Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International

Wikipedia Affiliate Button

Home > Press > Rice U. lab adds porous envelope to aluminum plasmonics: Scientists marry gas-trapping framework to light-powered nanocatalysts

A graphic illustrating the synthesis method that begins with oxide-covered aluminum nanocrystals (top left) and ends with the nanocrystal encased in metal-organic framework (MOF). The MOF self-assembles around the particle when the oxide partially dissolves, releasing aluminum ions that bind with organic linkers to form a 3D framework. (Image courtesy of LANP/Rice University)

CREDIT
Image courtesy of LANP/Rice University
A graphic illustrating the synthesis method that begins with oxide-covered aluminum nanocrystals (top left) and ends with the nanocrystal encased in metal-organic framework (MOF). The MOF self-assembles around the particle when the oxide partially dissolves, releasing aluminum ions that bind with organic linkers to form a 3D framework. (Image courtesy of LANP/Rice University) CREDIT Image courtesy of LANP/Rice University

Abstract:
When Rice University chemist and engineer Hossein Robatjazi set out to marry a molecular sieve called MOF to a plasmonic aluminum nanoparticle two years ago, he never imagined the key would be the same process nature uses to petrify wood.

Rice U. lab adds porous envelope to aluminum plasmonics: Scientists marry gas-trapping framework to light-powered nanocatalysts

Houston, TX | Posted on February 10th, 2019

In a new paper online this week in the journal Science Advances, Robatjazi and co-authors with Rice's Laboratory for Nanophotonics (LANP) describe how pseudomorphic replacement, the same chemical process that turns a tree to stone, aided their synthesis of the first metal-organic framework (MOF) around light-powered aluminum nanocatalysts.

Catalysts are materials that speed up chemical reactions without reacting themselves, and they're used in the manufacture of most commercially produced chemicals. Because most industrial catalysts work best at high temperature or high pressure or both, they also come with an enormous energy burden. The combination of MOFs and plasmonic aluminum creates a new avenue for designing greener catalysts that use solar energy and are made from the most abundant metal in Earth's crust.

In the study, Robatjazi, LANP Director Naomi Halas and colleagues performed a proof-of-principle demonstration of a process known as the reverse water-gas shift reaction at ambient temperature and pressure under laboratory conditions that simulated sunlight. The reaction transforms carbon dioxide (CO2) and hydrogen gas into carbon monoxide -- a feedstock for chemical manufacturing -- and water.

"This is the first example showing that you can combine MOF and aluminum particles to do this reaction with light," said Robatjazi, a graduate student at LANP, the Rice lab that has pioneered plasmonic technologies for applications as diverse as cancer diagnosis and treatment, MRI contrast agents and solar water distillation.

Plasmons are waves of electrons that slosh across the surface of tiny metal nanoparticles, and by varying a plasmonic nanoparticle's shape and size, LANP scientists can tune it to interact with and harvest energy from light. In previous research, LANP demonstrated copper nanocatalysts for making clean-burning hydrogen from ammonia, and aluminum-based antenna-reactors for making ethylene, the chemical feedstock for polyethylene, the world's most common plastic.

Halas said the latest work with MOFs is important for several reasons.

"We've shown that growing MOFs around aluminum nanocrystals enhances the photocatalytic activity of the aluminum particles and also provides us a new way of controlling the size, and therefore the plasmonic characteristics, of the particles themselves," Halas said. "Finally, we've shown that the same basic method works for making different kinds of MOFs."

MOFs are three-dimensional structures that self-assemble when metal ions interact with organic molecules called linkers. The structures are highly porous, like a sponge or Swiss cheese. Just a gram of some MOFs have a surface area larger than a football field, and by varying the type of metal, the linker and reaction conditions, chemists can design MOFs with different structures, pore sizes and functions, like trapping specific molecules. More than 20,000 kinds of MOFs have been made.

In Robatjazi's initial experiments, he attempted to grow MIL-53, a well-studied MOF that's noted for its CO2-trapping ability. He tried synthesis methods that had worked for growing MOFs around gold particles, but they failed for aluminum, and Robatjazi suspected aluminum oxide was to blame.

