Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Silver ions hurry up, then wait as they disperse: Rice chemists show ions’ staged release from gold-silver nanoparticles could be useful property

Chemists at Rice University and the University of Duisburg-Essen, Germany quantified the release of silver ions from gold-silver nanoparticle alloys. At top, transmission electron microscope images show the change in color as silver (in blue) leaches out of a nanoparticle over several hours, leaving gold atoms behind. The bottom hyperspectral images show how much a nanoparticle of silver and gold shrank over four hours as the silver leached away. (Credit: Rice University)
Chemists at Rice University and the University of Duisburg-Essen, Germany quantified the release of silver ions from gold-silver nanoparticle alloys. At top, transmission electron microscope images show the change in color as silver (in blue) leaches out of a nanoparticle over several hours, leaving gold atoms behind. The bottom hyperspectral images show how much a nanoparticle of silver and gold shrank over four hours as the silver leached away. (Credit: Rice University)

Abstract:
There’s gold in them thar nanoparticles, and there used to be a lot of silver, too. But much of the silver has leached away, and researchers want to know how.

Silver ions hurry up, then wait as they disperse: Rice chemists show ions’ staged release from gold-silver nanoparticles could be useful property

Houston, TX | Posted on April 23rd, 2021

Gold-silver alloys are useful catalysts that degrade environmental pollutants, facilitate the production of plastics and chemicals and kill bacteria on surfaces, among other applications. In nanoparticle form, these alloys could be useful as optical sensors or to catalyze hydrogen evolution reactions.

But there’s an issue: Silver doesn’t always stay put.

A new study by scientists at Rice University and the University of Duisburg-Essen, Germany, reveals a two-step mechanism behind silver’s dissipation, a discovery that could help industry fine-tune nanoparticle alloys for specific uses.

The team led by Rice chemists Christy Landes and Stephan Link and graduate student Alexander Al-Zubeidi and Duisburg-Essen chemist Stephan Barcikowski employed sophisticated microscopy to show how gold might retain enough silver to stabilize the nanoparticle.

Their study appears in the American Chemical Society journal ACS Nano.

The researchers used a hyperspectral dark-field imaging microscope to study gold-silver alloy nanoparticles containing an excess of silver in an acidic solution. The technique allowed them to trigger plasmons, ripples of energy that flow across the surface of particles when lit. These plasmons scatter light that changes with the alloy’s composition.

“The dependence of the plasmon on alloy composition allowed us to record silver ion leaching kinetics in real time,” said Al-Zubeidi, lead author of the study.

Al-Zubeidi noted films of gold and silver alloy have been in use for decades, often as antibacterial coatings, because silver ions are toxic to bacteria. “I think the silver release mechanism has been implied from studies of alloy films, but it’s never been proven in a quantitative way,” he said.

Initially, silver ions leach quickly from nanoparticles, which literally shrink as a result. As the process continues, the gold lattice in most instances releases all the silver over time, but about 25% of particles behave differently and silver leaching is incomplete.

Al-Zubeidi said what they observed suggests gold could be manipulated to stabilize the alloy nanoparticles.

“Usually silver leaching would last about two hours under our conditions,” he said. “Then in the second stage, the reaction no longer happens on the surface. Instead, as the gold lattice rearranges, the silver ions have to diffuse through this gold-rich lattice to reach the surface, where they can be oxidized. That slows the reaction rate a lot.

“At some point, the particles passivate and no more leaching can happen,” Al-Zubeidi said. “The particles become stable. So far, we’ve only looked at particles with a silver content of 80%-90%, and we found that a lot of the particles stop leaching silver when they reach a silver content of about 50%.

“That could be an interesting composition for applications like catalysis and electrocatalysis,” he said. “We’d like to find a sweet spot around 50%, where the particles are stable but still have a lot of their silver-like properties.”

Understanding such reactions could help researchers build a library of gold-silver catalysts and electrocatalysts for various applications.

