Hydrogen has emerged as the key piece for cleanse energy of our planet and leave behind our dependence on fossil fuels. Unlike gasoline or gas, when we use hydrogen as an energy source, we don't release a single speck of CO2 into the atmosphere. The problem is that, until now, most of the hydrogen we use is so-called "gray" hydrogen, obtained through methane reforming, a process that, ironically, emits enormous quantities of gases greenhouse effect.
To make the leap to green hydrogen, we need water electrolysis to be viable and, above all, cheap. This is where catalysts come into play—those components that accelerate the chemical reaction so that it isn't a slow and expensive process. The major headache has been that, for this to work well, especially in the PEM electrolyzer upgrade, have been needed extremely rare and expensive metals such as platinum or iridium, which makes scaling the technology to an industrial level a real headache.
The cobalt revolution and the magic of water
Recently, a group of scientists from ICFO in Barcelona, ​​along with other institutions such as ICIQ and ICN2, have hit the nail on the head with a brilliant solution. Instead of searching for a new metal, they changed their strategy: they created a catalyst based on cobalt, a very abundant material and economical, managing to survive in the most corrosive acidic environments where normally only iridium could withstand the strain.
The secret to this breakthrough lies in a process called delamination. Essentially, they've used cobalt-tungsten oxide and removed the tungsten so that water and hydroxyl groups fill those gaps. This structure not only protects the metal from dissolving in the acid, but also increases the number of active sites where the reaction occurs. Thanks to this, they have achieved extremely high current densities (1 A/cm2) with a stability exceeding 600 hours, marking a milestone for iridium-nondependent catalysts.
Nickel and Iron: the bet on scalability
On the other hand, the University of Valencia, through the ICMol, has developed another very promising route focused on layered double hydroxides of nickel and ironThese elements are not critical and are easy to find, making them perfect for mass production. Their manufacturing method is particularly sustainable as it is carried out room temperature and under mild conditions, using an epoxide-based reaction.
This material has proven to be particularly efficient when integrated into anion exchange membrane fuel cells (AEMWE). By reducing the energy required to split the water molecule, the process becomes much more competitive with fossil fuels. In fact, this technology has already been licensed to the Matteco company so that it can reach the factories and help meet the European Union's climate goals.
Hydrogen straight from the sea and the power of sound
One of the biggest challenges is that electrolysis consumes a lot of fresh water, a scarce resource in sunny or windy places like Australia. To solve this, researchers at RMIT have designed a catalyst that nitrogen-doped molybdenum nickel phosphide which allows the use of seawater. Most impressively, they have managed to block the chlorine and prevent the salt from corroding the system, aiming to produce green hydrogen at a price of $1,40 per kilo.
In addition, there is an innovative technique from the University of Melbourne that uses ultrasound waves During electrolysis, ultrasound prevents gas bubbles from adhering to the electrodes, increasing the amount of hydrogen produced fourteenfold. Furthermore, this method allows to do without acidic electrolytes, eliminating the need to use platinum or iridium to protect the materials, which drastically reduces the final production cost.
Self-repair and efficiency systems in Korea
From South Korea, Seoul National University is exploring "Electrochemical Activation" (EA). Instead of coating the electrodes with noble metals, they use commercial nickel electrodesBy applying a reducing voltage, an iron layer is created that acts as a catalyst. The most surprising thing is that the system is capable of self-repairWhen efficiency drops, a small electrical pulse reactivates the electrode surface.
This system has demonstrated stability for over 1.000 hours, suggesting it is fully scalable. For the transportation sector, this is music to their ears, as it would allow them to... fuel cell vehicles have a much cheaper and more sustainable fuel supply, making it easier for aviation and urban mobility to definitively abandon oil.
The transition to a decarbonized economy depends on our ability to produce green hydrogen without relying on scarce materials. Thanks to the combination of new structures based on cobalt, nickel, and iron, the ability to use seawater, and the application of self-repairing ultrasound or pulsed electrical energy, we are achieving the electrolysis is efficient, cheap and viable on a global scale, opening the door to a completely clean transport and industry.
