Graphene oxide as a hole extraction layer loaded on BiVO_(4)photoanode for highly efficient photoelectrochemical water splitting

The tailor-made oxygen evolution catalysts(OECs)paired with photoanodes offer a path to promote water oxidation kinetics;however,the unsatisfied interface between OECs and photoanode sets a barrier for efficient charge transfer.Herein,a graphene oxide(GO)layer to promote the charge transfer from BiVO_(4)(BVO)to NiOOH OEC is reported.It is found that GO layer inserted between BVO and NiOOH can not only serve as hole extraction layer due to its hole storage capability,but also improve the stability.Finally,the rationally designed NiOOH/GO/BVO photoanode achieves a photocurrent density of 3.81 mA·cm^(-2)at 1.23 V(vs.reversible hydrogen electrode(RHE)),which is 3.85 times as high as that of bare BVO.This work opens up low-cost auxiliary materials for enhancing photoelectrochemical water splitting.

Dual-property blue and red emission carbon dots for Fe(Ⅲ)ions detection and cellular imaging

The excitation wavelength-dependent and-independent emissions are two crucial fluorescent properties of carbon dots(CDs).However,CDs reported till date exhibit only one of these properties,which limits their practical applications.Herein,dual-property carbon dots(DCDs)with both the excitation wavelength-dependent and-independent emissions were synthesized via a facile onestep solvothermal method using 4-(2-pyridylazo)-resorcinol as the carbon precursor.The multi-functional applications of the resulting DCDs were also evaluated.The asprepared DCDs exhibited not only excellent monodispersity,high photostability,and storage stability,but also low toxicity,good biocompatibility,and cellular bioimaging capability.In addition,the DCDs exhibited excitation-dependent emission photoluminescence under low excitation wavelengths.The DCDs exhibited good Fe3+detection by quenching the blue emission fluorescence and showed a relatively low Fe3+detection limit of 0.067 lmol·L-1 based on three times signal-to-noise criteria(R2=0.99).Furthermore,the DCDs showed excitation-independent emission at low excitation wavelengths and exhibited red emission at about 598 nm to avoid damage to the body.These results demonstrate the excellent bioimaging properties of the DCDs.Owing to their dual PL properties,the as-prepared DCDs exhibited multi-functional applications:Fe3+detection and A549 cell bioimaging.These results will be helpful in developing novel CDs for applications in various fields.