Precipitated and chemically-crosslinked laccase over polyaniline nanofiber for high performance phenol sensing.

The present study aims at fabricating a laccase (LAC) based amperometric biosensor for detection of phenolic compounds. LAC was immobilized into the porous matrix of polyaniline nanofibers (PANFs) in a three-step process, consisting of enzyme adsorption, precipitation, and crosslinking (EAPC). Immobilized LAC on PANF in the form of EAPC was highly active and stable when compared to control samples of 'enzyme adsorption (EA)' and 'enzyme adsorption and crosslinking (EAC)' samples.

Raman Evidence for Late Stage Disproportionation in a Li-O2 Battery.

Raman spectroscopy is used to characterize the composition of toroids formed in an aprotic Li-O2 cell based on an activated carbon cathode. The trends in the Raman data as a function of discharge current density and charging cutoff voltage provide evidence that the toroids are made up of outer LiO2-like and inner Li2O2 regions, consistent with a disproportionation reaction occurring in the solid phase. The LiO2-like component is found to be associated with a new Raman peak identified in the carbon stretching region at ∼1505 cm(-1), which appears only when the LiO2 peak at 1123 cm(-1) is present.