Revolutionizing Fuel Cell Catalysts: Enhanced Durability and Performance with Platinum-Modified Tungsten Oxide Support

Breakthrough Study Utilizes Atomic Layer Deposition and Ar Plasma Treatment for Highly Robust Anode Catalysts in Polymer Electrolyte Membrane Fuel Cells

Key Findings:

1. Tungsten oxide (WO3) supported catalysts, enhanced through Ar plasma surface treatment and Pt nanoparticle deposition using atomic layer deposition (ALD), demonstrated significantly improved durability in diverse operating conditions compared to commercial Pt/C catalysts.

2. The use of WO3 as a catalyst support material, coupled with ALD-based Pt nanoparticle deposition, offers a promising approach for developing high-performance anode catalysts for polymer electrolyte membrane fuel cells (PEMFCs) with enhanced stability and performance.

In an article titled "Atomic layer deposited platinum on tungsten oxide support as high-performance hybrid catalysts for polymer electrolyte membrane fuel cells" Korean researchers discuss the development of a robust anode catalyst for polymer electrolyte membrane fuel cells (PEMFCs). The researchers aimed to address the performance degradation and carbon support corrosion issues commonly observed in PEMFCs under harsh operating conditions.

Graphical abstract

The study focused on using tungsten oxide (WO3) as a catalyst support material due to its ability to provide additional hydrogen ions and electrons through the decomposition of tungsten bronze (HxWO3) formed by the hydrogen spillover effect. The presence of HxWO3 also helped stabilize the cell potential by scavenging oxygen that infiltrates into the anode during start-up and shut-down situations. However, the low electrical conductivity of metal oxides can lead to initial performance degradation.

To overcome this limitation, the researchers performed Ar plasma surface treatment on the WO3 layer to enhance its electrical conductivity. This treatment, known as P-WO3, increased the density of electrons, enabling n-doped conduction. Next, platinum (Pt) nanoparticles were deposited on the P-WO3 support using atomic layer deposition (ALD). ALD allowed for the controlled deposition of Pt at the nanoscale, maximizing the catalytic activity with a minimal amount of precious metal.

The resulting Pt/P-WO3 catalyst exhibited significantly enhanced durability compared to commercial Pt/C catalysts under diverse operating conditions. It demonstrated improved performance and acted as a reversal-tolerant anode catalyst. The study highlights the potential of using WO3 as a support material and the effectiveness of the proposed fabrication method in developing high-performance catalysts for PEMFCs.

Overall, the article presents a novel approach to address the challenges associated with catalyst performance and carbon support corrosion in PEMFCs. By utilizing WO3 as a support material and incorporating Pt nanoparticles through ALD, the researchers achieved an improved and durable anode catalyst for PEMFCs.

The academic institutions behind the article are:

1. Department of Automotive Convergence, Korea University, Republic of Korea.

2. School of Mechanical Engineering, Korea University, Republic of Korea.

Source: Atomic layer deposited platinum on tungsten oxide support as high performance hybrid catalysts for polymer electrolyte membrane fuel cells - ScienceDirect

Forge Nano and Argonne improve yield in propylene manufacturing by ALD coating

Propylene, a precursor for commodity chemicals and plastics, is produced by propane dehydrogenation (PDH). In a PDH process, propane is selectively dehydrogenated to propylene. Production capacity via PDH is slated to grow rapidly over the next several years. The single feed/single product feature is one of the most attractive aspects of PDH, especially for propylene derivative producers looking to back-integrate for a secure and cost-effective source of propylene (IHS Markit Report LINK). 

Despite its simple chemistry, industrial implementation of PDH is very complicated owing to side reactions such as: 

• deep dehydrogenation
• hydrogenolysis
• cracking
• polymerization
• coke formation.

According to a recent publication by Forge Nano and Argonne National Lab, an increase in PDH yield via added catalyst activity, lifetime, or selectivity represents significant energy and economic savings. 

The researchers has demonstrated that by using Pt dispersed on Al2O3 extrudate supports as a commercially relevant model system and by using atomic layer deposition (ALD) metal oxide overcoats, the metal-active sites can be tailored to increase PDH yield and selectivity. 

