Connect with us

Review published in Science shows Earth-abundant metals are poised for greater use

When it comes to industrial catalytic reactions, platinum-group metals rule.

A Shining Example of Nature Leading the Way

When it comes to industrial catalytic reactions, platinum-group metals like palladium rule. But there’s an alternative that holds promise called Earth-abundant metals.

From oil refining to automobile pollution-control devices to the bulk of pharmaceuticals, platinum-group metals (PGMs) are the go-to choice for facilitating chemical reactions. It’s been that way for decades. Platinum-group metals boast thermal stability, ease of use in catalysis, and tolerance to chemical poisons. Perhaps the most prominent case in point is the widespread use of the precious metal palladium in the manufacturing of pharmaceuticals and electronic materials. The 2010 Nobel Prize in Chemistry, in fact, was awarded to the researchers credited with developing palladium-catalyzed cross coupling.

But there’s an alternative. And for significant reasons, that alternative—Earth-abundant metals (EAMs)—holds the promise of offering a choice that rivals PGMs.

“That’s true,” said Morris Bullock, a Lab Fellow at Pacific Northwest National Laboratory where he is Director of the Center for Molecular Electrocatalysis, “but don’t expect Earth-abundant metals to be coming to your town any time soon as a ready alternative to all platinum-group metals.”

1597384281 579 A Shining Example of Nature Leading the Way

Earth-abundant metals, depicted above as their chemical symbol and atomic weight, are being explored as alternatives to precious metals currently used in industrial processes. Image: Nathan Johnson/PNNL

Industry leans heavily on platinum-group metals

Earth-abundant metals catalysts have been used more widely in recent years. But they’ve still lagged the platinum group, in part, because of a lack of fundamental scientific knowledge about their potential, argues a research review published Aug. 14 in the journal Science.

1597384281 426 A Shining Example of Nature Leading the Way

The precious metal palladium is used for manufacturing pharmaceuticals and electronic materials.

Bullock was lead author of the article, the result of an April 2019 U.S. Department of Energy meeting of experts to discuss EAMs.

“We critically examined the literature that’s been published about Earth-abundant metals in recent years and, essentially, issued a call to action for more research about the subject,” said Bullock.

More availability and lower cost

Earth-abundant metals have several desirable attributes. As the name suggests, there are a lot more EAMs readily available. There’s as much as 10,000 times more EAMs than PGMs, and that translates to lower extraction and production costs.

While palladium, with its Nobel Prize credentials, is a shining example of PGMs’ industrial production track record, it also has no peer in terms of cost. Commodity markets this year have priced palladium at more than $2,000 an ounce. On top of that, palladium is mined in an extremely limited number of locations globally, none of which are in the United States or its territories.

Not only are Earth-abundant metals cheaper, they’re cleaner, too

Earth-abundant metals, sometimes called base metals, are less toxic than their platinum-group cousins. Their relative abundance generally leads to a lower environmental footprint associated with their mining and purification compared to PGMs. For example, the Science review notes the production of a kilogram of the platinum group’s rhodium generates the equivalent of more than 35,000 kilograms of carbon dioxide. The CO2 production of a kilogram of nickel? About 6.5 kilograms. Also, rhodium costs almost as much per ounce as pricey palladium, while nickel costs less than $7 per pound.

Granted, a metal’s extraction cost is only part of the equation. Platinum-group metals continue to be the prevalent choice in many industrial catalytic processes because their inherent properties make them the best metal for the job, the review notes. It points to the appeal of corrosion-resistant PGMs in fuel cells as well as the ideal high-temperature suitability of platinum, rhodium, and palladium in automobiles’ catalytic converters.

Nature may provide the path to greater
EAM use

The review article, titled, “Using nature’s blueprint to expand catalysis with Earth-abundant metals,” suggests researchers look outside the laboratory for clues in designing new catalysts using EAMs for chemical reactions.

“We believe that nature provides invaluable guidance for frontier areas of exploration in EAM catalysis,” said Yogesh Surendranath of MIT, also a corresponding author of the paper. “We looked at how versatile the reactions are that happen in nature—all with Earth-abundant metals. Nature can catalyze many amazingly complicated reactions.”

