With the expansion of solar power generation raising concerns about the disposal of end-of-life solar panels, domestic researchers have opened a new avenue for utilizing them as a resource. A research team led by Professor Jong-Beom Paik of the Department of Energy and Chemical Engineering at Ulsan National University of Science and Technology (UNIST) announced the development of a method to simultaneously produce high-purity hydrogen and industrial silica using silicon from discarded solar panels.

The research team published their findings in the online edition of the international academic journal Joule on March 27. Subsequently, on April 3, they were invited to the 'Future Energy' section of the same journal to introduce the potential for industrial application of the technology.

Silicon can react with water to produce hydrogen and silica, but the silica film that forms on the surface has blocked the reaction, severely limiting hydrogen production. The research team devised a mechanochemical process capable of removing this film without the use of strong chemicals. By rolling silicon and water together in a container filled with small beads to induce collisions, they repeatedly removed the protective silica film, thereby sustaining the reaction.

As a result of the experiment, approximately 1706 mL of hydrogen was produced per 1 g of commercial silicon. This corresponds to 99.6% of the theoretical maximum, significantly surpassing the efficiency of existing thermochemical methods, which remained at 18–28%. In experiments using silicon obtained directly from waste panels, performance reaching approximately 98% of the theoretical value was also recorded.

The potential of the co-produced silica as a catalyst support was confirmed. The research team explained that the nickel catalyst utilizing this material demonstrated higher conversion rates and selectivity than commercial silica in the reaction converting carbon dioxide into methane. This was analyzed to be due to the effect of hydroxyl groups (-OH) on the silica surface, which better disperse the catalyst particles.

It is also highly significant in terms of economic feasibility. Even excluding revenue from silica sales, the unit cost of hydrogen production was tens to thousands of times cheaper than conventional methods. It is assessed that if silica is taken into account, a structure where profits are actually generated during the production process is possible. The research team predicted that if the process is converted to a continuous system, it will be easy to apply even in large-scale industrial sites.

"Professor Baek Jong-beom said, 'This is highly significant in that it can convert waste solar panels into resources rather than simple waste,' adding that 'it will contribute to establishing a circular economy.' This research was conducted with support from the Ministry of Science and ICT and the National Research Foundation of Korea.