In the study they investigate the interplay of Pt loading, ALD overcoat thickness, and Al2O3 support surface area on PDH activity, selectivity, and catalyst stability. 

They were able to show that applying a 6–8 Å thick layer of Al2O3 on low-surface area Al2O3 supports of ∼90 m2/g surface area yields the optimal combination of stability and activity, while increasing propylene selectivity from 91 to 96%. Please find further details in the paper linked below.

Catalyst preparation method, Graphical abstract (https://doi.org/10.1021/acscatal.0c03391)

Atomic Layer Deposition Overcoating Improves Catalyst Selectivity and Longevity in Propane Dehydrogenation
Zheng Lu, Ryon W. Tracy, M. Leigh Abrams, Natalie L. Nicholls, Paul T. Barger, Tao Li, Peter C. Stair,
Arrelaine A. Dameron, Christopher P. Nicholas, and Christopher L. Marshall

ACS Catal. 2020, 10, XXX, 13957–13967
Publication Date:November 16, 2020

https://doi.org/10.1021/acscatal.0c03391

Atomic layer deposited Pt-Ru dual-metal dimers and identifying their active sites for hydrogen evolution reaction

Here is an interesting article on how to nucleate ALD on the rather inert CNT surface, or rather nitrogen doped CNTs. It seems to be straight forward:

1. NCNT synthesis by ultrasonic spray pyrolysis according with imidazole as carbon and nitrogen source, and ferrocene as the catalyst precursor.

2.  Thermal ALD in a CNT Savannah 100 using MeCpPtMe₃ and bis(ethylcyclopentadienyl)ruthenium respectively. 

Atomic layer deposited Pt-Ru dual-metal dimers and identifying their active sites for hydrogen evolution reaction
Zhang, L., Si, R., Liu, H. et al. Nat Commun 10, 4936 (2019) doi:10.1038/s41467-019-12887-y

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License

Single atom catalysts exhibit particularly high catalytic activities in contrast to regular nanomaterial-based catalysts. Until recently, research has been mostly focused on single atom catalysts, and it remains a great challenge to synthesize bimetallic dimer structures. Herein, we successfully prepare high-quality one-to-one A-B bimetallic dimer structures (Pt-Ru dimers) through an atomic layer deposition (ALD) process. The Pt-Ru dimers show much higher hydrogen evolution activity (more than 50 times) and excellent stability compared to commercial Pt/C catalysts. X-ray absorption spectroscopy indicates that the Pt-Ru dimers structure model contains one Pt-Ru bonding configuration. First principle calculations reveal that the Pt-Ru dimer generates a synergy effect by modulating the electronic structure, which results in the enhanced hydrogen evolution activity. This work paves the way for the rational design of bimetallic dimers with good activity and stability, which have a great potential to be applied in various catalytic reactions. 

Schematic illustration of ALD synthesis of Pt–Ru dimers on nitrogen-doped carbon nanotubes (NCNTs). Firstly, the Pt single atoms were deposited by using MeCpPtMe₃ as the precursor. Then the Pt–Ru dimers were prepared by selective deposition of Ru atoms on Pt single atoms. Gray: C, Blue: N, yellow: Pt, red: Ru

Encapsulation of homogeneous catalysts in mesoporous materials by diffusion limited ALD

Researches from the Chinese Academy of Sciences demonstrate ALD encapsulation of metal complexes into nanochannels of mesoporous materials is. The pore size of the hollow plug is precisely controlled on the sub-nanometer scale by the number of ALD cycles to fit various metal complexes with different molecular sizes. They claim that this ALD-assisted encapsulation method can be extended to the encapsulation of other homogeneous catalysts into different mesoporous materials for various heterogeneous reactions. Please find the paper below!