In short, PGMs may rule in the factory, but nature is EAMs’ domain. Biological organisms must accumulate metals from their surroundings for their own catalysis, whereas there are no known native biological catalysts that use a PGM. Many of the transformations in nature carried out by enzymatic EAM catalysts, the article notes, are replicated in the chemical industry with platinum-group catalysts.

“Replicating how nature does it is the challenge,” said Bullock. “Part of the problem is that enzymes in nature’s catalysis are really complicated and not easily translated to a laboratory setting, let alone a factory.”

Earth-abundant metals are rooted on some factory floors

Meanwhile, EAM catalysts are used in several major industrial processes. Converting nitrogen to ammonia, for example, relies on an iron-based catalyst–even though ruthenium, a PGM alternative, is more efficient. Other examples: hydrogenation of carbon monoxide to methanol uses a copper- and zinc-based catalyst; nickel- and iron-based catalysts combine with water in commercial electrolyzers to produce hydrogen; and cobalt- and manganese-catalysts help make terephthalic acid—a key component of polyester fibers and plastic bottles.

1597384281 95 A Shining Example of Nature Leading the Way

Earth-abundant metals, like iron, are used as catalysts for several industrial processes.

“There’s still a long way to go,” predicted Jingguang Chen of Columbia University and Brookhaven National Lab, and a corresponding author, “before science replicates catalytic reactions with EAMs that can rival the reliability seen now with PGMs, which are firmly entrenched in industrial uses.”

“In the last few years, though, there’s been a better understanding of how to interrogate these base-metal molecules to understand how they are reacting—by building on the fundamental scientific understanding of this chemistry, using new techniques that reveal details of how the reactions occur. We’re getting closer.”

This research is based on work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences.

Review article co-authors include Jingguang G. Chen, Department of Chemical Engineering, Columbia University, New York, and Brookhaven National Laboratory; Laura Gagliardi, Department of Chemistry, Minnesota Supercomputing Institute, and Chemical Theory Center, University of Minnesota; Paul J. Chirik, Department of Chemistry, Princeton University; Omar K. Farha, Department of Chemistry and Chemical and Biological Engineering, Northwestern University; Christopher H. Hendon, Department of Chemistry and Biochemistry, University of Oregon; Christopher W. Jones, School of Chemical and Biomolecular Engineering, Georgia Institute of Technology; John A. Keith, Department of Chemical and Petroleum Engineering, University of Pittsburgh; Jerzy Klosin, Dow Chemical Co.; Shelley D. Minteer, Department of Chemistry, University of Utah; Robert H. Morris, Department of Chemistry, University of Toronto; Alexander T. Radosevich, Department of Chemistry, Massachusetts Institute of Technology; Thomas B. Rauchfuss, School of Chemical Sciences, University of Illinois; Neil A. Strotman, Merck & Co. Inc.; Aleksandra Vojvodic, Department of Chemical and Biomolecular Engineering, University of Pennsylvania; Thomas R. Ward, Department of Chemistry, University of Basel (Switzerland); Jenny Y. Yang, Department of Chemistry, University of California, Irvine; Yogesh Surendranath, Department of Chemistry, Massachusetts Institute of Technology.

Source: PNNL




Source link

0
Continue Reading

Technology

Opera for Android, Desktop Browsers Get Redesigned Sync Capabilities

Opera for android desktop 1600851955578

Opera has launched updated versions of its browsers for Android and desktop. Opera for Android version 60 and Opera for Desktop version 71 come with completely redesigned sync capabilities between them, the company says. The new feature uses a QR code scan to establish a connection between Opera on an Android device and the Opera desktop browser on Windows, macOS, or Linux. The Opera browser for Android also comes with the popular Flow feature as well as Suggested Sites feature on the homepage. In meanwhile, the Opera desktop browser now comes with the Easy Files feature.

Opera for Android 60

With Opera browser for Android, users can navigate to opera.com/connect on their PCs or tablets and scan the QR code displayed there with the QR code reader located in the search bar of the browser. As soon as this is done, the new Sync feature will start synchronising all their passwords, bookmarks, speed dials, typed browsing history and open tabs, as well as the newly-integrated Flow feature across devices.