Link said the Rice team welcomed the opportunity to work with Barcikowski, a leader in the field of nanoparticle synthesis via laser ablation. “This makes it possible to create alloy nanoparticles with various compositions and free of stabilizing ligands,” he said.

“From our end, we had the perfect technique to study the process of silver ion leaching from many single-alloy nanoparticles in parallel via hyperspectral imaging,” Landes added. “Only a single-particle approach was able to resolve the intra- and interparticle geometry.”

“This effort will enable a new approach to generate nanostructured catalysts and new materials with unique electrochemical, optical and electronic properties,” said Robert Mantz, program manager for electrochemistry at the Army Research Office, an element of the U.S. Army Combat Capabilities Command’s Army Research Laboratory. “The ability to tailor catalysts is important to achieve the goal of reducing soldier-borne weight associated with power storage and generation and enable novel material synthesis.”

Co-authors of the paper are Rice graduate students Charlotte Flatebo and Seyyed Ali Hosseini Jebeli and Duisburg-Essen graduate student Frederic Stein and researcher Christoph Rehbock. Link is a professor of chemistry and of electrical and computer engineering. Landes is a professor of chemistry and of electrical and computer engineering and chemical and biomolecular engineering. Barcikowski is a professor of chemistry at the Technical Chemistry Institute and the Center for Nanointegration at Duisburg-Essen.

The Army Research Office, a National Defense Science and Engineering Graduate Fellowship, the Robert A. Welch Foundation, the National Science Foundation and the German Research Foundation supported the study.

####

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 3,978 undergraduates and 3,192 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. 1 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger’s Personal Finance.

Follow Rice News and Media Relations via Twitter @RiceUNews.

For more information, please click here

Contacts:
Jeff Falk
713-348-6775


Mike Williams
713-348-6728

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

Read the abstract at:

Landes Research Group:

Link Research Group:

Stephan Barcikowski:

Department of Chemistry:

Wiess School of Natural Sciences:

Related News Press

News and information

Graphene key for novel hardware security May 10th, 2021

With a zap of light, system switches objects' colors and patterns: "Programmable matter" technique could enable product designers to churn out prototypes with ease May 6th, 2021

Polarization-sensitive photodetection using 2D/3D perovskite heterostructure crystal May 4th, 2021

Polarization-sensitive photodetection using 2D/3D perovskite heterostructure crystal May 4th, 2021

Chemistry

Researchers analyzed circulating currents inside gold nanoparticles: A new method facilitates accurate analysis of magnetic field effects inside complex nanostructures April 30th, 2021

Experiments cast doubts on the existence of quantum spin liquids April 21st, 2021

TPU scientists offer new plasmon energy-based method to remove CO2 from atmosphere March 19th, 2021

Teamwork makes light shine ever brighter: Combined energy sources return a burst of photons from plasmonic gold nanogaps March 18th, 2021

Govt.-Legislation/Regulation/Funding/Policy

Simple robots, smart algorithms April 30th, 2021

A silver lining for extreme electronics April 30th, 2021

Less innocent than it looks: Hydrogen in hybrid perovskites: Researchers identify the defect that limits solar-cell performance April 30th, 2021

New brain-like computing device simulates human learning: Researchers conditioned device to learn by association, like Pavlov's dog April 30th, 2021

Possible Futures

Graphene key for novel hardware security May 10th, 2021

With a zap of light, system switches objects' colors and patterns: "Programmable matter" technique could enable product designers to churn out prototypes with ease May 6th, 2021

Polarization-sensitive photodetection using 2D/3D perovskite heterostructure crystal May 4th, 2021

Polarization-sensitive photodetection using 2D/3D perovskite heterostructure crystal May 4th, 2021

Nanomedicine

World's first fiber-optic ultrasonic imaging probe for future nanoscale disease diagnostics April 30th, 2021

Arrowhead Announces Improvement in Fibrosis after ARO-AAT Treatment in Patients with Alpha-1 Liver Disease April 28th, 2021

