Limits...
Uniform Functionalization of High-Quality Graphene with Platinum Nanoparticles for Electrocatalytic Water Reduction.

Mazzaro R, Boni A, Valenti G, Marcaccio M, Paolucci F, Ortolani L, Morandi V, Ceroni P, Bergamini G - ChemistryOpen (2015)

Bottom Line: The turnover frequency at zero overpotential (TOF0 in 0.1 m phosphate buffer, pH 6.8) was determined to be approximately 4600 h(-1).This remarkably high value is likely due to the optimal dispersion of the platinum nanoparticles on the graphene substrate, which enables the material to be loaded with only very small amounts of the noble metal (i.e., Pt) despite the very highly active surface.This study provides a new outlook on the design of novel materials for the development of robust and scalable water-splitting devices.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Chimica "G. Ciamician", Università di Bologna Via Selmi 2, 40126, Bologna, Italy ; Institute for Microelectronics & Microsystems (IMM)-Bologna, National Research Council (CNR) Via Gobetti 101, 40129, Bologna, Italy.

ABSTRACT
Graphene-metal composites have potential as novel catalysts due to their unique electrical properties. Here, we report the synthesis of a composite material comprised of monodispersed platinum nanoparticles on high-quality graphene obtained by using two different exfoliation techniques. The material, prepared via an easy, low-cost and reproducible procedure, was evaluated as an electrocatalyst for the hydrogen evolution reaction. The turnover frequency at zero overpotential (TOF0 in 0.1 m phosphate buffer, pH 6.8) was determined to be approximately 4600 h(-1). This remarkably high value is likely due to the optimal dispersion of the platinum nanoparticles on the graphene substrate, which enables the material to be loaded with only very small amounts of the noble metal (i.e., Pt) despite the very highly active surface. This study provides a new outlook on the design of novel materials for the development of robust and scalable water-splitting devices.

No MeSH data available.


Related in: MedlinePlus

Comparison between platinum nanoparticles decoration of graphite platelets in the absence (a,b,c) and in the presence (d,e,f) of 1-pyrenecarboxylic acid (PCA). a,d) Low-magnification scanning transmission electron microscope (STEM) micrographs showing the very selective decoration. b,e) High-resolution transmission electron microscopy (HR-TEM) micrographs of platelets surfaces. c,f) Morphology of the particles outside graphene, which are usually aggregated into clusters.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4522175&req=5

fig03: Comparison between platinum nanoparticles decoration of graphite platelets in the absence (a,b,c) and in the presence (d,e,f) of 1-pyrenecarboxylic acid (PCA). a,d) Low-magnification scanning transmission electron microscope (STEM) micrographs showing the very selective decoration. b,e) High-resolution transmission electron microscopy (HR-TEM) micrographs of platelets surfaces. c,f) Morphology of the particles outside graphene, which are usually aggregated into clusters.

Mentions: In order to evaluate the influence and the role of PCA on the selectivity of the decoration and on the morphology of the platinum nanoparticles, we prepared some water dispersions of graphite nanoplatelets, simply sonicating a 2 mg mL−1 solution of graphite powder in distilled water for 24 hours. This dispersion was characterized by a very low degree of exfoliation of graphite; however, it allowed us to investigate decoration with platinum nanoparticles in the absence of any secondary variables, such as the influence of an exfoliating agent or a stabilizer. Using these samples, we performed the synthesis of platinum-nanoparticles, following the same method previously reported, with or without the addition of PCA. In both cases, the TEM images demonstrated a strongly selective decoration of the graphite flakes, as showed in Figure 3 a,d. The sample prepared without PCA shows very nonhomogeneous size and shape distributions for the platinum nanoparticles (Figure 3 b), whereas the sample prepared with PCA displays spherical and well-dispersed particles on the graphite platelets (Figure 3 e). Magnification of the sporadic platinum nanoparticles outside the graphene show in both cases dishomogeneous distributions of size and shape due to aggregation of the particles, emphasizing the differences between nanoparticles on and outside the graphene surface for the sample prepared with PCA (Figure 3 c,f).


