Scofieldren

Weekly Report 5&6

In the fifth week, I have made a partial surveyon the topic that tunnelling current noise and active sites, as well as in-situor operando conditions. The related articles published in web of science arealmost made by Aliaksandr, even the different keywords have been searched.Their works I focus on are all related to how to identify the electrocatalyticsurface sites by EC-STM in reaction conditions. After learning about the paperpublished in Nature on the current noise and active sites, I have read their articletitled “In situ Quantification of the Local Electrocatalytic Activity viaEC-STM”. The author elaborated a new method for the in-situ quantification ofthe electrocatalytic activity. And they found the linear correlation betweenthe noise and activity levels, which can be determined in terrace and stepssites, respectively. Last, the author introduced the enhancement factor TOFs/TOF,which serves as a descriptor for the activity of the sample.

In addition, I have learnt about the partial applicationof Kelvin probe force microscopy (KPFM), which used for imaging of anisotropiccharge and characterizing charge distribution in complex molecular system andon surfaces. The related research published in Science opened a new way thatdirect experimental visualization to characterize biological and chemicalsystems. A brief understanding on the origin of the electrostatic interactionof KPFM, offered by supporting information, demonstrated that how to obtain thecontact potential difference VCPD. The detail, is that to make analignment of the Fermi level of the tip and sample before they were connectedby an electric circuit. After that, the difference between work function ofsample and tip caused charge transfer between sample and tip. Meanwhile, thechange of field forming in interface will be compensated by an external bias,and therefore allows one to determine the contact potential difference VCPD.The contact potential difference VCPD will be reflected by the vertex of ∆f-V parabola.