Beautiful TEM analysis of carbon nanofibers that have beencoated with 400 cycles TiO2 (supporting information, LINK)

Reference: Zhang, S., Zhang, B., Liang, H., Liu, Y., Qiao, Y. and Qin, Y. (2017), Encapsulation of Homogeneous Catalysts in Mesoporous Materials Using Diffusion-Limited Atomic Layer Deposition. Angew. Chem. Int. Ed.. doi: 10.1002/anie.201712010

Encapsulation of Homogeneous Catalysts in Meso#PorousMaterials Using Diffusion-Limited Atomic Layer Deposition (Qin) https://t.co/t7RedVRncj pic.twitter.com/ELY1Xj3cyC

— Angewandte Chemie (@angew_chem) December 27, 2017

Picture from Tweet above

The Korea Research Institute of Chemical Technology develops ALD MoS2 catalyst for hydrogen fuel

The Korea Research Institute of Chemical Technology (KRICT) has developed a core electro-catalyst design technology that can significantly improve electrochemical fuel reaction which produces hydrogen fuel.

The research team led by Dr. Kim Hyung-joo from CO2 energy vector research division at the KRICT announced on September 27 that it succeeded in developing the technology that can activate fuel reaction by changing the surface of molybdenum disulfide (MoS2) which is cheaper than white gold.

Source: BusinessKorea LINK

New promising ALD catalyst for CO2 splitting

Scientists from École polytechnique fédérale de Lausanne (EPFL) in Switzerland has reported a low cost system to split carbon dioxide to carbon monoxide and oxygen using an ALD tin oxide catalyst on copper oxide nanowires. The devis is working at a rather efficiency of 13.4%, which opens up new paths to get rid of the man made CO2 that is currently heating up our planet and causing extreme weather conditions everywhere  - believe it or not.

The research comes out of the famous laboratory of Prof. Michael Grätzel at EPFL, one of the worlds top 10 most cited chemists and most certainly the most cited chemist from Dorfchemnitz in Saxony, Germany. One of his most famous invention is the so called Gräzel cell - a dye-sensitized solar cell, which is a low-cost version of thin film solar cells and he was awarded the 2010 Millennium Technology Prize for this invention.

Michael Grätzel (born 11 May 1944, in Dorfchemnitz, Saxony, Germany) is a professor at the École Polytechnique Fédérale de Lausanne where he directs the Laboratory of Photonics and Interfaces [Wikipedia].

Using Earth-abundant materials, EPFL scientists have built the first low-cost system for splitting CO2 into CO, a reaction necessary for turning renewable energy into fuel.

The future of clean energy depends on our ability to efficiently store energy from renewable sources and use it later. A popular way to do this is to electrolyze carbon dioxide to carbon monoxide, which is then mixed with hydrogen to produce liquid hydrocarbons like gasoline or kerosene that can be used as fuel. However, we currently lack efficient and Earth-abundant catalysts for the initial splitting of CO2 into CO and oxygen, which makes the move into renewable energy expensive and prohibitive. EPFL scientists have now developed an Earth-abundant catalyst based on copper-oxide nanowires modified with tin oxide. The system can split CO2 with an efficiency of 13.4%. The work is published in Nature Energy, and can help worldwide efforts to synthetically produce carbon-based fuels from CO2 and water.

Read more at: https://phys.org/news/2017-06-low-cost-carbon-dioxide.html#jCpv

Using Earth-abundant materials, EPFL scientists have built the first low-cost system for splitting CO2 into CO, a reaction necessary for turning renewable energy into fuel.

The future of clean energy depends on our ability to efficiently store energy from renewable sources and use it later. A popular way to do this is to electrolyze carbon dioxide to carbon monoxide, which is then mixed with hydrogen to produce liquid hydrocarbons like gasoline or kerosene that can be used as fuel. However, we currently lack efficient and Earth-abundant catalysts for the initial splitting of CO2 into CO and oxygen, which makes the move into renewable energy expensive and prohibitive. EPFL scientists have now developed an Earth-abundant catalyst based on copper-oxide nanowires modified with tin oxide. The system can split CO2 with an efficiency of 13.4%. The work is published in Nature Energy, and can help worldwide efforts to synthetically produce carbon-based fuels from CO2 and water.

Read more at: https://phys.org/news/2017-06-low-cost-carbon-dioxide.html#jCp

Using Earth-abundant materials, EPFL scientists have built the first low-cost system for splitting CO2 into CO, a reaction necessary for turning renewable energy into fuel.

