Jeonbuk National University (JBNU) Professor Hee‑dae Kim (Department of Semiconductor Science and Technology) and his research team have developed a multifunctional energy material capable of simultaneous hydrogen production and energy storage, and systematically analyzed synthesis techniques and application potentials for converting bio-waste into high-value quantum dots, publishing their results consecutively in international journals.

These research outcomes were published in the international journals Renewable and Sustainable Energy Reviews and Advanced Composites and Hybrid Materials. The former has an impact factor of 16.3 and ranks in the top 2.7% of SCI journals, while Advanced Composites and Hybrid Materials has an impact factor of 23.2 and ranks in the top 1.4% of SCI journals.

The research involved JBNU researcher Kirti Bhardwaj and researcher S. R. Shingte as first authors, respectively, and Professor Hee‑dae Kim served as the corresponding author on both papers. The work was carried out as an international collaborative study with research teams from Shivaji University and The New College in India, and the University of Mons in Belgium.

In the energy materials study, the team fabricated a heterostructured composite combining nickel–cobalt selenide and the highly electrically conductive two-dimensional material Ti3C2Tx MXene. They precisely controlled the nanostructure and pore characteristics formed during synthesis by using different solvents, including water–ethanol mixed solvent, ethylene glycol, and acetone.

As a result, the NCSM-WE composite produced in the water–ethanol mixed solvent formed a uniformly interconnected nanoflake structure and exhibited the best performance. The material’s specific surface area was 56.68 m²/g, larger than that of materials prepared using ethylene glycol and acetone. This large surface area and interconnected microporous structure facilitated electrolyte ion transport and increased the number of active sites for electrochemical reactions.

The NCSM-WE composite recorded low overpotentials of 258 mV and 146 mV for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), respectively, in water-splitting processes. Lower overpotentials mean the water-splitting reactions can be driven with less energy, improving the energy efficiency of hydrogen production. In addition, both reactions showed almost no performance degradation over 50 hours, confirming long-term operational stability.

Notably, the team drew attention by comprehensively presenting the potential and application areas of technologies that convert bio-waste into quantum dots. They analyzed various synthesis techniques, including hydrothermal synthesis, pyrolysis, microwave-assisted synthesis, and chemical oxidation, and showed that the photoluminescent properties of bio-waste-derived quantum dots are determined not only by particle size but also by a complex interplay of surface functional groups, structural defects, heteroatom doping, and molecular luminophores.

Based on this, they proposed that bio-waste-derived quantum dots can be applied in diverse fields such as biosensing and bioimaging, medical diagnostics, detection of environmental pollutants, photocatalysis, drug delivery, and optoelectronic devices. The finding that waste can be transformed from a disposable material into a feedstock for next-generation nanomaterials is considered a meaningful achievement for the circular economy and the development of environmentally friendly advanced materials.

Professor Hee‑dae Kim said, "This study is significant in that it demonstrates the possibility of precisely controlling the structure and interfacial properties of nanomaterials to enhance both energy production and storage performance, while converting discarded bio-waste into high-value nanomaterials. Going forward, based on eco-friendly material technologies, we will expand applications not only to hydrogen production and energy storage but also to the bio, environmental, and optoelectronic fields."