Photophysical Operando & Waste Energy Research (POWER) Laboratory
HSU Research Group
Group news
Our Solar-to-Fuel Tech Project Awarded HK Tech 300 Seed Fund
09th April 2026
We are pleased to share that our research team, led by Prof. Sam Hsien-Yi HSU at the School of Energy and Environment, has been approved for the HK Tech 300 Seed Fund (19th Cohort) with a total funding up to HKD 100,000. This support marks an important step in advancing our perovskite-based integrated photovoltaic–photoelectrochemical (PV–PEC) technology toward real-world applications.
Our awarded project, titled “Perovskite-Based Integrated Photovoltaic-Photoelectrochemical Systems for Sustainable Net-Zero Carbon Emissions and Value-Added Chemicals Conversion,” focuses on developing a self-powered photoelectrochemical system that directly converts atmospheric CO₂ into valuable chemical fuels using only sunlight. By integrating high-efficiency perovskite photovoltaics with catalytic conversion, the system simultaneously addresses climate change and energy storage challenges, offering a promising route for scalable artificial photosynthesis.
A key strength of our PePV–PEC platform lies in its ability to combine high-efficiency light absorption with selective CO₂ conversion, producing clean fuels and value-added chemicals without external power input. The technology is well-suited for applications in renewable energy storage, industrial carbon utilization, and sustainable chemical manufacturing. This solar-driven “Sun-to-Chemicals” approach contributes to a circular carbon economy and supports long-term net-zero emissions goals.
The HK Tech 300 Seed Fund provides crucial early-stage support for technology commercialization. Our team attended the Orientation Day on 9 April 2026 at Admiralty, Hong Kong, as required by the fund. We are grateful for the recognition from the selection panel and look forward to further improving system stability, catalytic efficiency, and scalability. Moving forward, we will continue advancing this PV–PEC technology toward practical deployment, contributing to a sustainable, low-carbon future powered entirely by solar energy.
Prof. Sam Hsien-Yi HSU (Principal Investigator); doctoral candidates Mr. Haihang Tong and Mr. Cong Jiang from the School of Energy and Environment, City University of Hong Kong.
Our Perovskite PV–PEC CO₂ Conversion Technology Wins Bronze Award at 51st International Exhibition of Inventions Geneva 🏅
14th March 2026
We are pleased to share that our research team, led by Prof. Sam Hsien-Yi HSU at the School of Energy and Environment, has been awarded the Bronze Award at the 51st International Exhibition of Inventions Geneva (IEIG 2026) for our work on a Perovskite Photovoltaic–Photoelectrochemical Tandem Platform for CO₂ Conversion.
Our award-winning project, “Perovskite Photovoltaic–Photoelectrochemical Tandem Platform for Carbon Neutrality and Green Synthesis,” presents a new generation of solar-driven “Sun-to-Chemicals” technology. By integrating a high-efficiency perovskite photovoltaic module with a dual-function photoelectrochemical reactor, the system directly converts sunlight into chemical energy—enabling CO₂ reduction at the photocathode while simultaneously performing value-added organic oxidation at the photoanode.
Prof. Sam Hsien-Yi HSU (left) and Mr. TONG Haihang (right) receiving the Bronze Award at the 51st International Exhibition of Inventions Geneva
A key strength of our PePV–PEC platform lies in its modular and scalable design. The system is well-suited for applications in distributed energy systems, industrial decarbonization, biogas and fermentation facilities, and sustainable chemical manufacturing. Coupling carbon utilization with chemical co-production enhances overall energy efficiency, improves economic viability, and reduces reliance on external power inputs.
During IEIG, the project attracted strong interest from international experts and industry representatives, who recognized its scientific novelty, engineering feasibility, and potential for real-world deployment. This award represents an important milestone for our team and further motivates us to continue improving system stability, catalytic performance, and scalability. Looking ahead, we will continue advancing this PV–PEC technology toward practical solar-driven carbon utilization solutions, contributing to net-zero carbon emissions and sustainable chemical manufacturing.