Uniform Functionalization of High-Quality Graphene with Platinum Nanoparticles for Electrocatalytic Water Reduction.

Mazzaro R, Boni A, Valenti G, Marcaccio M, Paolucci F, Ortolani L, Morandi V, Ceroni P, Bergamini G - ChemistryOpen (2015)

Comparison between platinum nanoparticles decoration of graphite platelets in the absence (a,b,c) and in the presence (d,e,f) of 1-pyrenecarboxylic acid (PCA). a,d) Low-magnification scanning transmission electron microscope (STEM) micrographs showing the very selective decoration. b,e) High-resolution transmission electron microscopy (HR-TEM) micrographs of platelets surfaces. c,f) Morphology of the particles outside graphene, which are usually aggregated into clusters.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4522175&req=5

fig03: Comparison between platinum nanoparticles decoration of graphite platelets in the absence (a,b,c) and in the presence (d,e,f) of 1-pyrenecarboxylic acid (PCA). a,d) Low-magnification scanning transmission electron microscope (STEM) micrographs showing the very selective decoration. b,e) High-resolution transmission electron microscopy (HR-TEM) micrographs of platelets surfaces. c,f) Morphology of the particles outside graphene, which are usually aggregated into clusters.
Mentions: In order to evaluate the influence and the role of PCA on the selectivity of the decoration and on the morphology of the platinum nanoparticles, we prepared some water dispersions of graphite nanoplatelets, simply sonicating a 2 mg mL−1 solution of graphite powder in distilled water for 24 hours. This dispersion was characterized by a very low degree of exfoliation of graphite; however, it allowed us to investigate decoration with platinum nanoparticles in the absence of any secondary variables, such as the influence of an exfoliating agent or a stabilizer. Using these samples, we performed the synthesis of platinum-nanoparticles, following the same method previously reported, with or without the addition of PCA. In both cases, the TEM images demonstrated a strongly selective decoration of the graphite flakes, as showed in Figure 3 a,d. The sample prepared without PCA shows very nonhomogeneous size and shape distributions for the platinum nanoparticles (Figure 3 b), whereas the sample prepared with PCA displays spherical and well-dispersed particles on the graphite platelets (Figure 3 e). Magnification of the sporadic platinum nanoparticles outside the graphene show in both cases dishomogeneous distributions of size and shape due to aggregation of the particles, emphasizing the differences between nanoparticles on and outside the graphene surface for the sample prepared with PCA (Figure 3 c,f).

Bottom Line: The turnover frequency at zero overpotential (TOF0 in 0.1 m phosphate buffer, pH 6.8) was determined to be approximately 4600 h(-1).This remarkably high value is likely due to the optimal dispersion of the platinum nanoparticles on the graphene substrate, which enables the material to be loaded with only very small amounts of the noble metal (i.e., Pt) despite the very highly active surface.This study provides a new outlook on the design of novel materials for the development of robust and scalable water-splitting devices.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Chimica "G. Ciamician", Università di Bologna Via Selmi 2, 40126, Bologna, Italy ; Institute for Microelectronics & Microsystems (IMM)-Bologna, National Research Council (CNR) Via Gobetti 101, 40129, Bologna, Italy.

ABSTRACT
Graphene-metal composites have potential as novel catalysts due to their unique electrical properties. Here, we report the synthesis of a composite material comprised of monodispersed platinum nanoparticles on high-quality graphene obtained by using two different exfoliation techniques. The material, prepared via an easy, low-cost and reproducible procedure, was evaluated as an electrocatalyst for the hydrogen evolution reaction. The turnover frequency at zero overpotential (TOF0 in 0.1 m phosphate buffer, pH 6.8) was determined to be approximately 4600 h(-1). This remarkably high value is likely due to the optimal dispersion of the platinum nanoparticles on the graphene substrate, which enables the material to be loaded with only very small amounts of the noble metal (i.e., Pt) despite the very highly active surface. This study provides a new outlook on the design of novel materials for the development of robust and scalable water-splitting devices.

No MeSH data available.


Related in: MedlinePlus