Professor Fatwa Firdaus Abdi Advances Pressurized Solar Hydrogen Research in Nature Communications
Prof. Fatwa Abdi, Associate Professor of the School of Energy and Environment (SEE), City University of Hong Kong (CityUHK), has achieved a pioneering advance in hydrogen technology. His latest publication, “Photoelectrochemical water splitting cells at elevated pressure using BiVO4 and platinized III‑V semiconductor photoelectrodes”, has been published in Nature Communications. The study demonstrates the successful operation of solar water‑splitting devices at pressures up to eight bar and reveals that the performance benefits of elevated‑pressure operation depend critically on the specific materials and device configuration.
Most hydrogen end‑use applications, ranging from fuel cells to industrial processes, require the gas to be delivered at elevated pressures. Conventional approaches rely on energy‑intensive mechanical compression after hydrogen generation, which adds complexity and cost to the system. This study addresses that longstanding challenge by demonstrating the direct photoelectrochemical (PEC) production of pressurized green hydrogen, thereby reducing or eliminating the need for downstream compression. To the best of current knowledge, this represents the first experimental realization of PEC water splitting at elevated pressures up to eight bar.
Using a custom‑designed high‑pressure PEC flow cell, his research examined two representative device configurations. In back‑illuminated metal oxide‑based PEC cells, elevated pressure alleviated photocurrent saturation under high solar concentrations by suppressing gas bubble formation. Operando imaging directly confirmed this pressure‑driven mitigation of bubble‑induced losses, resulting in a substantial increase in photocurrent—approximately 40 percent at five bar under ten‑fold simulated sunlight. In contrast, front‑illuminated platinized triple‑junction III‑V PEC cells exhibited photocurrent that remained largely unaffected by pressure. This outcome is attributed to long charge carrier diffusion lengths and a nanoparticulate catalyst morphology that minimizes the impact of gas bubbles, even at eight bar.
Taken together, these findings underscore the interplay between photoelectrode architecture, gas evolution behaviour, and charge transport properties in determining high‑pressure performance. Beyond being a technical demonstration, the study provides actionable insights into how PEC water splitting systems can be engineered for direct integration into pressurized hydrogen infrastructure.
This breakthrough strengthens SEE’s position at the forefront of sustainable hydrogen research and contributes meaningfully to global efforts to develop efficient, scalable, and cost‑effective clean energy solutions.
The full paper is available at: https://doi.org/10.1038/s41467-025-67294-3