Professor Sam Hsien-Yi HSU Leads Breakthrough Study in Advanced Materials on Self-Repairing Single-Atom Catalysts
09th March 2026
The School of Energy and Environment (SEE) at City University of Hong Kong (CityUHK) is pleased to announce that Professor Sam Hsien-Yi HSU has led a significant research paper published in Advanced Materials, titled “Photoresponsive Adaptive Reconfiguration of Single-Atom Interface With Intermittent Light and Soft Ionic Lattices.”
This impactful study introduces a new paradigm for stabilizing single-atom catalysts (SACs), which are prized for their atom efficiency but prone to deactivation through aggregation or dissolution. The research team leveraged the soft ionic lattice and reversible dissolution–precipitation chemistry of halide perovskites to develop a bandgap-funnel architecture in mixed-halide MAPb(BrxI1-x)3. This design directs photogenerated carriers to atomically dispersed platinum (Pt) sites, while a programmable intermittent illumination strategy enables continuous regeneration of the catalytic interface. Under light, Pt single atoms are stably anchored for efficient hydrogen halide splitting; during dark periods, loosely bound species dissolve, preventing cluster formation and refreshing the surface.These findings represent an important advancement in catalysis science, demonstrating that ion mobility in perovskites—traditionally regarded as a stability limitation—can be harnessed as a functional mechanism for smart, self-repairing catalyst design. The adaptive reconfiguration mechanism enabled sustained hydrogen evolution at an average rate of 851 µmol h⁻¹ under visible light, with an apparent quantum yield of 15.5% at 450 nm, and maintained consistent activity over 72 hours of programmed light-dark cycling. Advanced characterization, including synchrotron X-ray absorption spectroscopy and aberration-corrected STEM, confirmed the atomic-level coordination of Pt and elucidated the light-regulated dissolution–redeposition dynamics.
These findings represent an important advancement in catalysis science, demonstrating that ion mobility in perovskites—traditionally regarded as a stability limitation—can be harnessed as a functional mechanism for smart, self-repairing catalyst design. The adaptive reconfiguration mechanism enabled sustained hydrogen evolution at an average rate of 851 µmol h⁻¹ under visible light, with an apparent quantum yield of 15.5% at 450 nm, and maintained consistent activity over 72 hours of programmed light-dark cycling. Advanced characterization, including synchrotron X-ray absorption spectroscopy and aberration-corrected STEM, confirmed the atomic-level coordination of Pt and elucidated the light-regulated dissolution–redeposition dynamics.
Professor HSU's contribution reflects SEE's strong commitment to advancing operando characterization, ultrafast photophysical spectroscopy, clean energy technologies and sustainable catalysis, reinforcing CityUHK's position as a leader in environmental and energy research.
The full article is available in Advanced Materials: https://advanced.onlinelibrary.wiley.com/doi/full/10.1002/adma.202518557
Our Perovskite PV–PEC CO₂ Conversion Technology Wins Silver Award at AEII
4-5th Dec 2025
We are excited to share that our research team, led by Prof. Sam Hsien-Yi HSU at the School of Energy and Environment, has received the Silver Award at the 5th Asia Exhibition of Innovations and Inventions (AEII) for our work on photovoltaic-powered perovskite-based photoelectrochemical (PV–PEC) devices for CO₂ conversion. Our “Photovoltaic-Powered Perovskite-Based Photoelectrochemical Device” wins silver medal at the 5th Asia Exhibition of Innovations and Inventions (AEII)
Our award-winning project, “Photovoltaic-Powered Perovskite-Based Photoelectrochemical Devices for the Co-Production of Renewable Fuels and High-Value Chemicals from CO₂,” showcases a new generation of solar-driven Sun-to-Chemicals technology. By integrating a high-efficiency perovskite photovoltaic module with a dual-function photoelectrochemical reactor, we directly convert sunlight into chemical energy, enabling CO₂ reduction at the photocathode while simultaneously carrying out value-added organic oxidation at the photoanode.
