Abstract
A research team, affiliated with UNIST has announced the development of a stable and efficient chalcogenide-based photoelectrodes, addressing a longstanding challenge of corrosion. This advancement paves the way for the commercial viability of solar-driven water splitting technology-producing hydrogen directly from sunlight without electrical input.
Jointly led by Professors Ji-Wook Jang and Sung-Yeon Jang from the School of Energy and Chemical Engineering, the team reported a highly durable, corrosion-resistant metal-encapsulated PbS quantum dot (PbS-QD) solar cell-based photoelectrode that delivers both high photocurrent and long-term operational stability for photoelectrochemical (PEC) water splitting without the need for sacrificial agents.
PEC water splitting is a promising route for sustainable hydrogen production, where sunlight is used to drive the decomposition of water into hydrogen and oxygen within an electrolyte solution. The efficiency of this process depends heavily on the stability of the semiconductor material in the photoelectrode, which absorbs sunlight and facilitates the electrochemical reactions. Although chalcogenide-based sulfides, like PbS are highly valued for their excellent light absorption and charge transport properties, they are prone to oxidation and degradation when submerged in water, limiting their operational stability.
Traditionally, maintaining stability required the addition of expensive sacrificial agents, which hampers economic feasibility. (original version: which are neither economically sustainable nor environmentally friendly.)
Researchers at UNIST introduced a novel configuration that encapsulates PbS quantum dots with two types of metals-nickel (Ni) and Field's metal (FM)-to create a robust barrier against corrosion. The Ni foil acts as both a physical shield and an efficient catalyst for water splitting, while the FM layer forms a seamless seal around the QDs, effectively blocking moisture entry.
Furthermore, a key discovery was that UV light penetrates the PEC system, accelerating degradation of internal layers. To counter this, they engineered an inverted layered structure that absorbs UV light within the outer PbS layer, shielding the vulnerable internal electron transfer pathways from UV-induced damage.
The new photoelectrode achieved a record-high photocurrent density of 18.6 mA/cm² in a 1.0 M NaOH solution, maintaining approximately 90% of its initial performance after 24 hours of continuous operation. When further optimized with UV-blocking features, the electrodes demonstrated stable operation for over 100 hours without performance loss.
Professor Jang commented, "Despite their excellent photoelectrochemical properties, the instability of metal sulfides has limited their practical use. Our approach eliminates the need for expensive sacrificial agents, while achieving high efficiency and long-term durability, bringing us closer to commercial solar hydrogen production."
This research was participated by Hwa-Young Yang, Muhibullah Al Mubarok, Sarang Kim, and Su-Ho Lee, as first authors with support from the National Research Foundation of Korea (NRF) and the Ministry of Science and ICT (MSIT), and the InnoCORE program. The findings of this research have been published in Nature Communications on December 11, 2025.
Journal Reference
Hwa-Young Yang, Muhibullah Al Mubarok, Sarang Kim, et al., "Stable and efficient PbS quantum dot photoelectrodes enable photoelectrochemical hydrogen production without sacrificial agents," Nat., Commun., (2025).
