The energy density and environmental benefits of hydrogen have been coveted by many industries for a long time. The biggest problem, however, is that the cost of hydrogen fuel is too high. The good news is that a team of researchers at the Australian National University has increased the efficiency of solar hydrogen production to 17.6%. The also silicon-based photoelectric cathode design, which makes materials much more affordable than other high-performance competitors, represents an important step towards affordable clean hydrogen production.
(Photo: Australian National University)
As a lightweight, portable, easier-to-store clean energy, researchers in the fields of electric aviation, vertical take-off and landing aircraft, and renewable energy have a variety of good ideas about hydrogen.
But before the world can aggressively promote clean green hydrogen energy, there is still a need to improve the efficiency of hydrogen production. The good news is that scientists at the Australian National University (ANU) have come up with a new package.
It envisions a photochemical (PEC) solar hydrogen (STH) battery that could theoretically absorb both solar and water and then deliver hydrogen directly to the outside, rather than switching to an external electrolysis system.
By connecting cutting-edge calcium-titanium photovoltaic cells to electrodes, they are more efficient than any other device made with inexpensive semiconductors.
Lead researcher Dr Siva Karuturi, of the university’s School of Engineering and Computer Science, said: “The energy absorbed by photovoltaic panels is proportional to the semiconductor band gap, and silicon is the most popular photovoltaic material on the market, unfortunately producing only one-third of the energy needed to hydrolysis hydrogen.”
They were able to solve the problem by using semiconductors with a band gap that is twice as large as silicon. However, the trade-off is that the higher the band gap, the lower the efficiency of photovoltaic solar conversion.
Silicon-calcium titanium double absorption series photochemical cell can be directly hydrogen-producing
With this in mind, the research team used a smaller band gap of twice the semiconductor. In this way, it not only effectively converts solar energy, but also produces the necessary spontaneous hydrogen energy.
A key indicator of this system is the total efficiency from solar to hydrogen. The U.S. Department of Energy’s ultimate goal of nearly a decade is 25 percent, but reaching nearly 20 percent by 2020 will not be easy.
Previous designs have reached 19% of the time, but expensive semiconductor materials have been used. It is difficult to have a study that can reach a 10% level if you look only at parity-based solutions.
Fortunately, under relatively acceptable conditions, the efficiency of the silicon/titanium/platinum light electrode simply simulated in the lab has reached 17.6%.
Subsequent lysiers can further reduce manufacturing costs by fine-tuning the design of individual components to make hydrogen production more efficient and to replace valuable catalytic metals with abundant materials.
Details of the study have been published in the recently published journal Advanced Energy Materials.
Originally titled “Over 17% Efficiency Stand-Alone Solar Water Splitting Enabled by Perovskite-Silicon Tandem Absorbers.”