Researchers at Rice University, Texas, US, have developed a catalytic reactor capable of re-purposing common greenhouse gas to produce pure liquid fuels. The renewable energy powered electrolyser uses carbon dioxide as its source of fuel as the reactor can then produce a high-concentration of purified formic acid.
Typically, this purification process to produce formic acid using carbon dioxide devices required massive amounts of energy at a high cost. Yet, the latest method, devised by Haotian Wang of Rice University’s lab of chemical and bio-molecular engineering, aims to clear the previous hurdles.
Formic acid is an energy carrier…It’s a fuel-cell fuel that can generate electricity and emit carbon dioxide…It’s also fundamental in the chemical engineering industry as a feed-stock for other chemicals, and a storage material for hydrogen that can hold nearly 1,000 times the energy of the same volume of hydrogen gas, which is difficult to compress.
Haotian Wang of Rice University’s lab of chemical and bio-molecular engineering
Wang continued, “That’s currently a big challenge for hydrogen fuel-cell cars.”
The latest developments, which led to the formation of the new device were realized due to “two advances” Chuan Xia, a post-doctoral researcher from Rice University, explained. The initial progression being the invention of a two-dimensional bismuth catalyst with the subsequent development being, eliminating the necessitation for salt as part of the reaction by generating a solid-state electrolyte. Furthermore, by moving forward in their methods of production the team manufacture the nanomaterials in large quantities.
“Bismuth is a very heavy atom, compared to transition metals like copper, iron or cobalt,” Wang said. “Its mobility is much lower, particularly under reaction conditions. So that stabilises the catalyst.” Wang underlined the fact that the reactor is constructed to prevent water from coming into contact with the catalyst, which also assists the preservation of it.
Currently, people produce catalysts on the milligram or gram scales…We developed a way to produce them at the kilogram scale. That will make our process easier to scale up for industry.
Chuan Xia, a post-doctoral researcher from Rice University
Usually processes aim to reduce carbon dioxide in a traditional liquid electrolyte like salty water. This is due to the necessity for the electricity to be conducted, but often pure water electrolyte is resistant. Thus, adding salts like sodium chloride or potassium bicarbonate allows the ions to move freely in water.
When you generate formic acid that way, it mixes with the salts…For a majority of applications, you have to remove the salts from the end product, which takes a lot of energy and cost. So, we employed solid electrolytes that conduct protons and can be made of insoluble polymers or inorganic compounds, eliminating the need for salts.
The ability to scale technology such as this up to industry standards is a stimulating prospect as many global studies and initiatives are pushing forward with developing new technologies and techniques that reduce global emissions and greenhouse gasses and commit to taking measures against the climate crisis.
Advances such as this are not necessarily a gateway to the panacea for all energy solutions or a silver bullet for solving the climate crisis, they could become a key factor when considering new approaches in slowing global warming - along with the continual development and research into other technologies such as solar, wind, and other renewables.
So, while the world is far from achieving the goals of the 2016 Paris climate accords, which seeks to prevent global temperatures from rising more than 2 degrees Celsius by 2100, the progress being made by scientists and researchers alike does offer a glimmer of hope.