Catalytic activation of nitrobenzene on PVP passivated silver cluster: A DFT investigation

Abstract

Poly(N‐vinyl‐2‐pyrrolidone) (PVP) has been used extensively to stabilize the surface of noble metal nanoparticles against aggregation and also to produce anisotropic nanostructures. Naturally, it is very important to understand the effect of such surface stabilization by PVP on the catalytic activity of these nanoparticles. This communication investigates through DFT calculations the electronic properties of PVP stabilized 13‐atom Ag cluster for catalytic activation of nitrobenzene (NB). These computations suggest that poly(N‐vinyl‐2‐pyrrolidone) (PVP) interact with silver (Ag) cluster mainly through oxygen atom and acts not only as a stabilizer to prevent the aggregation of Ag clusters but also as an electron donor to activate the Ag clusters for further reaction. Natural Bonding Orbital (NBO) calculations show that catalytic activation of NB by PVP passivated Ag cluster occurs due to interaction of the oxygen of the nitro group with the Ag cluster. Weak back donation of electrons from M(dπ) orbital of Ag to antibonding σ* of one of the NO bond, facilitates the formation of the nitroso intermediate. To understand the extent and the nature of this interaction better, vibrational frequency calculation of nitrobenzene association with Ag13‐2PVP cluster is carried out. Red shift in the frequencies is consequence of strong interaction with that of silver cluster present in Ag13‐2PVP‐NB model.

Supported nanocatalysts: recent developments in microwave synthesis for application in heterogeneous catalysis

“…6 Modification of transition metal nanocatalysts with functionalizing agents such as surfactants 7,8 or polymers 9 has helped to improve stability against aggregation but such modification often deteriorates the catalytic properties via changes in the electronic structure of metal nanocatalysts. 10 The alternative way proposed to overcome the aggregation and deterioration of catalytic property is the implanting or anchoring of nanocatalysts on inert low density solid supports. The solid supports help to maintain the size, shape, morphology of nanocatalysts and also limit the leaching of metal ions favorable for achieving durable and enhanced catalytic performance.…”

Experimental and DFT calculation study of interaction between silver nanoparticle and 1-butyl-3-methyl imidazolium tetrafluoroborate ionic liquid

“…Moreover, limited studies have taken up the issue of effect of IL stabilization on the catalytic properties of these particles. This becomes topical in view of the fact that a few recent experimental as well as theoretical investigations have shown that many macromolecules (other than ILs) stabilizing nanoparticles also affect their electronic structures and thereby their catalytic activity [4,5,6]. Imidazolium based ionic liquids have highly structural organization at nanoscale level and in the condensed phase [7], containing supramolecular networks held together by hydrogen bonds and πÀπ stacking between imidazolium rings [8,9] Synthesis, interaction and organization of NPs in ILs have been explained deeply by He et.al [10].…”

Gold‐Palladium Nanocluster Catalysts for Homocoupling: Electronic Structure and Interface Dynamics

“…PVP has not only been shown to stabilize NCs in solution but also has been shown to actively take part in the catalytic process by altering the electronic distribution and hence enhancing the catalytic activity of the NCs. [41,49,50] The concentration and length of PVP and stabilizers in general also has a significant effect on the size and shape of nanoparticles synthesized. The structures and dynamics of polymer dispersed NCs are poorly understood and NC catalyzed reaction modeling is usually carried out on pristine clusters.…”