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Nb2O5@carbon/reduced graphene oxide (M-Nb2O5@C/rGO) composites are fabricated by annealing the precursor of graphene oxide supported Nb-based metal organic frameworks for the first time. The lithium ion capacitor using M-Nb2O5@C/rGO as the anode and activated carbon as the cathode delivers a high energy density of 71.5 W h kg−1 and excellent cycling stability. [ABSTRACT FROM AUTHOR]

Based on signal amplification strategy of dendritic mesoporous silica nanospheres loaded with CdSe/ZnS quantum dots (DMSN@QDs), an ultrasensitive electrochemiluminescence (ECL) immunosensor with magnetic separation was constructed for the detection of SARS-CoV-2 nucleocapsid protein (NP). DMSN, a mesoporous material with abundant radial pores, large specific surface area and high porosity, can increase the loading capacity of QDs and hinder their aggregation as the nanocarrier. DMSN@QDs with good ECL efficiency were used as signal labels to construct a sandwich immunosensor. The designed ECL immunosensor displayed a good linear relationship for NP concentrations ranging from 0.005 ng mL−1 to 50 ng mL−1, with a limit of detection of 3.33 pg mL−1. The ECL immunosensor was successfully applied to detect NP in human serum samples with satisfactory recovery. This strategy provided a new method for detecting NP and expanded the application field of DMSN. [ABSTRACT FROM AUTHOR]

It is of great practical importance to design low-cost materials as catalysts for the oxygen reduction reaction (ORR) and as an anode for sodium–ion batteries (SIBs). In this paper, we report a class of nitrogen-doped carbon materials with a three-dimensional nanofibrous network derived from inexpensive biomass bacterial cellulose (BC) for both ORR and SIB applications. The samples were prepared by treating the BC aerogels with various amounts of pyrrole to ensure a uniform coating on the surface of the BC nanofibers, followed by a carbonization process under different temperatures. The products were essentially carbon nanofibers coated by a nitrogen-doped carbon layer and retained the initial structure of BC. The optimum amount of pyrrole was 0.05 mL and the optimum carbonization temperature was 900 °C. Our best catalyst exhibited good electrocatalytic performance and durability in ORR, without the presence of noble metals. An electrode made from the same material has also demonstrated a stable cycling performance and superior rate capability in SIB application. Our work has demonstrated a rational design of electroactive carbon materials from a low-cost precursor. [ABSTRACT FROM AUTHOR]

We have successfully prepared poly (3,4-ethylenedioxythiophene) (PEDOT)/N-doped reduced graphene oxide (N-rGO) by electrodeposition, post-reduction, and doping N atoms with a microorganism (as a green reagent) to modify PEDOT and resolve the exfoliation and fragmentation problems of pristine PEDOT. This modification greatly improves the electrochemical properties of PEDOT, showing great potential for a bio-electrode coating material, which should have excellent electrochemical properties, stability and biocompatibility. The as-prepared PEDOT/N-rGO shows lower impedance, and higher capacitive performance and cyclical stability than pristine PEDOT due to the doping of N-rGO. An MTT assay demonstrates this modified PEDOT has good adhesion, cell viability and proliferation, similar to pristine PEDOT. This indicates that the modification process does not restrain the good biocompatibility of pristine PEDOT, which results from the doping of highly biocompatible N-rGO by this green method. The wrinkled structure, residual oxygen containing functional groups and dopant N atoms of N-rGO lead to the formation of a fluctuating surface and an increase in the hydrophilicity of PEDOT, which increase the specific surface area and cell adhesion in cell culture, respectively. Consequently, this modified PEDOT improves the electrochemical properties, and resolves the exfoliation and fragmentation problems of pristine PEDOT, while still retaining the high biocompatibility of pristine PEDOT, which is promising for a bio-electrode coating material. [ABSTRACT FROM AUTHOR]