Organophosphine ligand derived sandwich-structural electrocatalyst for oxygen evolution reaction

The synchronous construction of metal phosphate and phosphorus-doped carbon structures is of great significance to innovate the design,synthesis,and application of catalysts,as these phosphoruscontaining composite materials have shown a remarkable contribution to electrocatalysts.However,their preparation procedure generally involves using large amounts of excess phosphorus sources for phosphorization,which inevitably release poisonous PH_(3) or dangerous phosphorus vapor.Here,a strategy for in-situ formation of FePO_(4) embedded in P-doped carbon 2D nano film(FePO_(4)/PdC)is developed using a highly integrated precursor,which is a small molecular organophosphine ligand,1,1’bis(diphenylphosphine)ferrocene(DPPF).The multi-source precursor DPPF that contains Fe,P,and C is molecular-vapor-deposited on the nickel foam(NF)supported ZIF-67 nanosheets to obtain the composite catalyst,namely DPPF-500/ZIF-67/NF.FePO_(4)/PdC encapsulated the ZIF-67 derived Co/N-doped carbon matrix(Co NC)to form a sandwich structure FePO_(4)/PdC@CoNC.The constructed catalyst shows good performance for OER,requiring an overpotential of only 297 m V to deliver 600 m A/cm^(2) with a Tafel slope of 42.7 m V dec^(-1).DFT calculations demonstrate that the synergistic effects between the metal active center and P-doped carbon film reduce the energy barriers and improve electron transport.This method of constructing P-containing catalysts overcomes the demand for additional P sources to realize eco-friendly fabrication and yields a unique structure with good catalytic activity.

Cognitive-enhancing effects of hydrolysate of polygalasaponin in SAMP8 mice

Objectives： The aim of the study is to evaluate the cognitive-enhancing effects of hydrolysate of polyga- lasaponin （HPS） on senescence accelerate mouse P8 （SAMP8） mice, an effective Alzheimer＇s disease （AD） model, and to research the relevant mechanisms. Methods： The cognitive-enhancing effects of HPS on SAMP8 mice were assessed using Morris water maze （MWM） and step-through passive avoidance tests. Then N-methyl-D-aspartate （NMDA） receptor subunit expression for both the cortex and hippocampus of mice was observed using Western blot- ting. Results： HPS （25 and 50 mg/kg） improved the escape rate and decreased the escape latency and time spent in the target quadrant for the SAMP8 mice in the MWM after oral administration of HPS for 10 d. Moreover, it decreased error times in the passive avoidance tests. Western blotting showed that HPS was able to reverse the levels of NMDAR1 and NMDAR2B expression in the cortex or hippocampus of model mice. Conclusions： The present study suggested that HPS can improve cognitive deficits in SAMP8 mice, and this mechanism might be associated with NMDA receptor （NMDAR）-related pathways.