Theoretical investigation of the hetero-junction effect in PVP-stabilized Au13 clusters. The role of PVP in their catalytic activities

Hybrid density functional calculations have been carried out for Au13-poly(N-vinyl-2-pyrrolidone), abbreviated as Au13-PVP, and related model clusters, Au13-PVP4, Au13-PVP-O2 and Au13-PVP4-O2, to discuss the variation in the electronic structure of Au13 clusters by PVP adsorption. The calculations have shown that the charge transfer from the adsorbed PVP to Au13 produces negatively charged O2 on Au13-PVP4. These findings suggest that PVP acts not only as a stabilizer to prevent the aggregation of Au clusters but also as an electron donor to Au clusters. Thus we conclude that the catalytic activities of Au clusters are affected by the adsorbed PVPs.