A new publication from Opto-Electronic Advances discusses additional pathways to more sustainable electrocatalysts for efficient hydrogen technologies.
When fossil fuels are burned, large amounts of carbon dioxide, a greenhouse gas, are released into the atmosphere. Greenhouse gases that trap heat in Earth’s atmosphere are responsible for global warming. Rising sea levels, severe weather, loss of biodiversity, species extinction, food shortages, deteriorating health and increased poverty are all risks associated with a global average temperature increase of more than 1.5 degrees Celsius.
Slowing global warming before the planet changes beyond recognition is one of the most pressing challenges facing humanity today. A key part of tackling this type of climate change is reducing the use of fossil fuels and switching to zero- or negative-carbon renewable energy. The good news is that many countries are already grappling with this problem. For example, many countries have set challenging targets to reduce dependence on fossil fuels and switch to renewable energy sources. Solar power, geothermal, hydropower, wind power and biomass are all examples of renewable energy sources that can generate energy without accelerating global warming.
The whole world is searching for suitable alternatives to fossil fuels. At the same time, the discovery of hydrogen became a key turning point. Things began to change after the invention of hydrogen, as researchers learned that the element was an efficient energy carrier that could be a good replacement for fossil fuels. But there was a problem: finding free hydrogen was impossible. Since it is a highly reactive non-metal, it never occurs freely in nature and can only be produced from other energy sources.
Then, a green, environmentally friendly and sustainable method called electrochemical oxidation/reduction of free radicals became the savior for the production of hydrogen, ammonia, hydrocarbons and other fuels. Mostly, the electrochemical fuel generation of hydrogen and oxygen proceeds through the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively.
But this hydrogen technology requires highly active and stable HER catalysts, while the rare element platinum (Pt) is used in water-splitting devices. The catalyst, Pt, makes the technology more expensive, and the production of platinum involves toxic chemicals that affect our ecosystems.
Furthermore, the reaction rate appears to be very slow due to the non-local concentration of free radicals around the electrocatalyst (Pt). While this reaction can be accelerated by increasing the free radical concentration through a large electrode potential with the help of electricity, this solution is also costly.
The authors of this article developed a physical and multifunctional design approach to enhance the electrocatalytic fuel generation performance to a broad range through their high-performance electrode (LIPSS). They say, “Layered LIPSS on an electrode with periodic ridges and grooves with a width of 100-300 nm must be covered by spherical nanoparticles (NPs) with a diameter of 3-94 nm, and then the reagent concentration effect induced by the local electric field is enhanced At these periodic ridges and NPs can significantly enhance the performance of electrochemical fuel generation for HER and OER.”
In experiments testing the performance of this catalyst, the authors found that by using this optimized LIPSS pattern morphology, the current electrode achieves the highest hydrogen production rate of about 3×1016 Molecular cm-2Second-1 At a current density of 10 mA/cm2. Compared with the Ni foam electrode without any LIPSS pattern, the electrode potential of this value is about 45% lower. Precise and controllable fabrication of LIPSS on electrodes can significantly enhance its performance as a sustainable electrocatalyst for efficient hydrogen generation. On LIPSS-patterned nickel foam substrates, the HER model electrocatalyst exhibits a 10 overpotential of 130 mV (40%) or lower and high stability in HER.
Furthermore, the OER model electrocatalysts on LIPSS patterned NF substrates require a 10 overpotential of more than 100 mV (25%) in OER and exhibit higher stability.
Furthermore, a low potential of 330 mV is sufficient to drive a 10 mA/cm2 In the overall water splitting plot, compared to similar cells made from pristine nickel foam electrodes. The patterned LIPSS electrocatalysts operate at much lower potentials, suggesting that the femtosecond laser patterning method has great potential to generate green catalysts.
Based on the above process, it is believed that the new insights presented in this study will pave the way to demonstrate a single-step, fast and better physical method for patterning electrode surfaces that can be applied to any metal and semiconductor catalysts to reduce the amount of electrons required for various electrochemical reactions. electrical energy.
According to recent findings from the Chinese Academy of Sciences (CAS), Li and his research group are getting closer to achieving this goal. Their technique is still in the research stage, but appears to be a promising energy source.
The ultimate goal is to create a so-called hydrogen extraction catalyst that is reliable and sustainable for the planet.
The authors of this paper look forward to seeing their method hit the market in the next few years and to see its worldwide impact grow.