Texas Scientists Solve First Part of Scaled Hydrogen Energy Production
With the dire need to reduce global CO2 emissions, two decarbonization approaches — carbon capture and hydrogen — are receiving a lot of attention. Working together and separately, these technologies combined with efficiencies and greater use of renewable and nuclear power may hold the solution to a livable planet Earth in the future.
While carbon capture projects are scaling up, hydrogen energy has remained largely elusive due to the costs associated with its production. Recently, however, researchers at the University of Texas at Austin have made significant headway in this area. What do their findings mean for large-scale hydrogen production? And what does that, in turn, mean for energy transition?
Hydrogen as an Energy Source
Hydrogen is the most abundant element in the universe, and its potential for producing energy has been known since the late 18th century, when British scientist Henry Cavendish sparked hydrogen gas and produced water, thus demonstrating that water is composed of hydrogen and oxygen.
The biggest obstacle to using hydrogen energy is that hydrogen is usually found in combination with other elements. It generally takes a lot of energy (usually obtained from fossil fuels) to separate hydrogen gas, making it a complex and expensive fuel. However, it is an otherwise nonpolluting and zero-emission energy resource as it doesn’t produce carbon dioxide when combusted — only heat and water.
Despite its expense, hydrogen is already being used to produce pure water that powers cars, rockets, and electric systems. It is highly combustible and extremely powerful, yet it is non-toxic, transportable, and capable of being stored in fuel cells. Plus, it mixes well with other existing fuels. Hydrogen fuel is used in chemical manufacture, food processing, metal refining, and electronics manufacture. Also, it plays a vital role in the oil and petroleum industry, where it is used to produce refined fuels from crude oil and eliminate contaminants such as sulfur.
Current Ways of Producing Hydrogen Energy
Hydrogen is currently produced in two main ways:
· Steam reforming
Ninety percent of all hydrogen produced today is via steam reforming. The process involves a device called a reformer, which reacts with steam from hydrocarbon fuels at extreme temperatures to produce hydrogen. Commonly used hydrocarbon fuels include renewable liquid fuels, natural gas, diesel, gasified biomass, and gasified coal.
· Electrolysis (water splitting)
In electrolysis, direct current is used to prompt a chemical reaction that splits water into hydrogen and oxygen.
The electricity used in electrolysis is usually derived from fossil fuels, which emit greenhouse gases on combustion. Since the 1970s, scientists have experimented with solar power to generate this hydrogen-releasing reaction. But until now, all efforts have either proved too costly or resulted in a less-than-satisfactory performance. It was seemingly impossible to find materials both good at absorbing sunlight and robust enough not to degrade during water-splitting reactions.
The University of Texas at Austin Research
In July 2021, researchers from The University of Texas at Austin shared their discovery of a low-cost way to split off oxygen from water. Of course, it’s only one-half of the equation, but it’s a good start.
In a paper published in Nature Communications, Edward Yu of the Cockrell School’s Department of Electrical and Computer Engineering explains that materials that excel at absorbing sunlight are usually unstable under water-splitting conditions. However, the issue can be resolved by combining an absorbent material like silicon with a stabilizer like silicon dioxide. The challenge has then been making the silicon dioxide layer thin enough to allow the electrons and holes created in the silicon to pass through while maintaining stability.
The research team has solved this problem using a technique to make semiconductor electronic chips, making it easy to scale for mass production. They created electrically conductive paths through the silicon dioxide layer by coating it with aluminum. It’s then heated, creating “spikes” of aluminum that bridge the silicon dioxide layer. When exposed to sunlight, the device efficiently forms oxygen molecules by oxidizing water. At the same time, it generates hydrogen at a separate electrode and does not experience any degradation even over extended periods.
Dr. Yu and his team must still find a solution to the other part of the equation: releasing the hydrogen. They believe that can still improve the oxygen release, but in the meantime, they’ve started the process of patenting their technology.
Many experts regard hydrogen as the cornerstone of the new energy economy. The opportunity for an inconsistent renewable like the Sun to produce cheap, storable hydrogen allows it to be maximized. With the large-scale deployment of hydrogen production hopefully only just around the corner, it could soon be on a par with electricity as an energy carrier. From there, we can look forward to it playing a pivotal role in our transition to clean, renewable energy.