Synthetic gelatin-like material mimics lobster underbelly’s stretch and strength: The membrane’s structure could provide a blueprint for robust artificial tissues April 23rd, 2021

CEA-Leti Announces EU Project to Mimic Multi-Timescale Processing of Biological Neural Systems: Targeted Applications Include High-Dimensional Distributed Environmental Monitoring, Implantable Medical-Diagnostic Microchips, Wearable Electronics & Human/Computer Interfaces April 23rd, 2021

Discoveries

Graphene key for novel hardware security May 10th, 2021

With a zap of light, system switches objects' colors and patterns: "Programmable matter" technique could enable product designers to churn out prototypes with ease May 6th, 2021

Polarization-sensitive photodetection using 2D/3D perovskite heterostructure crystal May 4th, 2021

Polarization-sensitive photodetection using 2D/3D perovskite heterostructure crystal May 4th, 2021

Materials/Metamaterials

Synthetic gelatin-like material mimics lobster underbelly’s stretch and strength: The membrane’s structure could provide a blueprint for robust artificial tissues April 23rd, 2021

Oregon scientists create mechanism to precisely control soundwaves in metamaterials: Theoretical modeling shows that designer materials incorporating drum-like membranes allow precise stoppage and reversal of sound pulses April 16th, 2021

FSU engineers improve performance of high-temperature superconductor wires April 16th, 2021

Better metric for thermoelectric materials means better design strategies: New quantity helps experimentally classify dimensionality of thermoelectric materials April 15th, 2021

Announcements

Graphene key for novel hardware security May 10th, 2021

With a zap of light, system switches objects' colors and patterns: "Programmable matter" technique could enable product designers to churn out prototypes with ease May 6th, 2021

Polarization-sensitive photodetection using 2D/3D perovskite heterostructure crystal May 4th, 2021

Polarization-sensitive photodetection using 2D/3D perovskite heterostructure crystal May 4th, 2021

Military

Simple robots, smart algorithms April 30th, 2021

With new optical device, engineers can fine tune the color of light April 23rd, 2021

Synthetic gelatin-like material mimics lobster underbelly’s stretch and strength: The membrane’s structure could provide a blueprint for robust artificial tissues April 23rd, 2021

Fast-acting, color-changing molecular probe senses when a material is about to fail March 25th, 2021

Grants/Sponsored Research/Awards/Scholarships/Gifts/Contests/Honors/Records

New brain-like computing device simulates human learning: Researchers conditioned device to learn by association, like Pavlov's dog April 30th, 2021

Controlling bubble formation on electrodes: Study finds the wettability of porous electrode surfaces is key to making efficient water-splitting or carbon-capturing systems March 26th, 2021

Building tough 3D nanomaterials with DNA: Columbia Engineers use DNA nanotechnology to create highly resilient synthetic nanoparticle-based materials that can be processed through conventional nanofabrication methods March 19th, 2021

Teamwork makes light shine ever brighter: Combined energy sources return a burst of photons from plasmonic gold nanogaps March 18th, 2021

Photonics/Optics/Lasers

With new optical device, engineers can fine tune the color of light April 23rd, 2021

New tech builds ultralow-loss integrated photonic circuits April 16th, 2021

Microscope that detects individual viruses could power rapid diagnostics March 19th, 2021

Teamwork makes light shine ever brighter: Combined energy sources return a burst of photons from plasmonic gold nanogaps March 18th, 2021

Research partnerships

Graphene key for novel hardware security May 10th, 2021

TPU scientists offer new plasmon energy-based method to remove CO2 from atmosphere March 19th, 2021

Quantum quirk yields giant magnetic effect, where none should exist: Study opens window into the landscape of extreme topological matter March 1st, 2021

Researchers improve efficiency of next-generation solar cell material: Reducing internal losses could pave the way to low-cost perovskite-based photovoltaics that match silicon cells’ output February 26th, 2021

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