Catalytic Electron Transfer Inhibited by Coulomb Blockade in Au Nanoparticles
Sprache des Vortragstitels:
Englisch
Original Tagungtitel:
Focus Session: Novel Approaches to Surface Plasmon Generated Charges and Heat for Photocatalysis I (joint session O/CPP)
Sprache des Tagungstitel:
Englisch
Original Kurzfassung:
Colloidal noble metal nanoparticles (NPs) are excellent catalysts for various chemical redox reactions. They offer alternative reaction pathways and thereby
significantly reduce the activation energy for chemical transformations. There are several strategies to reduce the activation energy for kinetically sluggish catalytic
reactions, e.g. by changing the size, shape and composition of the NPs and also by changing the specific reaction conditions. To investigate the reaction mechanism
of Au NPs of different sizes below 10 nm, we used the 1-electron transferfrom ferricyanide (Fe3+) to ferrocyanide (Fe2+) as a model reaction system. We compared
the reaction rate ofthe conversion from Fe3+ to Fe2+ in the presence and absence ofthe reducing agenttriethanolamine (TEOA). It has been shown thatthe
reaction pathway is significantly altered with and without TEOA. TEOA generally transfers electrons to Au NP and causes a negative charging on the Au NP surface.
Howeve[ if the size of the NPs is very small, especially below 5 nm, the negative charging of the Au NPs is inhibited by the Coulomb blockade effect. As a result, the
subsequent catalytic electron transfer from Au NP to Fe3+ is also inhibited, which decreases the overall Fe3+ reduction rate. These experimental results and
theoretical calculations will help to develop novel metal NPs for various catalytic processes for environmental remediation.