Size‐Dependent Catalytic Behavior of Gold Nanoparticles. Issue 4 (16th December 2021)

• Record Type: Journal Article
• Authors: Liang, Chen; Cheong, Jun Young; Sitaru, Gabriel; Rosenfeldt, Sabine; Schenk, Anna S.; Gekle, Stephan; Kim, II‐Doo; Greiner, Andreas
• Is Part Of: Advanced materials interfaces. Volume 9:Issue 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-12-16
• Subjects: defects in gold nanoparticles -- ligand density -- nitrophenol reduction -- polydiffusion; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202100867
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Gold nanoparticles (AuNP) are widely used for reaction catalysis. The common understanding is that the smaller the particles, the more reactive they are. It is reported here that this is not always the case for citrate (Ct) or polyvinylpyrrolidone (PVP) stabilized AuNP in the catalytic reduction of 4‐nitrophenol with sodium borohydride (NaBH4 ), when the total surface area is kept constant. The results prove that for AuNP in the size range of 10–58 nm, the reactivity increases with increasing particle diameter for the investigated model reaction. The trend of catalytic activity is independent of the conjugated ligands for citrate and PVP ligands. Purely based on size and resulting surface area, the trend in catalytic activity is unexpected. Only a more detailed structural investigation revealed that internal structure parameters like defect tendency also play a strong role. Larger AuNP possess more defects between crystalline domains. Further, the influence of the ligand density on the surface of AuNP and the diffusion effect of reactants are excluded for the nitrophenol reduction. Abstract : Gold nanoparticles (AuNP) of different sizes are investigated in the nitrophenol reduction with keeping the total surface area same. The catalytic activity is found to be higher with AuNP of larger sizes. This observation is linked to more defects populating on the surface of larger AuNP, which might result in more active sites on the surface of AuNP.