Surface heterogeneity of metals of the copper group in the catalytic decomposition of hydrogen peroxide

Bliznakov, G.; Lazarov, D.

doi:10.1016/0021-9517(69)90424-2

Cited by 10 publications

(3 citation statements)

References 2 publications

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“…Our characterization results showed that heating affects both particle size and abundance of chemisorbed oxygen at the surface of Pt nanocatalysts. This is important because particle size and surface chemistry directly affect the catalytic activity of Pt nanoparticles in a variety of chemical reactions, such as (de)hydrogenation reactions, carbon monoxide oxidation, oxygen reduction reaction, ,,, and decomposition of H 2 O 2 . ,,, Changes in particle size affect the position and shape of the valence band and consequently the surface work function . Larger Pt nanoparticles exhibit lower work function values, which correlate with a lower oxidation potential and confer greater capacity to provide electron density to the reagents. , Heating Pt in the presence of oxygen promotes dissociative oxygen chemisorption onto its surface and decomposition of surface PtO x species. , This is important for the present study because weakly interacting surface oxygen species have been linked to enhanced activity in chemical reactions that involve transference of oxygen atoms. ,, …”

Section: Resultsmentioning

confidence: 99%

“…This is important because particle size and surface chemistry directly affect the catalytic activity of Pt nanoparticles in a variety of chemical reactions, such as (de)hydrogenation reactions, 109 carbon monoxide oxidation, 110 oxygen reduction reaction, 59,60,111,112 and decomposition of H 2 O 2 . 29,81,82,113 Changes in particle size affect the position and shape of the valence band and consequently the surface work function. 114 Larger Pt nanoparticles exhibit lower work function values, which correlate with a lower oxidation potential and confer greater capacity to provide electron density to the reagents.…”

Section: Acs Applied Energy Materialsmentioning

confidence: 99%

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Abundance and Speciation of Surface Oxygen on Nanosized Platinum Catalysts and Effect on Catalytic Activity

Serra-Maia

Winkler

Murayama

et al. 2018

ACS Appl. Energy Mater.

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Oxygen at the surface of nanosized platinum has a direct effect on catalytic activity of oxidation−reduction chemical reactions. However, the abundance and speciation of oxygen remain uncertain for platinum with different particle size and shape characteristics, which has hindered the development of fundamental property− activity relationships. We have characterized two commercially available platinum nanocatalysts known as Pt black and Pt nanopowder to evaluate the effects of synthesis and heating conditions on the physical and surface chemical properties, as well as on catalytic activity. Characterization using complementary electron microscopy, X-ray scattering, and spectroscopic methods showed that the larger average crystallite size of Pt nanopowder (23 nm) compared to Pt black (11 nm) corresponds with a 70% greater surface oxygen concentration. Heating the samples in air resulted in an increase in surface oxygen concentration for both nanocatalysts. Surface oxygen associated with platinum is in the form of chemisorbed oxygen, and no significant amounts of chemically bonded platinum oxide were found for any of the samples. The increase in surface oxygen abundance during heating depends on the initial size and surface oxygen content. Hydrogen peroxide decomposition rate measurements showed that larger particle size and higher surface chemisorbed oxygen correlate with enhanced catalytic activity. These results are particularly important for future studies that aim to relate the properties of platinum, or other metal nanocatalysts, with surface reactivity.

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Section: Resultsmentioning

confidence: 99%

Section: Acs Applied Energy Materialsmentioning

confidence: 99%

Abundance and Speciation of Surface Oxygen on Nanosized Platinum Catalysts and Effect on Catalytic Activity

Serra-Maia

Winkler

Murayama

et al. 2018

ACS Appl. Energy Mater.

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“…The catalytic activity of Pt in the decomposition of H 2 O 2 is known to also depend on the structural and/or surface chemical properties of the catalyst. ,,, Higher concentrations of surface oxygen correlate with enhanced H 2 O 2 decomposition rates, but a mechanistic understanding for this correlation has not yet been established. ,,, Higher H 2 O 2 decomposition rates also match with enhanced cold-working of platinum catalysts. This effect was initially attributed to an increase in structural dislocations , but was later ascribed to an enhancement of surface oxygen …”

Section: Introductionmentioning

confidence: 99%

Mechanism and Kinetics of Hydrogen Peroxide Decomposition on Platinum Nanocatalysts

Serra-Maia

Bellier

Chastka

et al. 2018

ACS Appl. Mater. Interfaces

113

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The decomposition of HO to HO and O catalyzed by platinum nanocatalysts controls the energy yield of several energy conversion technologies, such as hydrogen fuel cells. However, the reaction mechanism and rate-limiting step of this reaction have been unsolved for more than 100 years. We determined both the reaction mechanism and rate-limiting step by studying the effect of different reaction conditions, nanoparticle size, and surface composition on the rates of HO decomposition by three platinum nanocatalysts with average particle sizes of 3, 11, and 22 nm. Rate models indicate that the reaction pathway of HO decomposition is similar for all three nanocatalysts. Larger particle size correlates with lower activation energy and enhanced catalytic activity, explained by a smaller work function for larger platinum particles, which favors chemisorption of oxygen onto platinum to form Pt(O). Our experiments also showed that incorporation of oxygen at the nanocatalyst surface results in a faster reaction rate because the rate-limiting step is skipped in the first cycle of reaction. Taken together, these results indicate that the reaction proceeds in two cyclic steps and that step 1 is the rate-limiting step. Step 1: Pt + H O → H O + Pt( O). Step 2: Pt( O) + H O → Pt + O + H O. Overall: 2 H O → O + 2 H O. Establishing relationships between the properties of commercial nanocatalysts and their catalytic activity, as we have done here for platinum in the decomposition of HO, opens the possibility of improving the performance of nanocatalysts used in applications. This study also demonstrates the advantage of combining detailed characterization and systematic reactivity experiments to understand property-behavior relationships.

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Reactions of hydrogen peroxide on a silver electrode in alkaline solution

Merkulova

Zhutaeva

Shumilova

et al. 1973

Electrochimica Acta

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Surface heterogeneity of metals of the copper group in the catalytic decomposition of hydrogen peroxide

Cited by 10 publications

References 2 publications

Abundance and Speciation of Surface Oxygen on Nanosized Platinum Catalysts and Effect on Catalytic Activity

Abundance and Speciation of Surface Oxygen on Nanosized Platinum Catalysts and Effect on Catalytic Activity

Mechanism and Kinetics of Hydrogen Peroxide Decomposition on Platinum Nanocatalysts

Reactions of hydrogen peroxide on a silver electrode in alkaline solution

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