Team Members Receiving the Silver Award at the 5th Asia Exhibition of Innovations and Inventions (AEII) (from left to right: Mr. FENG Jianpei, Miss Wang Shuang, Prof. Sam Hsien-Yi HSU, Mr. TONG Haihang, Mr. Wang Zhe)
BPTR Innovation Wins Thailand Award for The Best International Invention & Innovation and Silver Medal at AEII 2025 🏅
4-5th Dec 2025
We are thrilled to announce that our invention, the Bio-Photoelectrochemical Tandem Reactor (BPTR), has been awarded The Best International Invention & Innovation Award from the National Research Council of Thailand (NRCT) and Silver Medal at the 2025 Asia Exhibition of Innovations and Inventions (AEII) Hong Kong, held on December 4-5, 2025.
These awards are recognized to acknowledge the breakthroughs with exceptional scientific novelty, inventive design, and strong commercialization potential. Receiving the NRCT’s Award is particularly meaningful, as it honors foreign inventions that demonstrate outstanding originality and global relevance. The BPTR system—capable of simultaneously treating wastewater and generating hydrogen using only sunlight and naturally occurring microorganisms—represents a new class of sustainable water-energy technologies, arising from the interdisciplinary collaboration, and technical innovation from our team. This achievement marks a significant milestone for our lab and reinforces our commitment to advancing sustainable clean energy and water-treatment technologies.
CityU Meeting
17th Nov 2025
Left to right: Prof XU Chenjie at CityUHK, Prof. Dirk M. Guldi at at Friedrich-Alexander-University Erlangen-Nuremberg, Andrey L. Rogach at CityUHK, Prof. Nguyễn T. K. Thanh at University College London, Dr. Jeremy Allen at Royal Society of Chem, Prof. Sam H.-Y. HSU at CityUHK, Prof. ZENG Xiaocheng at CityUHK
Prof. Dirk M. Guldi
17th Nov 2025
Prof. Sam H.-Y. HSU at CityUHK with Prof. Dirk M. Guldi at at Friedrich-Alexander-University Erlangen-Nuremberg at Chinese restaurant at CityUHK.
Highlighted by Energy & Environmental Science
Low-temperature highly selective Kolbe electrolysis of acetic acid in bio-oil on a stable in situ grown RuO2/TiO2 at industrial-level current
04th Jun 2025
This paper reports the development of a robust in situ grown RuO₂/TiO₂ electrode for low‑temperature Kolbe electrolysis of acetic acid (AA) in bio‑oil, achieving highly selective conversion of AA into energy‑rich ethane (C₂H₆) at industrial‑level current densities. The catalyst demonstrates excellent stability over 150 hours, sustaining high faradaic efficiency (~74%) and selectivity (~88%) even in complex bio‑oil matrices, while outperforming conventional binder‑based RuO₂ systems and offering a cost‑effective alternative to Pt electrodes. Mechanistic studies using in situ Raman and ATR‑FTIR spectroscopy reveal the unique selectivity toward AA and the competitive adsorption effects of other oxygenated organics, providing valuable insights into reaction pathways. Overall, this work establishes a scalable strategy for upgrading problematic AA in bio‑oil, enabling pH‑neutralization and valorization into clean hydrocarbon fuels.
Dr. Sam Hsu’s team unravels the interfacial dynamics of lead-free bismuth-based halide perovskites
7th Feb 2023
Dr. Sam Hsu (front row, left), Dr. Yunqi Tang (front row, right), and Mr. Mr. Stanley Chun Hong Mak (back row, right). For more details, please refer to CityU News (https://www.cityu.edu.hk/research/stories/2023/01/13/cityu-unravels-interfacial-interactions-lead-free-perovskite-efficient-hydrogen-production ).
