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Hydrogen is often described as a clean fuel because it produces only water when used. However, most hydrogen is currently produced from fossil fuels such as coal and natural gas, which limits its environmental benefits. Many scientists are working to create a ‘green cycle’, powered entirely by clean solar energy, which solves two problems at once: to obtain hydrogen not from agriculture waste or bio-methanol rather than fossil fuels, and to use that green hydrogen to consume carbon dioxide (CO₂) from the air and turn it into useful chemicals.

The team – a collaboration between Dalian Institute of Chemical Physics, Chinese Academy of Sciences, University of Trieste, and Fudan University – developed a method to produce ‘solar’ hydrogen and formaldehyde from bio-methanol using a photocatalyst synthesised by loading palladium single atoms and clusters onto a CdS photocatalyst. Palladium moieties with size-dependent defect states enable hole and electron trapping, respectively. This synergy led to the promoted breaking C–H and O–H bonds in bio-methanol to harvest hydrogen gas efficiently, whilst also producing formaldehyde. The quantum efficiency of the system reached 87% using a light wavelength of 455 nm. 

Another line of work focuses on storing hydrogen in liquid forms rather than as a gas. For example, compounds such as formic acid or formaldehyde can act as hydrogen carriers. These can be produced from biomass-derived feedstocks, including agricultural waste such as wheat straw, using light-driven processes and later converted back to release hydrogen when needed. This approach offers advantages for storage, transport and handling.

Hydrogen produced in these ways can also be used to reduce carbon dioxide. With suitable catalysts, COâ‚‚ can be converted into chemicals such as ethylene, which is widely used in the production of plastics. While efficiencies and stability depend on the specific system, advances in photocatalysis have significantly improved performance compared with earlier work.

Taken together, these developments point towards a more integrated system in which solar energy, biomass and carbon dioxide are linked. In such a system, renewable feedstocks provide the starting materials, sunlight supplies the energy, and carbon emissions are recycled into useful products.

This work contributes to the development of a circular carbon economy, where waste streams can be used as feedstocks, supported by renewable energy sources.

Feng Wang

Q&A

What are your feelings on receiving a Horizon Prize? 

Feng Wang: This prize is a pioneering award in the field. This recognition is a testament to the incredible dedication of my team and collaborators. Together, we are driven by a shared vision: to harness the power of sunlight and transform biomass and COâ‚‚ into clean energy and chemicals. By closing the carbon cycle, we strive to turn the dual challenges of waste and emissions into a sustainable future for all.

Paolo Fornasiero: Receiving this prize is a great honour and a strong encouragement. For me, environmental protection and sustainability have always been guiding principles of my research. At the same time, I am convinced that challenges of this complexity can only be addressed effectively through strong team collaboration, where complementary expertise makes it possible to achieve meaningful and impactful results.

Tiziano Montini: I feel proud to receive this prize. It is a sign that our efforts to build a more sustainable society have been recognised by an important institution such as the RSC.

Zhuyan Gao: As someone who has just recently graduated with a PhD, this prize will give me the courage to carry out more groundbreaking work in the future.

Junju Mu: I am deeply honoured and grateful to receive this recognition from the Royal Society of ÉîÒ¹¸£Àû¹ú²ú¾«Æ· alongside such an outstanding team. I started my academic journey in the UK and completed my PhD at the University of Manchester before returning to China to join Professor Feng Wang’s group at DICP. It feels especially meaningful to have our decade-long collaborative efforts acknowledged by the RSC. This prize belongs to every team member who contributed their unique expertise across disciplines and borders. It is a tremendous encouragement for us to continue pushing the boundaries of solar-driven hydrogen chemistry, and I feel privileged to be part of a community that values both scientific excellence and collaborative spirit.

Puning Ren: Very excited and satisfied; it is gratifying that our research is being recognised.

Ruotian Chen: I feel very honoured and proud to receive this prize as a member of the team.

Jianping Xiao: I was very surprised when I learned that I had received the award as a member of the team, followed by excitement and pride.

What was your role within the team? 

Paolo Fornasiero: My role within the team was twofold. I contributed to the project design and was continuously involved in the discussion and interpretation of the results, helping to guide the scientific direction of the work. In parallel, I was directly involved in the structural characterisation of the materials, working in close synergy with Prof. Montini from the University of Trieste, who provided key expertise, in particular through the use of synchrotron EXAFS techniques to understand the structure of the developed materials.

Ping Jin: My main contribution was the discovery and utilisation of a photoinduced heterolytic hydrogen dissociation mechanism, in which hydrogen was used to reduce carbon dioxide to ethylene with a yield close to 100%. This photocatalyst operated for over 1500 hours with an apparent quantum efficiency of 59%, approximately six times the best result for photocatalytic carbon dioxide reduction.