The future of clean energy depends on our ability to efficiently store energy from renewable sources and use it later. A popular way to do this is to electrolyze carbon dioxide to carbon monoxide, which is then mixed with hydrogen to produce liquid hydrocarbons like gasoline or kerosene that can be used as fuel. However, we currently lack efficient and Earth-abundant catalysts for the initial splitting of CO2 into CO and oxygen, which makes the move into renewable energy expensive and prohibitive. EPFL scientists have now developed an Earth-abundant catalyst based on copper-oxide nanowires modified with tin oxide. The system can split CO2 with an efficiency of 13.4%. The work is published in Nature Energy, and can help worldwide efforts to synthetically produce carbon-based fuels from CO2 and water.

Read more at: https://phys.org/news/2017-06-low-cost-carbon-dioxide.html#jCp

Using Earth-abundant materials, EPFL scientists have built the first low-cost system for splitting CO2 into CO, a reaction necessary for turning renewable energy into fuel.

The future of clean energy depends on our ability to efficiently store energy from renewable sources and use it later. A popular way to do this is to electrolyze carbon dioxide to carbon monoxide, which is then mixed with hydrogen to produce liquid hydrocarbons like gasoline or kerosene that can be used as fuel. However, we currently lack efficient and Earth-abundant catalysts for the initial splitting of CO2 into CO and oxygen, which makes the move into renewable energy expensive and prohibitive. EPFL scientists have now developed an Earth-abundant catalyst based on copper-oxide nanowires modified with tin oxide. The system can split CO2 with an efficiency of 13.4%. The work is published in Nature Energy, and can help worldwide efforts to synthetically produce carbon-based fuels from CO2 and water.

Read more at: https://phys.org/news/2017-06-low-cost-carbon-dioxide.html#jCp

Using Earth-abundant materials, EPFL scientists have built the first low-cost system for splitting CO2 into CO, a reaction necessary for turning renewable energy into fuel.

The future of clean energy depends on our ability to efficiently store energy from renewable sources and use it later. A popular way to do this is to electrolyze carbon dioxide to carbon monoxide, which is then mixed with hydrogen to produce liquid hydrocarbons like gasoline or kerosene that can be used as fuel. However, we currently lack efficient and Earth-abundant catalysts for the initial splitting of CO2 into CO and oxygen, which makes the move into renewable energy expensive and prohibitive. EPFL scientists have now developed an Earth-abundant catalyst based on copper-oxide nanowires modified with tin oxide. The system can split CO2 with an efficiency of 13.4%. The work is published in Nature Energy, and can help worldwide efforts to synthetically produce carbon-based fuels from CO2 and water.

Read more at: https://phys.org/news/2017-06-low-cost-carbon-dioxide.html#jCp

Below the abstract and the link to the Nature Energy publication

Solar conversion of CO2 to CO using Earth-abundant electrocatalysts prepared by atomic layer modification of CuO

Marcel Schreier, Florent Héroguel, Ludmilla Steier, Shahzada Ahmad, Jeremy S. Luterbacher, Matthew T. Mayer, Jingshan Luo & Michael Grätzel

Nature Energy 2, Article number: 17087 (2017) doi:10.1038/nenergy.2017.87

Abstract: The solar-driven electrochemical reduction of CO2 to fuels and chemicals provides a promising way for closing the anthropogenic carbon cycle. However, the lack of selective and Earth-abundant catalysts able to achieve the desired transformation reactions in an aqueous matrix presents a substantial impediment as of today. Here we introduce atomic layer deposition of SnO2 on CuO nanowires as a means for changing the wide product distribution of CuO-derived CO2 reduction electrocatalysts to yield predominantly CO. The activity of this catalyst towards oxygen evolution enables us to use it both as the cathode and anode for complete CO2 electrolysis. In the resulting device, the electrodes are separated by a bipolar membrane, allowing each half-reaction to run in its optimal electrolyte environment. Using a GaInP/GaInAs/Ge photovoltaic we achieve the solar-driven splitting of CO2 into CO and oxygen with a bifunctional, sustainable and all Earth-abundant system at an efficiency of 13.4%

Solar conversion of CO2 by ALD modified CuO catalyst

Chemistry World reports that Earth abundant materials can be nano-engineered to make best use of increasingly abundant solar power. Now researchers in Switzerland have developed a catalyst, made entirely from earth abundant materials, that allows solar-generated electricity to reduce the environmental pollutant carbon dioxide to the valuable chemical feedstock carbon monoxide.

