Solar Water Splitting to Fuels Conversion – Patent Landscape Study

Researchers have always realized hydrogen, one of the lightest elements, to be a promising green fuel and a potential energy store. Today, most hydrogen production plants require fossil fuels (natural gas, in most cases) to generate electricity, which is further utilized for electrolyzing water to produce hydrogen. These fossil fuels include, but are not limited to coal, petroleum, natural gas and even nuclear energy. Since the water splitting process is a highly endothermic process, therefore tremendous energy is used to dissociate H2O into H2 and O2.

We all know that one energy form, solar energy, is available to us in plethora. But the major challenge in utilizing solar energy to split water is low energy conversion efficiency and high cost involved, as well as reduction in the cost of the electrolyzer unit.

Patent landscape – an overview

Recent IP filings have shown that 43.65% of total patent literatures have been filed between the years 2012 and 2017, showing the interest of the scientific community in this technological field. The R&D in this technological field is expected to grow at CAGR of nearly 23% between 2017 and 2022. The Hydrogen production market in terms of value is estimated to be approximately USD 150 Billion by 2022. The majority of research has been carried out mainly in China, the United States, Japan and Germany, with China leading the way.

In China, researchers from academia are highly involved in this technology. 36.9% of total patents have been filed by universities & research institutes. Notable ones are:

  • Bohai University;
  • East China University of Science and Technology;
  • Xi’an University of Architecture and Technology;
  • Technical Institute of Physics and Chemistry;
  • Dalian Institute of Chemical Physics; and
  • University of Electronic Science and Technology of China.

Researchers from these universities also started to focus on materials like perovskite-structured transition metal oxynitrides (such as those based on gallium and tellurium) as a new type of photocatalyst with high visible light content. In 2015, researchers from Bohai University filed their patents focusing on photocatalytic materials that can be activated by visible light as well ultraviolet light such as CATON, CMTON and CSTON. These materials have shown high efficiency, stability and water splitting efficiency.

Also Read: Patent Landscape Study on Artificial Retina

Major industry players:

Overall, the patent filings in this domain suggest that the significant focus of all inventions lies in:

  • Improvement in reduction of greenhouse gas emission
  • Improvement in energy conversion efficiency
  • Production of hydrogen with inexpensive manufacturing cost
  • Improvement in the efficiency of a photosynthetic system        
  • Improvement in photoactive material

Recent advancements

Initially, the inventions were based on conducting catalytic reactions using different photocatalyst and then carrying the electrolysis of water, thereby, effectively converting the solar energy into hydrogen energy. Afterwards, patents were filed to overcome the problem of costly process involved in the direct conversion of solar energy into electricity, which on the other hand has lower efficiency. Such problems were overcome by using thermochemical water dissociation by solar energy to produce hydrogen.

Due to the dynamic nature of the technology, the focus of researchers shifted towards improvement in photoactive materials to improve higher energy conversion efficiency, improving the limited lifetime and efficiency of hydrogen production device and reduction in waste of resources.

The technology took a sharp turn when organizations like Hyper Solar introduced next generation semiconductor material such as titanium silicides, nickel silicide, iron silicides, thallium silicide, boron silicide, cobalt silicide etc. that absorbs solar or artificial radiation energy to split water and produce hydrogen and oxygen at a relatively low cost.

From thereon, the focus of the invention lies in improving the properties of photoactive materials and devices that can be used for improving the photocatalytic reaction rate leading to higher energy conversion efficiency.

Trending today

  • Govinder Singh Pawar, researcher  at  the University of Exeter, Britain, has pushed the world one step closer to being pollution-free by creating a photoelectrode that can store solar energy more efficiently than any other method we know today and also use it to generate enough voltage to extract hydrogen from water for fuelling the world.
  • Scientists from Kyushu University have synthesized a compound that absorbs near-infrared light to produce hydrogen from water. The compounds consist of three ruthenium atoms connected by an organic molecule. This is the first successful use of infrared light to produce hydrogen by water splitting.


Fulfilling the growing demand of energy while keeping in mind the idea of sustainable development is a major challenge in front of the scientific community. With the depletion of fossil fuels, it is evident that the world will rely on renewable energy sources like solar energy and fuels like hydrogen fuel. Till now, the use of hydrogen as a fuel is limited, but advances in chemistry and physics behind the technology like solar water splitting are at peak. In order to fully leverage the potential of this technology, researchers must work on improving the energy conversion efficiency by utilizing different combinations of photocatalytic materials and photoactive materials to improve the performance of reactions involved in the energy conversion process.

– Satyender Kumar, Parteek Saxena (Engineering Team) and The Editorial Team

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