Junju Mu: My primary role focused on understanding the fundamental mechanisms of C–H and O–H bond activation in photocatalytic biomass conversion, particularly how hydrogen-bonding networks can be harnessed to promote selective alcohol C–C coupling and dehydrogenation. As a co-author on the hydrogen bonding study and the methanol C–H bond scission work, I was responsible for mechanistic investigations using in situ spectroscopy and kinetic analyses. I also contributed to the design of Pd-based photocatalysts with synergistic single-atom and cluster sites. Beyond the bench, my training in the UK helped facilitate communication between the DICP and University of Trieste teams, and my parallel research on CO₂ capture materials and AI-assisted catalysis brought complementary perspectives to the project’s broader vision of a circular carbon economy.

Rengui Li: My primary role within the team was to investigate and discuss the mechanistic pathways by which photogenerated charges on the photocatalyst participate in the reaction. In particular, I focused on photogenerated charge separation, transfer and utilisation processes, which represent central scientific questions and longstanding challenges in the field of photocatalysis. This topic has also been a long-term research focus of our team.

Fuxiang Zhang: I participated in data discussions and contributed suggestions for experimental design.

Zhuyan Gao: I participated in the design of experiments in the research on methanol dehydrogenation, led the collection and analysis of experimental data, and carried out the design of continuous flow reactors.

Wei Liu: As a team member participating in this work, I provided electron microscopy analysis of the gold–titanium dioxide catalyst. The TEM evidence, together with spectroscopy results, supports that an irradiation-induced TiOₓ layer in an H₂ atmosphere forms on the surface of gold nanoparticles on TiO₂. This encapsulating structure plays an important role in enabling heterolytic H₂ dissociation during the reaction.

Jianping Xiao: I analysed the reaction pathway and intermediates of CO₂ hydrogenation to ethane from the perspective of computational chemistry, and provided support for the view that illumination favours the coupling of the key intermediate CH₃* (Science, 2025, 389, 1037).

Ruotian Chen: My primary role was to demonstrate the existence of interfacial electric dipoles through mapping of the surface photovoltage.

What were the biggest challenges in this project, and how did you overcome them? 

Paolo Fornasiero: The biggest challenges were mainly related to timing and external constraints. The project reached its peak activity thanks to joint Italy–China funding from MAECI–MOST, which unfortunately coincided with the COVID-19 period. As a result, many planned collaborative activities such as researcher exchanges, visits, and experimental work at synchrotron facilities were interrupted and had to be replaced by remote interactions. In particular, it was very challenging to implement additional operando measurements at synchrotrons during such a complex period, especially to address reviewers’ requests under constrained access conditions. Nevertheless, these difficulties were progressively overcome through flexibility, remote coordination, and adaptation of the experimental strategy, and we are now close to celebrating the successful completion of the joint work.

Nengchao Luo: The biggest challenges of this project include two aspects. The first is associated with the efficiency of solar energy input for H₂ generation and utilisation. Breaking biomass C–H bonds with weak polarity is a challenge in the field of photocatalysis, especially using solar energy in the visible light region. Here, we devised a photocatalyst with supported oxidation and reduction co-catalysts that improved the light conversion efficiency to 87% using blue light. The combination of photocatalysis with thermal energy input enabled the conversion of saccharides to liquid hydrogen carriers powered solely by solar energy. The second aspect is overcoming the limitations of photocatalysis for CO₂ reduction, which is considered a promising method to decrease carbon emissions. We propose CO₂ reduction by negatively charged hydrogen species, which has been proven to be efficient for CO₂ reduction. We established hole and electron pairs at the interface, allowing heterolytic hydrogen dissociation. This light-induced H₂ dissociation enabled full CO₂ hydrogenation, producing ethylene with near-unity yield.

Tiziano Montini: One of the biggest challenges in the study of heterogeneous catalysts is the characterisation of the materials under real catalytic conditions. XAFS is one of the few techniques able to combine analysis of the elements involved in the active sites of the catalyst with the possibility of observing the materials in situ or under operando conditions.

Junju Mu: One of the greatest challenges was disentangling the trade-off between high conversion and product selectivity. This is a problem that has persisted in catalysis for over a century. In photocatalytic biomass conversion, the competing pathways of C–H versus O–H bond breaking make it particularly difficult to steer reactions towards a single desired product. We addressed this by systematically studying hydrogen-bonding effects. For example, we found that intermolecular hydrogen bonds between alcohol molecules and the photocatalyst surface could stabilise specific transition states, thereby tipping the selectivity.

Wei Liu: Catalysts operate through atomically defined active sites, which are crucial for elucidating activity mechanisms but are extremely difficult to verify experimentally. Using state-of-the-art, high-resolution analytical transmission electron microscopy, we directly visualised sub-nanometre-thick titanium oxide coatings on the exterior of the gold particles. These observations provide strong evidence supporting photo-induced catalyst activation via heterolytic Hâ‚‚ dissociation.