Unlike gold, aluminum is highly reactive with oxygen, and every aluminum nanoparticle instantly becomes covered with a thin 2- to 4-nanometer sheen of aluminum oxide the moment it comes in contact with air.

"It's amorphous," Robatjazi said. "It's not like a flat surface with a well-defined crystallinity. It's like a bumpy road, and the MOF crystals could not make a structure on that surface."

In looking at the chemical literature, Robatjazi got the idea to let pseudomorphic mineral replacement do the work of both preparing the surface of the particles to accept MOFs and providing the metal building blocks for MOFs.

"We learned from Mother Nature, and we basically use the same strategy because aluminum oxide is a mineral," he said. "Normally for MOFs, we mix a metal ion with the organic linker, and in this case we eliminated the metal ion and instead dissolved the aluminum oxide and used the aluminum ions from that reaction as metal components of our MOF."

By varying the reaction conditions, Robatjazi found he could control how much of the aluminum surface he etched away, and thus control the final size -- and plasmonic properties -- of the plasmonic particle inside. For MIL-53, the CO2-trapping MOF, he showed that the catalytic activity of the plasmonic aluminum nanocrystal increased substantially when the MOF was in place.

Finally, he demonstrated he could use the same etching method with different linkers, making MOFs with varied pore sizes and other properties, including a hydrophilic variety that kept water away from the aluminum particle within.

"We're exploring avenues to tune the characteristics of aluminum-MOF structures, either by synthetic variation or post-synthesis modification," Halas said. "That flexibility could open a range of opportunities for scaling up plasmon-mediated chemical reactions that are both less expensive for industry and better for the environment."

###

Halas is Rice's Stanley C. Moore Professor of Electrical and Computer Engineering and professor of chemistry, bioengineering, physics and astronomy, and materials science and nanoengineering. She also is director of Rice's Smalley-Curl Institute.

Robatjazi is a doctoral student in Rice's Department of Electrical and Computer Engineering.

Study co-authors include Daniel Weinberg, Dayne Swearer, Christian Jacobson, Ming Zhang, Shu Tian, Linan Zhou and Peter Nordlander, all of Rice. The research was supported by the Welch Foundation, the Air Force Office of Scientific Research, the Defense Threat Reduction Agency, the National Science Foundation and the Rice Department of Chemistry.

####

About Rice University
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,962 undergraduates and 3,027 graduate students, Rice's undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 2 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.com/RiceUniversityoverview .

Follow Rice News and Media Relations via Twitter @RiceUNews.

For more information, please click here

Contacts:
Jade Boyd

713-348-6778

Copyright © Rice University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

RELATED JOURNAL ARTICLE:

Related News Press

News and information

A light-activated remote control for cells April 17th, 2019

NEXUS 2019: Global Summit on Energy Materials and Green Nanotechnology April 16th, 2019

Arrowhead Pharmaceuticals Receives FDA Clearance to Begin Phase 2/3 Study of ARO-AAT for Treatment of Alpha-1 Liver Disease April 15th, 2019

New microscopy method provides more details about nanocomposites April 12th, 2019

Chemistry

Russian physicists obtained data on particles self-organization in ultracold dusty plasma March 29th, 2019

Chemicals induce dipoles to damp plasmons: Rice University-led study finds molecules alter gold nanoparticles' electronic properties March 22nd, 2019

Converting biomass by applying mechanical force Nanoscientists discover new mechanism to cleave cellulose effectively and in an environmentally friendly way March 15th, 2019

New blueprint for understanding, predicting and optimizing complex nanoparticles: Guidelines have the potential to transform the fields of optoelectronics, bio-imaging and energy harvesting March 1st, 2019

Plasmonics

Chemicals induce dipoles to damp plasmons: Rice University-led study finds molecules alter gold nanoparticles' electronic properties March 22nd, 2019