In the new research, Luo and colleagues used atomic layer deposition – a modified form of chemical vapour deposition allowing deposition of single, continuous atomic layers – to cover copper oxide nanowires with a very thin layer of tin oxide. Please find more detailed information and sources below

Full story:  LINK

Reference:
M Schreier et al, Nat. Energy, 2017, 2, 17087 (DOI: 10.1038/nenergy.2017.87)

Abstract: The solar-driven electrochemical reduction of CO2 to fuels and chemicals provides a promising way for closing the anthropogenic carbon cycle. However, the lack of selective and Earth-abundant catalysts able to achieve the desired transformation reactions in an aqueous matrix presents a substantial impediment as of today. Here we introduce atomic layer deposition of SnO2 on CuO nanowires as a means for changing the wide product distribution of CuO-derived CO2 reduction electrocatalysts to yield predominantly CO. The activity of this catalyst towards oxygen evolution enables us to use it both as the cathode and anode for complete CO2 electrolysis. In the resulting device, the electrodes are separated by a bipolar membrane, allowing each half-reaction to run in its optimal electrolyte environment. Using a GaInP/GaInAs/Ge photovoltaic we achieve the solar-driven splitting of CO2 into CO and oxygen with a bifunctional, sustainable and all Earth-abundant system at an efficiency of 13.4%.

Argonne scientists uses ALD vanadium as a catalyst for hydrogenation

Argonne researcher Max Delferro enhanced a process for catalytic activity of  vanadium for hydrogenation. The advantage is that if we can make vanadium that is an abundant metal catalytically active there are huge cost savings compared to using noble metals like Platinum or Paladium.

“Getting single-atom vanadium into this special configuration on metal oxide surfaces is not easy,” Delferro said. “It requires the use of special synthetic techniques such as surface organometallic chemistry and atomic layer deposition. However, if we can make vanadium or another abundant metal as catalytically active as the noble metals, we can create dramatic cost savings in these very common and commercially important catalytic processes.” Delferro said in a press release by Argonne (LINK).

Publication: “Isolated, Well-Defined Organovanadium(III) on Silica: Single-Site Catalyst for Hydrogenation of Alkenes and Alkynes,” Chemical Communications

Argonne scientists make vanadium into a useful catalyst for hydrogenation https://t.co/CGSnHh0TRB pic.twitter.com/1nHLuOICOw

— Science (@scienmag) May 26, 2017

KAUST technology extracts more from wastewater using ALD catalyst

KAUST present a novel electrocatalytic and microfiltration polymeric hollow fiber using ALD of platinum that is fabricated for simultaneous recovery of energy (H2) and clean fresh water from wastewater, hence addressing two grand challenges facing society in the current century (i.e., providing adequate supplies of clean fresh water and energy as the world's population increases).

More information: Krishna P. Katuri et al. A Microfiltration Polymer-Based Hollow-Fiber Cathode as a Promising Advanced Material for Simultaneous Recovery of Energy and Water, Advanced Materials (2016). DOI: 10.1002/adma.201603074

Read more at: https://phys.org/news/2017-01-wastewater.html#jCp

The results have been published in Adv. Mater., DOI: 10.1002/adma.201603074 and according to the supporting information the catalyst deposition by ALD on the outer surface of a POD hollow fiber membranes and was carried out on Oxford Instrument ALD system FlexAL

Read more at: https://phys.org/news/2017-01-wastewater.html#jCp

Fresh water scarcity and energy security are two critical global challenges facing us today. Researchers at KAUST have now created an advanced material that can address both problems simultaneously by producing clean water and hydrogen from wastewater.

ALD of Pd Nanoparticles on TiO2 Nanotubes for Ethanol Electrooxidation

Direct Ethanol Fuel Cells DEFCs are considered one of the promising renewable energy sources, as they can produce electrical energy directly from the ethanol electrooxidation reaction. The efficiency of ethanol electrooxidation is a big question from research point of view. Here French and Canadian researchers show how ALD Pd nano particles grown in anodic titanium oxide nanotubes can be used for Ethanol Electrooxidation.