The new Sync feature of Opera for Android does do not require any login credentials to sync data across devices.
Photo Credit: Opera

Stefan Stjernelund, Product Manager of Opera for Android, says that people don’t sync their phones with their PCs “because they hate the hassle of having to type in their logins and lengthy passwords.” He notes that the QR code scan feature can help users to quickly sync data across devices that do not require any login credentials. “Opera was the first browser to offer sync between mobile and desktop browsers 13 years ago. Today we’re taking a big step forward by making it easier than ever,” added Stjernelund.

Apart from the new syncing feature, Opera for Android 60 also gets the Flow feature from the Opera Touch browser. This feature allows users to share files, links, YouTube videos, photos, and personal notes with themselves, between their Opera mobile and desktop browsers. So, if you’re searching something on Opera on your Android smartphones, you can quickly share it on the desktop version. According to the brand, Flow is end-to-end encrypted so anything stored will only be known to the user. In Opera for Android, Flow can be accessed from the O-menu.

 

Opera for Android 60 now also comes with Suggested Sites feature that allows for “speed dials” in the browser. According to the brand, the speed dial section is now smarter and more dynamic as it identifies the user’s most frequently visited websites. It displays them just below the traditional speed dial section. “Suggested Sites gives us a quicker way to engage with relevant content without the need to manually add pages to the speed dial or bookmarks,” Stjernelund noted. Users have a choice to easily disable this feature.

Additionally, Opera for Android offers a built-in free unlimited browser VPN, a QR code scanner, a crypto wallet, and a cookie dialog blocker. You can download Opera for Android 60 via Google Play.

Opera for android desktop sync feature intext Opera for Android

Flow feature allows users to share files, links, videos and photos between their Opera mobile and desktop browsers
Photo Credit: Opera

Opera for Desktop 71

The Opera for Desktop version 71 browser comes with the Easy Files feature that offers most recently downloaded files that essentially makes attaching files in the Opera browser easy. It is also claimed to feature a high level of privacy and security. It features a built-in browser VPN, ad blocker, as well as built-in messengers, including WhatsApp, Telegram, Instagram and Facebook.


How are we staying sane during this Coronavirus lockdown? We discussed this on Orbital, our weekly technology podcast, which you can subscribe to via Apple Podcasts or RSS, download the episode, or just hit the play button below.

Source link

0
Continue Reading

Technology

The best hidden features in iOS 14

ios14 hidden features

Apple’s iOS 14 is full of new features, but some of the best gems are the ones in obscure places. Learn about the best hidden features in iOS 14 and how to use them on your iPhone and iPad.

Image: CNET

When Apple’s iOS 14 was released last week, many users and developers were surprised by the next-day availability. iOS 14 includes big changes that will forever change the way we use our iOS devices: From the widgets on the Home Screen, to the App Library, to the new automations in Shortcuts, iOS is clearly moving at a fast pace and bringing many new headlining features. Read about the best iOS 14 hidden features that many users skip over. 

SEE: Apple iPadOS: A cheat sheet (free PDF) (TechRepublic)

Listen for sounds

One accessibility feature that Apple added to iOS 14 was the ability for your iPhone to listen for particular sounds and then alert you whenever it encounters them. This feature is fantastic for hard of hearing or deaf users who need assistance in identifying when the door bell rings, an animal makes a noise, etc.

To enable this feature, perform the following steps: 

  1. Open the Settings app.
  2. Navigate to Accessibility | Sound Recognition.
  3. Select the toggle to ON.
  4. Select Sounds.
  5. Toggle on the sounds that you’d like your device to recognize and alert you to (Figure A).

Figure A

ios14-hidden-features-figure-a.jpg

Your iPhone can recognize multiple sounds on-device and alert you to them. This list of recognizable sounds will grow over time.

As of iOS 14, your phone can do on-device sound recognition of four different categories of sounds: Alarms, Animals, Household, and People. This set of sounds will grow over time based on advances in machine learning and device microphones. You can enable or disable the particular individual sounds you’re concerned with.

Apple notes that, with this feature enabled, your iPhone will continuously listen for sounds using on-device intelligence and notify you when the sounds are recognized. Because of this your battery life may take a slight hit, and this will also utilize on-device storage to process the sounds.