Govt.-Legislation/Regulation/Funding/Policy

A light-activated remote control for cells April 17th, 2019

Arrowhead Pharmaceuticals Receives FDA Clearance to Begin Phase 2/3 Study of ARO-AAT for Treatment of Alpha-1 Liver Disease April 15th, 2019

New microscopy method provides more details about nanocomposites April 12th, 2019

'Nanobodies' from alpacas could help bring CAR T-cell therapy to solid tumors: Unusually small antibodies, targeted to the tumor micro-environment, curb melanoma and colon cancer in mouse models April 11th, 2019

Possible Futures

A light-activated remote control for cells April 17th, 2019

Oregon scientists drill into white graphene to create artificial atoms: Patterned on a microchip and working in ambient conditions, the atoms could lead to rapid advancements in new quantum-based technology April 12th, 2019

2D gold quantum dots are atomically tunable with nanotubes April 11th, 2019

'Nanobodies' from alpacas could help bring CAR T-cell therapy to solid tumors: Unusually small antibodies, targeted to the tumor micro-environment, curb melanoma and colon cancer in mouse models April 11th, 2019

Discoveries

A light-activated remote control for cells April 17th, 2019

Arrowhead Pharmaceuticals Receives FDA Clearance to Begin Phase 2/3 Study of ARO-AAT for Treatment of Alpha-1 Liver Disease April 15th, 2019

New microscopy method provides more details about nanocomposites April 12th, 2019

Oregon scientists drill into white graphene to create artificial atoms: Patterned on a microchip and working in ambient conditions, the atoms could lead to rapid advancements in new quantum-based technology April 12th, 2019

Announcements

A light-activated remote control for cells April 17th, 2019

NEXUS 2019: Global Summit on Energy Materials and Green Nanotechnology April 16th, 2019

Arrowhead Pharmaceuticals Receives FDA Clearance to Begin Phase 2/3 Study of ARO-AAT for Treatment of Alpha-1 Liver Disease April 15th, 2019

New microscopy method provides more details about nanocomposites April 12th, 2019

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

A light-activated remote control for cells April 17th, 2019

Oregon scientists drill into white graphene to create artificial atoms: Patterned on a microchip and working in ambient conditions, the atoms could lead to rapid advancements in new quantum-based technology April 12th, 2019

2D gold quantum dots are atomically tunable with nanotubes April 11th, 2019

'Nanobodies' from alpacas could help bring CAR T-cell therapy to solid tumors: Unusually small antibodies, targeted to the tumor micro-environment, curb melanoma and colon cancer in mouse models April 11th, 2019

Military

2D borophene gets a closer look: Rice, Northwestern find new ways to image, characterize unique material April 11th, 2019

Odd reaction creates a stir in the lab: Rice University researchers find using certain stir bars can create laboratory errors March 29th, 2019

Chemicals induce dipoles to damp plasmons: Rice University-led study finds molecules alter gold nanoparticles' electronic properties March 22nd, 2019

Fish-Inspired Material Changes Color Using Nanocolumns March 18th, 2019

Environment

NEXUS 2019: Global Summit on Energy Materials and Green Nanotechnology April 16th, 2019

Defects help nanomaterial soak up more pollutant in less time: Rice U. researchers find new way to remove PFOS from industrial wastewater March 13th, 2019

Oxford Instruments and partners launch EU Horizon 2020 project ULISSES: Air sensors for everyone, everywhere March 7th, 2019

Platinum forms nano-bubbles: Technologically important noble metal oxidises more readily than expected January 28th, 2019

Industrial

Nanoscribe is Technology Partner of the Research Project MiLiQuant: 3D microfabrication meets quantum technology - Miniaturized light sources for industrial use in the fields of quantum sensor technology and quantum imaging April 1st, 2019

Organic semiconductors: One transistor for all purposes March 22nd, 2019

Defects help nanomaterial soak up more pollutant in less time: Rice U. researchers find new way to remove PFOS from industrial wastewater March 13th, 2019

Zips on the nanoscale: New method of synthesising nanographene on metal oxide surfaces March 5th, 2019

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project