Atomic Layer Deposition of Pd Nanoparticles on TiO2 Nanotubes for Ethanol Electrooxidation: Synthesis and Electrochemical Properties

Loïc Assaud, Nicolas Brazeau, Maïssa K. S. Barr, Margrit Hanbücken, Spyridon Ntais, Elena A. Baranova, and Lionel Santinacc

ACS Appl. Mater. Interfaces, Article ASAP
DOI: 10.1021/acsami.5b06056

 

 

Palladium nanoparticles are grown on TiO₂ nanotubes by atomic layer deposition (ALD), and the resulting three-dimensional nanostructured catalysts are studied for ethanol electrooxidation in alkaline media. The morphology, the crystal structure, and the chemical composition of the Pd particles are fully characterized using scanning and transmission electron microscopies, X-ray diffraction, and X-ray photoelectron spectroscopy. The characterization revealed that the deposition proceeds onto the entire surface of the TiO₂ nanotubes leading to the formation of well-defined and highly dispersed Pd nanoparticles. The electrooxidation of ethanol on Pd clusters deposited on TiO₂ nanotubes shows not only a direct correlation between the catalytic activity and the particle size but also a steep increase of the response due to the enhancement of the metal–support interaction when the crystal structure of the TiO₂ nanotubes is modified by annealing at 450 °C in air.

GEMStar-CAT Dual™ Dual Reactor ALD and Catalyst Synthesis System by Arradiance

US ALD company Arradiance has released a new version of their GEMStar series of ALD tools -The GEMStar-CAT Dual™ Dual Reactor ALD and Catalyst Synthesis System. The custom GEMStar-DUAL CatalystTM System developed in partnership with the Chemical Sciences and Engineering Division of Argonne National Laboratory has unique capabilities. Arradiance used its skill combining Atomic Layer Deposition, System Design and Controls to produce a system that is unparalleled for Catalyst synthesis research

 

 

 Full specs and details can be downloaded in here and a publication is given below:

Catalyst synthesis and evaluation using an integrated atomic layer deposition synthesis–catalysis testing tool

Jeffrey Camacho-Bunquin, Heng Shou, Payoli Aich, David R. Beaulieu, Helmut Klotzsch, Stephen Bachman, Christopher L. Marshall, Adam Hock, and Peter Stair

(Received 24 June 2015; accepted 4 August 2015; published online 24 August 2015)

An integrated atomic layer deposition synthesis-catalysis (I-ALD-CAT) tool was developed. It combines an ALD manifold in-line with a plug-flow reactor system for the synthesis of supported catalytic materials by ALD and immediate evaluation of catalyst reactivity using gas-phase probe reactions. The I-ALD-CAT delivery system consists of 12 different metal ALD precursor channels, 4 oxidizing or reducing agents, and 4 catalytic reaction feeds to either of the two plug-flow reactors. The system can employ reactor pressures and temperatures in the range of 10−3 to 1 bar and 300–1000 K, respectively. The instrument is also equipped with a gas chromatograph and a mass spectrometer unit for the detection and quantification of volatile species from ALD and catalytic reactions. In this report, we demonstrate the use of the I-ALD-CAT tool for the synthesis of platinum active sites and Al2O3 overcoats, and evaluation of catalyst propylene hydrogenation activity. © 2015 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4928614]

ALD of single atom Pd on grapheme using a Arradiance Benchtop reactor

Here is an interesting report on the fabrication of single-atom Pd catalyst on graphene using ALD by researchers in Hefei, China. Pd ALD was carried out on a GEMSTAR-6TM Benchtop ALD from Arradiance at 150 °C using palladium hexafluoroacetylacetate (Pd(hfac)2) and formalin (37% HCHO and 15% CH3OH in aqueous solution).