In addition, Apple notes that this shouldn’t be relied upon for emergency situations or navigation.

SEE: How to use widgets on the Home Screen in iOS 14 (TechRepublic)

New color picker

There’s a new color picker that you will encounter in both Apple and third-party apps that brings about a new way on iOS to select colors that we’re excited about. If you’ve spent any time in macOS, you’ve undoubtedly encounter the macOS Digital Color Meter that’s available systemwide. Apple now has a new color picker on iOS 14 that brings a few new ways of selecting colors, and saving them.

We’ll show how to do this in Notes, but the feature is also available in other apps. In Notes, select the drawing tool, then select the color picker icon. When you do this, the new color picker will appear (Figure B). 

Figure B

ios14-hidden-features-figure-b.jpg

The new iOS 14 color picker brings the same tools from macOS to iOS for picking colors.

The first section you’ll encounter is a standard color grid which shows a few hues to let you quickly pick a color. The next tab is the Spectrum, which lets you get more fine-grained control over every color available to pick on the device and it’s opacity. The last tab is Sliders, which we’re very excited about. This view lets you pick or enter RGB values, or a hex value to set the color—a feature that hasn’t been available on iOS except in speciality apps before.

SEE: iOS 14 App Library: How to use it on your iPhone (TechRepublic)

Lastly, you’ll notice the custom palette organizer at the bottom of the color picker. In this section, you can save your favorite colors by tapping the + button, or tap and hold on any of them to delete them. You can save up to 10 colors in this section for easily switching between apps, or projects.

Hide the Hidden Photos album

The Hidden photo album has been available in the Photos app for years, but it has been far from hidden on iOS devices. Rather, it was a folder called Hidden that just stored photos you didn’t want visible in your main Photo library. Now you can also hide this folder so that the hidden photos are truly hidden.

To do this, perform these steps:

  1. Open Settings.
  2. Navigate to Photos.
  3. Scroll near the bottom, and disable the toggle for Hidden Album.

With this option deselected, the Hidden album will no longer appear in the Albums tab of Photos. To show it again, re-enable the toggle. 

Dictation shortcut

On iPadOS 14, there’s a new way to assign a keyboard shortcut for text dictation. This lets you easily still use dictation even when an external keyboard is attached without the need to use the on-screen controls for dictation.

To enable this feature, perform these steps:

  1. Open Settings.
  2. Navigate to General | Keyboard | Dictation Shortcut.
  3. Select an available Shortcut (Figure C).

Figure C

ios14-hidden-features-figure-c.jpg

Selecting a dictation shortcut will let you easily double-tap the selected button on a hardware keyboard to start the dictation process without needing to use the on-screen controls.

The available shortcuts are either Control or Command. Select one or the other, then activate by quickly double-pressing the selected shortcut when your cursor is in a text field.

Hide Home Screens

Apple introduced the App Library for iPhone, and it allows a lot of customization and cleanup for iOS Home Screens for the first time in the history of the iPhone. You can still have multiple Home Screens in iOS 14, but sometimes you may want to disable messy Home Screens or Home Screens of apps that you don’t access frequently.

To disable a Home Screen on your iPhone:

  1. Tap and hold on the Home Screen to enter jiggle mode.
  2. Tap the dots denoting page numbers. 
  3. Tap the checkmark under the Home Screen to remove it, tap again to add it back (Figure D).

Figure D 

ios14-hidden-features-figure-d.jpg

Hiding Home Screens allows users to clean up their icons and hide pages of apps that aren’t always needed.

Select Done when finished and your changes will be saved. Any hidden pages will be skipped over when swiping left or right between Home Screens.

Back tap gesture

If you have an iPhone 8 or newer, then we saved the best feature for last in this tip lineup. That’s because the back tap feature is one of those hidden gems that will change your digital life once you’ve implemented it.

SEE: Apple releases iOS 14 without this privacy feature: What iPhone users and developers need to know (TechRepublic)

With this feature, you can assign a double- or triple-tap gesture to the back of your iPhone. When you tap the back of the device with your finger twice or three times, it can perform an action that you assign. Yes, you read that right, you can perform an action by just tapping the back of your iPhone with your finger, and it even works with a case.

