Nanoscale adhesion between Pt nanoparticles and carbon support and its influence on the durability of fuel cells

Dai

ACS Sustainable Chem. Eng.

et al. 2021

Carbon materials have been widely utilized as supports in different catalytic reactions; however, it has been rarely reported that carbon supports were used in the catalytic oxidation of volatile organic compounds because they have no catalytic activity and poor catalytic stability compared to metal supports. Herein, fabricating optimal carbon supports to facilitate the catalytic oxidation of benzene has become a great concern of research. A novel activated carbon (biomass−HCO) was prepared from different waste biomass via a three-stage route without the participation of harmful chemical reagents. The successful synthesis of C−O bonds and CO bonds through this method could greatly increase oxygen-enriched functional groups and defects of the biomass−HCO surface, which could effectively promote the nucleation and growth of platinum. Benzene oxidation reactions were performed to evaluate the activity of catalysts. The results demonstrated that Pt/biomass−HCO catalyst made the reaction temperature sharply decrease to 160 °C at T 90 . The 150 h on-stream reaction exhibited great thermal stability of Pt/biomass−HCO. The DFT calculations verified the strong interaction between Pt nanoparticles and carbon supports. Moreover, our demonstration of the superior benzene oxidation activity of Pt/ biomass−HCO catalysts revealed that it is feasible to utilize oxygen-enriched biomass carbon as catalytic supports toward the oxidation of volatile organic compounds.

Section: Resultsmentioning

confidence: 99%

Oxygen-Enriched Biomass-Activated Carbon Supported Platinum Nanoparticles as an Efficient and Durable Catalyst for Oxidation in Benzene

Dai

ACS Sustainable Chem. Eng.

et al. 2021

“…The excellent results could be explained by the strong interactions between the support and the Pd nanoparticles through surface functional groups. These groups also provided finer nanoparticles with better arrangements and, thus, increased the catalytic effectivity of the catalyst [ 37 , 38 ].…”

Section: Resultsmentioning

confidence: 99%

Development of Highly Efficient, Glassy Carbon Foam Supported, Palladium Catalysts for Hydrogenation of Nitrobenzene

et al. 2021

Glassy carbon foam (GCF) catalyst supports were synthesized from waste polyurethane elastomers by impregnating them in sucrose solution followed by pyrolysis and activation (AC) using N2 and CO2 gas. The palladium nanoparticles were formed from Pd(NO3)2. The formed palladium nanoparticles are highly dispersive because the mean diameters are 8.0 ± 4.3 (Pd/GCF), 7.6 ± 4.2 (Pd/GCF-AC1) and 4.4 ± 1.6 nm (Pd/GCF-AC2). Oxidative post-treatment by CO2 of the supports resulted in the formation of hydroxyl groups on the GCF surfaces, leading to a decrease in zeta potential. The decreased zeta potential increased the wettability of the GCF supports. This, and the interactions between –OH groups and Pd ions, decreased the particle size of palladium. The catalysts were tested in the hydrogenation of nitrobenzene. The non-treated, glassy-carbon-supported catalyst (Pd/GCF) resulted in a 99.2% aniline yield at 293 K and 50 bar hydrogen pressure, but the reaction was slightly slower than other catalysts. The catalysts on the post-treated (activated) supports showed higher catalytic activity and the rate of hydrogenation was higher. The maximum attained aniline selectivities were 99.0% (Pd/GCF-AC1) at 293 K and 98.0% (Pd/GCF-AC2) at 323 K.

“…After its invention in 1986, AFM quickly became a versatile surface probing technique for the investigation of various surface properties, including topography, − adhesion, , friction, , conductance, − magnetization, surface potential, and more. , One of the most widely used force detection mechanisms in AFM is the laser deflection method, in which a laser beam is reflected from the back of a cantilever and detected by a position-sensitive photodiode . From the position of the reflected beam, one can detect the bending of the cantilever perpendicular (normal force) and parallel (lateral force) to the surface plane.…”

Section: Operando Surface Science On Single Crystal Catalystsmentioning

confidence: 99%

“…40 In this design, the STM scanner was thermally isolated by a small molybdenum dome, through which only the tip can pass a 0.5 nm aperture to probe the catalyst sample surface; atomically resolved STM images could thereby be obtained in pressure up to 1 bar and elevated temperatures up to 700 K. It is also worthwhile to mention the "reactorSTM" design by Herbschleb et al, in which the STM scanner could be separated from the high-pressure reactor cell (0.5 cm 3 ) and remain in UHV. 41 The AP scanning tunneling microscope in this reactorSTM system could be operated from UHV to 6 bar and at temperatures up to 600 K. After its invention in 1986, 42 AFM quickly became a versatile surface probing technique for the investigation of various surface properties, including topography, 43−45 adhesion, 46,47 friction, 48,49 conductance, 50−52 magnetization, 53 surface potential, 54 and more. 55, 56 One of the most widely used force detection mechanisms in AFM is the laser deflection method, in which a laser beam is reflected from the back of a cantilever and detected by a position-sensitive photodiode.…”

mentioning

confidence: 99%

Operando Surface Characterization on Catalytic and Energy Materials from Single Crystals to Nanoparticles

Choi

Kim

et al. 2020

ACS Nano

Self Cite

Modern surface science faces two major challenges, a materials gap and a pressure gap. While studies on single crystal surface in ultrahigh vacuum have uncovered the atomic and electronic structures of the surface, the materials and environmental conditions of commercial catalysis are much more complicated, both in the structure of the materials and in the accessible pressure range of analysis instruments. Model systems and operando surface techniques have been developed to bridge these gaps. In this Review, we highlight the current trends in the development of the surface characterization techniques and methodologies in more realistic environments, with emphasis on recent research efforts at the Korea Advanced Institute of Science and Technology. We show principles and applications of the microscopic and spectroscopic surface techniques at ambient pressure that were used for the characterization of atomic structure, electronic structure, charge transport, and the mechanical properties of catalytic and energy materials. Ambient pressure scanning tunneling microscopy and X-ray photoelectron spectroscopy allow us to observe the surface restructuring that occurs during oxidation, reduction, and catalytic processes. In addition, we introduce the ambient pressure atomic force microscopy that revealed the morphological, mechanical, and charge transport properties that occur during the catalytic and energy conversion processes. Hot electron detection enables the monitoring of catalytic reactions and electronic excitations on the surface. Overall, the information on the nature of catalytic reactions obtained with operando spectroscopic and microscopic techniques may bring breakthroughs in some of the global energy and environmental problems the world is facing.