Skip to main content
Intellect

Chemists turn gold to purple – on purpose

Color change confirms a new way to harvest energy from sunlight

  • BYU chemists develop an artificial system of photosynthesis using a common protein
  • The proof that it worked involved turning gold to the color purple
  • Next they will attempt to add an electrode so the energy can be harvested and stored

Professor Richard Watt and his chemistry students suspected that a common protein could potentially react with sunlight and harvest its energy – similar to what chlorophyll does during photosynthesis.

The story of how they proved it sounds as colorful as the legend of the leprechaun who hid his pot of gold at the end of the rainbow.

They started with citric acid from oranges and mixed it with the protein. Next they dissolved gold powder into the solution. Then they put vials of the yellow-colored mixture in direct sunlight and crossed their fingers in the hope that it would turn purple.

Here’s the reason why: If it turned purple, that would signal that the gold atoms had received electrons and used the donated energy to bunch together as small, purple-colored nanoparticles. And that would mean that the protein used the sunlight to excite the citric acid and trigger a transfer of energy.

While direct sunlight did the trick in about 20 minutes, a high-powered tungsten mercury lamp worked much faster.

“We set the system up, turned on the light, and the solution turned purple,” Watt said. “We knew that we’d proved the concept.”

The beauty of this experiment lies not in its colors – unless, of course, you’re thinking of it as a potential “green” energy source that keeps the environment clean.

The BYU researchers published their experiments in the Journal of Nanoparticle Research. The final step of this project will involve connecting the protein to an electrode to channel the energy into a battery or fuel cell. The BYU chemists will partner with Jae-Woo Kim of the National Institute of Aerospace for this next stage of the work.

Professor Watt’s pedigree includes a post-doc at Princeton, a father who developed a fuel cell that runs on sugar and weed-killer and a more distant ancestor credited with inventing the first practical steam engine. That ancestor is also the Scottish engineer for whom the unit of power “watt” is named.

Co-authors on the new study include BYU graduate Jeremiah Keyes, grad student Robert Hilton and Jeff Farrer, who runs an electron microscope lab at BYU.

Follow BYU news on Twitter: @BYU

Read More From

Related Articles

data-content-type="article"

Beyond diet: New BYU study links diesel exhaust to obesity and diabetes

October 09, 2024
A study co-authored by eight BYU students and three BYU faculty finds that exposure to the exhaust gas produced by diesel engines is tied to increased fat mass, enlarged fat cells, insulin resistance and inflammation. These changes can cause metabolic conditions such as obesity, diabetes, and heart disease.
overrideBackgroundColorOrImage= overrideTextColor= overrideTextAlignment= overrideCardHideSection=false overrideCardHideByline=false overrideCardHideDescription=false overridebuttonBgColor= overrideButtonText= overrideTextAlignment=
data-content-type="article"

Forum: “Why America went crazy and how you can stay sane”

September 24, 2024
David French, columnist for The New York Times and bestselling author, spoke to BYU students and employees in this week’s forum address at the BYU Marriott Center. He invited the audience to build unity with people they disagree with through friendship, connection and love.
overrideBackgroundColorOrImage= overrideTextColor= overrideTextAlignment= overrideCardHideSection=false overrideCardHideByline=false overrideCardHideDescription=false overridebuttonBgColor= overrideButtonText= overrideTextAlignment=
data-content-type="article"

BYU completes first-ever campus-wide sustainability assessment, earns distinction

September 24, 2024
BYU has been recognized as a STARS Gold Institution by the Association for the Advancement of Sustainability in Higher Education (AASHE). The sustainability report from AASHE considers BYU’s commitment to sustainability in academics, student and public engagement, operations, planning and administration, as well as its unique approach to earthly stewardship. BYU is one of only 140 institutions in the country to have been awarded a gold rating by AASHE.
overrideBackgroundColorOrImage= overrideTextColor= overrideTextAlignment= overrideCardHideSection=false overrideCardHideByline=false overrideCardHideDescription=false overridebuttonBgColor= overrideButtonText= overrideTextAlignment=
overrideBackgroundColorOrImage= overrideTextColor= overrideTextAlignment= overrideCardHideSection=false overrideCardHideByline=false overrideCardHideDescription=false overridebuttonBgColor= overrideButtonText=