Single-Atom Pd1/Graphene Catalyst Achieved by Atomic Layer Deposition: Remarkable Performance in Selective Hydrogenation of 1,3-Butadiene

Huan Yan, Hao Cheng, Hong Yi, Yue Lin, Tao Yao, Chunlei Wang, Junjie Li, Shiqiang Wei, and Junling Lu

Journal of the American Chemical Society

DOI: 10.1021/jacs.5b06485

We reported that atomically dispersed Pd on graphene can be fabricated using the atomic layer deposition technique. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy both confirmed that isolated Pd single atoms dominantly existed on the graphene support. In selective hydrogenation of 1,3-butadiene, the single-atom Pd1/graphene catalyst showed about 100% butenes selectivity at 95% conversion at a mild reaction condition of about 50 °C, which is likely due to the changes of 1,3-butadiene adsorption mode and enhanced steric effect on the isolated Pd atoms. More importantly, excellent durability against deactivation via either aggregation of metal atoms or carbonaceous deposits during a total 100 h of reaction time on stream was achieved. Therefore, the single-atom catalysts may open up more opportunities to optimize the activity, selectivity, and durability in selective hydrogenation reactions.

Ultra-Thin Hollow Nanocages Could Reduce Platinum Use in Fuel Cell Electrodes

As reported by Georgia Tech : A new fabrication technique that produces platinum hollow nanocages with ultra-thin walls could dramatically reduce the amount of the costly metal needed to provide catalytic activity in such applications as fuel cells.

The technique uses a solution-based method for producing atomic-scale layers of platinum to create hollow, porous structures that can generate catalytic activity both inside and outside the nanocages. The layers are grown on palladium nanocrystal templates, and then the palladium is etched away to leave behind nanocages approximately 20 nanometers in diameter, with between three and six atom-thin layers of platinum.

Use of these nanocage structures in fuel cell electrodes could increase the utilization efficiency of the platinum by a factor of as much as seven, potentially changing the economic viability of the fuel cells.

“We can get the catalytic activity we need by using only a small fraction of the platinum that had been required before,” said Younan Xia, a professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. Xia also holds joint faculty appointments in the School of Chemistry and Biochemistry and the School of Chemical and Biomolecular Engineering at Georgia Tech. “We have made hollow nanocages of platinum with walls as thin as a few atomic layers because we don’t want to waste any material in the bulk that does not contribute to the catalytic activity.”

The research – which also involved researchers at the University of Wisconsin-Madison, Oak Ridge National Laboratory, Arizona State University and Xiamen University in China – was scheduled to be reported in the July 24 issue of the journal Science.

Full story here : http://www.newswise.com/articles/ultra-thin-hollow-nanocages-could-reduce-platinum-use-in-fuel-cell-electrodes

Catalyst Design with Atomic Layer Deposition

A new ALD review on catalyst design from University of Wisconsin−Madison, Argonne National Laboratory and Northwestern University:

Catalyst Design with Atomic Layer Deposition
Brandon J. O’Neill, David H. K. Jackson, Jechan Lee, Christian Canlas, Peter C. Stair, Christopher L. Marshall, Jeffrey W. Elam, Thomas F. Kuech, James A. Dumesic, and George W. Huber

ACS Catal., 2015, 5, pp 1804–1825
DOI: 10.1021/cs501862h
Publication Date (Web): February 6, 2015

Atomic layer deposition (ALD) has emerged as an interesting tool for the atomically precise design and synthesis of catalytic materials. Herein, we discuss examples in which the atomic precision has been used to elucidate reaction mechanisms and catalyst structure–property relationships by creating materials with a controlled distribution of size, composition, and active site. We highlight ways ALD has been utilized to design catalysts with improved activity, selectivity, and stability under a variety of conditions (e.g., high temperature, gas and liquid phase, and corrosive environments). In addition, due to the flexibility and control of structure and composition, ALD can create myriad catalytic structures (e.g., high surface area oxides, metal nanoparticles, bimetallic nanoparticles, bifunctional catalysts, controlled microenvironments, etc.) that consequently possess applicability for a wide range of chemical reactions (e.g., CO2 conversion, electrocatalysis, photocatalytic and thermal water splitting, methane conversion, ethane and propane dehydrogenation, and biomass conversion). Finally, the outlook for ALD-derived catalytic materials is discussed, with emphasis on the pending challenges as well as areas of significant potential for building scientific insight and achieving practical impacts.