Influence of the Capping Agent PVP of the Outer Layer of Pd Nanocubes Surface on the Catalytic Hydrogenation of Unsaturated C−C Bonds

Abstract

The excess of capping agents used during the synthesis of nanoparticles is usually removed by solvent washing. The influence of the amount of polyvinylpyrrolidone (PVP) capping agent in the catalytic activity of palladium nanocubes was evaluated, after different numbers of washing cycles in the purification step performed after the syntheses of the nanoparticles. The effect of PVP amount on the hydrogenation of unsaturated carbon-carbon bonds was evaluated in terms of kinetic analysis and diffusion experiments. Five different catalysts were prepared utilizing the washing off procedure. All catalysts were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, small angle X-ray scattering spectroscopy and dynamic light scattering. The reaction presented strong influence by the amount of PVP, which was determined to be due to a balance between the amount of capping agent and the structure of the substrate.

Small Angle Scattering Techniques for the Study of Catalysts and Catalytic Processes

“…[46a] ruled out when comparing their catalytic activities. [51] Similar structure analysis can be found for ZnO, [52] ZrO 2 , [53] WO 3 , [54] Pd, [55] Pt, [21b,56] and Au [57] nanoparticles.…”

“…analysed the influence of the PVP capping agent used for protecting Pd NPs on the hydrogenation of unsaturated carbon‐carbon bonds. Given that the X‐Ray scattering parameters agreed with Transmission Electron Microscopy (TEM) observations, they concluded that the NPs mean size were not affected by the purification procedure, and could be ruled out when comparing their catalytic activities [51] . Similar structure analysis can be found for ZnO, [52] ZrO 2 , [53] WO 3 , [54] Pd, [55] Pt, [21b,56] and Au [57] nanoparticles.…”

Polyethylenimine as a Versatile Simultaneous Reducing and Stabilizing Agent Enabling One-Pot Synthesis of Transition-Metal Nanoparticles: Fundamental Aspects and Practical Implications

“…The catalytic performance is influenced by the chemical nature of the stabilizer 25 and the respective degree of coating (how densely the metallic nanoparticles are coated by the polymer chains). 26 The key influence of the polymer capping was also evidenced by us with regard to biological properties. 21 The antimicrobial effect of AgNPs seems to be suppressed depending on the synthetic route and chemical nature of the capping agent used in their manufacturing.…”

“…The organic shell might, nevertheless, influence the applicability of the produced colloidal material since the capping agent is able to influence antimicrobial properties and catalytic activity. , From the catalytic point of view, the adverse impact of capping agents is a consensus because it hampers the access of the reactants to the catalyst surface, , although their presence is inevitable to promote colloidal stability. The catalytic performance is influenced by the chemical nature of the stabilizer and the respective degree of coating (how densely the metallic nanoparticles are coated by the polymer chains) . The key influence of the polymer capping was also evidenced by us with regard to biological properties .…”

Novel strategy for high-performance supercapacitors through the polyvinylpyrrolidone (PVP)-assisted in situ growth of FeS2

“…[39][40][41] Moreover, PVP increases the nanoparticle stability and reactivity of nanoparticles. 42,43 Aslan et al also reported that PVP could be used as a binding agent to bind the active materials into the current collector for supercapacitor applications. 44 However, PVP's role in enhancing the electrochemical properties has not been clarified yet.…”