To set up this feature:

  1. Open Settings.
  2. Navigate to Accessibility | Touch | Back Tap.
  3. Select Double Tap or Triple Tap to set up actions for one or both.
  4. Select an action (Figure E).

Figure E

ios14-hidden-features-figure-e.jpg

Myriad shortcuts are available to the back tap feature. You can even launch an app through a Shortcuts workflow.

There are many system, accessibility, scroll, and even app shortcuts available–you can even create your own Shortcut workflows and assign them to a double- or triple-tap gesture. The possibilities are limitless when it comes to assigning actions for this feature. 

Also see

Source link

0
Continue Reading

Technology

NIST Scientists Get Soft on 3D Printing

Gel Neuron R2 2 cropped 600x450 1

New method could jump-start creation of tiny medical devices for the body.

NIST Scientists Get Soft on 3D Printing

Illustration of a prospective biocompatible interface shows that hydrogels (green tubing), which can be generated by an electron or X-ray beam 3D printing process, act as artificial synapses or junctions, connecting neurons (brown) to electrodes (yellow). Image credit: A. Strelcov/NIST

Researchers at the National Institute of Standards and Technology (NIST) have developed a new method of 3D-printing gels and other soft materials. Published in a new paper, it has the potential to create complex structures with nanometer-scale precision. Because many gels are compatible with living cells, the new method could jump-start the production of soft tiny medical devices such as drug delivery systems or flexible electrodes that can be inserted into the human body.

A standard 3D printer makes solid structures by creating sheets of material — typically plastic or rubber — and building them up layer by layer, like a lasagna, until the entire object is created.

Using a 3D printer to fabricate an object made of gel is a “bit more of a delicate cooking process,” said NIST researcher Andrei Kolmakov. In the standard method, the 3D printer chamber is filled with a soup of long-chain polymers — long groups of molecules bonded together — dissolved in water. Then “spices” are added — special molecules that are sensitive to light. When light from the 3D printer activates those special molecules, they stitch together the chains of polymers so that they form a fluffy weblike structure. This scaffolding, still surrounded by liquid water, is the gel.

Typically, modern 3D gel printers have used ultraviolet or visible laser light to initiate formation of the gel scaffolding. However, Kolmakov and his colleagues have focused their attention on a different 3D-printing technique to fabricate gels, using beams of electrons or X-rays. Because these types of radiation have a higher energy, or shorter wavelength, than ultraviolet and visible light, these beams can be more tightly focused and therefore produce gels with finer structural detail. Such detail is exactly what is needed for tissue engineering and many other medical and biological applications. Electrons and X-rays offer a second advantage: They do not require a special set of molecules to initiate the formation of gels.

But at present, the sources of this tightly focused, short-wavelength radiation — scanning electron microscopes and X-ray microscopes — can only operate in a vacuum. That’s a problem because in a vacuum the liquid in each chamber evaporates instead of forming a gel.

Kolmakov and his colleagues at NIST and at the Elettra Sincrotrone Trieste in Italy, solved the issue and demonstrated 3D gel printing in liquids by placing an ultrathin barrier — a thin sheet of silicon nitride — between the vacuum and the liquid chamber. The thin sheet protects the liquid from evaporating (as it would ordinarily do in vacuum) but allows X-rays and electrons to penetrate into the liquid. The method enabled the team to use the 3D-printing approach to create gels with structures as small as 100 nanometers (nm) — about 1,000 times thinner than a human hair. By refining their method, the researchers expect to imprint structures on the gels as small as 50 nm, the size of a small virus.

Some future structures made with this approach could include flexible injectable electrodes to monitor brain activity, biosensors for virus detection, soft micro-robots, and structures that can emulate and interact with living cells and provide a medium for their growth.

“We’re bringing new tools — electron beams and X-rays operating in liquids — into 3D printing of soft materials,” said Kolmakov. He and his collaborators described their work in an article posted online Sept. 16 in ACS Nano.

Reference:

T. Gupta, et al. “Electron and X-ray Focus Beam Induced Crosslinking in Liquids: Toward Rapid Continuous 3D Nanoprinting of Soft Materials.“. ACS Nano (2020)

Source: NIST




Source link

0
Continue Reading

Trending