Supported by the Russian Science Foundation, researchers from the Federal Research Center "Boreskov Institute of Catalysis SB RAS" and the Competence Center of the National Technology Initiative "Hydrogen as the Basis of a Low-Carbon Economy" are developing photocatalytic and photoelectrochemical processes to produce pure hydrogen from ammonia at room temperature. This technology shows promise for treating large volumes of ammonia generated by wastewater treatment facilities and other sources.
Research on hydrogen production from ammonia began in the early 21st century and has gained increasing attention in recent years (e.g., France is building a pilot ammonia cracking plant). Traditional ammonia decomposition is a thermal catalytic process that requires temperatures above 600°C and uses catalysts containing 5–10wt% platinum. Scientists at the Boreskov Institute of Catalysis decided to explore room-temperature photocatalytic and photoelectrochemical methods that can be initiated with just 1% platinum.
The researchers employed semiconductors such as titanium dioxide, tungsten oxide, zinc oxide, and silver phosphate. Systems composed of metal-coated semiconductors enable a two-stage conversion process: ammonia reduction occurs on metal particles, while oxidation takes place on the semiconductor surface. Spatial charge separation makes the process significantly more energy-efficient.
In addition to improving energy efficiency, a major focus is reducing platinum loading. Previous studies have shown that platinum usage can be substantially decreased without loss of activity, and even cheaper alternatives may be found.
Dr. Dina Markovskaya, researcher in the Department of Heterogeneous Catalysis at the Boreskov Institute, emphasized that the main advantages of photocatalytic and photoelectrochemical ammonia decomposition are the ability to use renewable solar energy, operation at room temperature and atmospheric pressure, lower energy costs, and enormous environmental potential. The technology can be integrated into industrial wastewater treatment systems: solar photocatalytic reactors can simultaneously remove ammonia impurities from water and generate additional hydrogen, forming a closed loop. Given the scale of industrial wastewater, the practical potential of this approach is immense.
Currently, the scientists are conducting in-depth studies of the kinetics and mechanism of ammonia decomposition on the developed catalysts — crucial for evaluating the real-world viability of the technology. In the future, they plan to create composite photocatalysts with improved redox performance.
