretion from inulin-coated (5 mg mL-1) islets, which was accompanied by enhanced revascularization, shown as significantly enhanced tube formation and branching of islet endothelial MS1 cells following co-culture with inulin-coated islets. Reduction of cytokine-induced cell death was also observed from inulin-coated islets following exposure to pro-inflammatory cytokine LPS. LPS-induced ROS production was significantly dampened by 44% in inulin-coated islets when compared to controls. RNA-seq analysis of inulin-coated and control islets identified expression alterations of genes involved in islet function, vascular formation and immune regulation, supporting the positive impact of inulin on islet preservation. In vivo examination using streptozotocin (STZ)-induced hyperglycemic mice further showed moderately better maintained plasma glucose levels in mice received transplantation of inulin-coated islets, attributable to ameliorated CD45+ immune cell infiltration and improved in vivo graft vascularization. We therefore propose islet surface engineering with inulin as safe and beneficial, and further assessment is required to verify its applicability in clinical islet transplantation.

Highly efficient adsorption behavior and mechanism of Urea-Fe3O4@LDH for triphenyl phosphate.

The emergence of organophosphorus flame retardants and the efficient removal from aquatic environments have aroused increasing concerns. The Urea functionalized Fe3O4@LDH (Urea-Fe3O4@LDH) was prepared and used to adsorb triphenyl phosphate (tphp) for the first time. The tphp adsorption capacity was up to 589 mg g-1, and the adsorption rate reached 49.9 mg g-1 min-1. Moreover, the influences of various environmental factors (pH, ionic strength and organic matter) on the tphp adsorption on the Urea-Fe3O4@LDH were investigated. The initial pH of the solution significantly affected the tphp adsorption, whereas the ionic strength and HA slightly affected the adsorption. The main adsorption mechanism was attributed to electrostatic interaction and π-π interaction. We believe that urea is one of excellent functional groups for the tphp adsorption removal and the materials with urea groups as the adsorbents exhibit good prospects in the future.

Oxygen vacancy enhancing the Fe2O3-CeO2 catalysts in Fenton-like reaction for the sulfamerazine degradation under O2 atmosphere.

To develop an efficient and reusable heterogeneous Fenton-like catalyst is a great challenge for its application in practical water treatment. Effective oxygen vacancy (OVs)-promoted Fe2O3-CeO2 catalyst was prepared by a sol-gel method, and applied in the heterogeneous Fenton-like reaction of the sulfamerazine (SMR) degradation. The Fe2O3-CeO2 catalyst showed good activity and stability, and total SMR conversion was achieved in the Fenton-like reaction after 75 min at pH 3.0 and 45 °C under O2 atmosphere. Moreover, the SMR removal was significantly enhanced under O2 atmosphere. The surface-bounded OH radicals played a dominant role for the SMR degradation. The Fe2O3-CeO2 catalyst remarkably promoted the generation of OH in the Fenton-like reaction under O2 atmosphere, mostly because abundant OVs on the catalyst surface not only accelerated electron transfer to promote the H2O2 decomposition, but also oxygen molecules, adsorbed on OVs, formed O2-/HO2 and promoted the Fe2+/Fe3+ redox cycle.