Split water using photocatalytic hydrogen evolution


Split water

Researchers developed a novel molybdenum-coated catalyst that can efficiently split water with acidic electrolytes, and could help with efficient production of hydrogen.

When catalyst burns, hydrogen is converted into water and heat to make an entirely clean power source. Thus, in the quest for greener power, there is an urgent need for a sustainable and efficient means of producing it.

To split water using a process known as photocatalytic hydrogen evolution. Using sunlight, water molecules split into hydrogen and oxygen to provide the necessary energy.

By developing an optimal catalyst, scientists are searching for the ways of improving the water-splitting reaction.

Researchers from King Abdullah University of Science & Technology (KAUST) create a hydrogen-evolution reaction catalyst that is both acid-tolerant and selectively prevents the water-reforming reaction1.

acid-tolerant catalyst

Angel Garcia-Esparza former KAUST Ph.D. student, said, the development of acid-tolerant catalysts is an important challenge because most materials are not stable and quickly degrade in the acidic conditions that are favorable for hydrogen generation.

The team takes a time to establish the optimal pH level between 1.1 and 4.9, because the acidity of the solution was crucial for the stability of the material.

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They then electro-coated molybdenum onto a standard platinum electrode catalyst in a mildly acidic solution.

Comparing the performance of the photocatalyst, the team showed without molybdenum the rate of hydrogen production is eventually reached after 10 hours of operation under illumination by ultraviolet light.

However, researchers believe that the molybdenum acts as a gas membrane, preventing oxygen from reaching the platinum and disrupting its catalytic performance.

Researchers said, the main challenge for most catalysts is the long-term stability of the materials. So, acid-tolerant material capable of preventing the water-forming back reaction that slows down water splitting.

More information: [Angewandte Chemie]