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.

Multi-shell nanocomposites based multienzyme mimetics for efficient intracellular antioxidation

Oxidative stress is associated with many acute and chronic inflammatory diseases.Development of nanomaterial-based enzyme mimetics for reactive oxygen species(ROS)scavenging is challenging,but holds great promise for the treatment of inflammatory diseases.Herein,we report the highly ordered manganese dioxide encapsulated selenium-melanin(Se@Me@MnO_(2))nanozyme with high efficiency for intracellular antioxidation and anti-inflammation.The Se@Me@MnO_(2)nanozyme is sequentially fabricated through the radical polymerization and the in-situ oxidation-reduction.In vitro experimental results demonstrated that the Se@Me@MnO_(2) nanozyme exhibits multiple enzyme activities to scavenge ROS,including catalase(CAT),glutathione peroxidase(GPx)and superoxide dismutase(SOD).Mechanism researches illustrated that the Se core possesses GPx-like catalytic activity,the Me and the MnO_(2) possess both the SOD-like and the CAT-like activities.What’s more,due to the stable unpaired electrons existing in the nanozyme,the Se,Me and MnO_(2) provide synergistic and fast electron transfer effect to achieve the quickly scavenging of hydrogen peroxide,hydroxyl radical,and superoxide anion.Further in vivo experimental results showed that this biocompatible nanozyme exhibits cytoprotective effects by resisting ROS-mediated damage,thereby alleviating the inflammation.This multienzyme mimetics is believed to be an excellent ROS scavenger and have a good potential in clinical therapy for ROS-related diseases.