What different strengths did different people bring to the team? 

Paolo Fornasiero: The team brought complementary strengths that were essential for the success of the project. The DICP provided outstanding research infrastructure and capabilities, particularly in the field of photocatalysis, where its impressive array of parallel photoreactors enabled high-throughput experimentation. The scientific expertise within the institute is also excellent, ensuring strong experimental productivity and depth. At the same time, when researchers work very closely with their own data, there is always a risk of developing an overly positive interpretation or losing a broader perspective. For this reason, the international collaboration with an equally highly qualified team was crucial, as it allowed independent validation, cross-checking of results, and a more balanced and focused interpretation of the research outcomes.

Rengui Li: Our team brought together complementary expertise from multiple disciplines. Some members specialised in the controlled synthesis of catalytic materials, while others focused on the microscopic mechanisms of photogenerated charge behaviour. We also benefited from the contributions of theoretical scientists and experts in catalytic reactions. This interdisciplinary integration, combined with extensive discussion and close collaboration, was essential to advancing the project and achieving the final results.

Guoxiong Wang: The idea we proposed, that interfacial electric dipoles promote heterolytic Hâ‚‚ dissociation, is significantly different from general photocatalytic processes. It is precisely the continuous discussions among team members with different professional backgrounds that allowed us to break free from fixed thinking and to propose and refine this idea.

Ruotian Chen: Catalysis research covers many fields, such as materials and reactions, characterisation and analysis, and theory and experiment. Although a study may focus on breakthroughs in a particular field, it also requires support from other areas. The presence of different people in a team ensures the self-consistency of innovative ideas.

Why is this work so important and exciting? 

Nengchao Luo: Harnessing solar energy to produce hydrogen from biomass and utilise it for COâ‚‚ hydrogenation represents a critical step towards a sustainable energy future. This dual approach elegantly addresses two major challenges: securing clean energy and mitigating climate change. Using sunlight to convert abundant, renewable biomass (such as agricultural waste) into hydrogen offers a truly green alternative to fossil fuel-based production. It taps into the stored solar energy within plants, creating a carbon-neutral cycle. Simultaneously, employing the produced green hydrogen to convert waste COâ‚‚ into valuable fuels or chemicals (such as ethylene) through photocatalysis closes the carbon loop. This process not only captures COâ‚‚, it also upcycles it, transforming a greenhouse gas into a useful resource. By utilising sunlight as the sole energy input, this integrated system moves beyond simply reducing emissions.

Ping Jin: The conversion and utilisation of green and renewable solar energy, coupled with greenhouse gas conversion, are of great significance for environmental transformation and carbon resource utilisation.

Tiziano Montini: The work our group did in recent years is very important, in my opinion, as it is always devoted to improving the valorisation of waste to produce chemicals with a central impact on our future society, such as hydrogen. The process is based on the use of solar light as an energy source, which is free, abundant, equally distributed across our planet and not dependent on geopolitical issues.

Where do you see the biggest impact of this technology/research being? 

Feng Wang: This work contributes to the development of a circular carbon economy, where waste streams can be used as feedstocks, supported by renewable energy sources. It outlines a possible approach to an energy system that is clean, sustainable and integrated.

Junju Mu: I see the biggest impact in decentralised, off-grid chemical manufacturing, particularly in regions with abundant solar irradiation and agricultural biomass waste. Instead of relying on centralised fossil fuel-based hydrogen production and long-distance transportation, communities could use locally available biomass residues, such as wheat straw, as demonstrated in our pilot-scale apparatus, to generate hydrogen and organic hydrogen carriers on-site using only sunlight. Furthermore, the ability to directly convert biomass into C1 organic hydrogen carriers, effectively storing solar energy in liquid chemical bonds, circumvents the energy-intensive step of COâ‚‚ capture that is required in conventional hydrogen storage routes. In the longer term, the light-induced heterolytic hydrogen dissociation mechanism could influence industrial hydrogenation catalysis across multiple sectors, from COâ‚‚-to-olefins to green ammonia production.

Wei Liu: TiOâ‚‚-based catalytic systems have been widely studied over the past decades, serving as both practical and model catalysts. Extensive efforts, yielding a substantial body of knowledge, have been devoted to fabrication, microstructure tuning and dynamic reconstruction. However, photon-induced restructuring has been less well explored. In this work, we report that this benchmark catalyst exhibits significant activity for Hâ‚‚ dissociation during COâ‚‚ hydrogenation to ethylene.

How will this work be used in real life applications? 

Tiziano Montini: The work we have been carrying out in recent years within our collaboration could have important implications for real-life applications. I hope that our research will contribute to the large-scale production and use of fuels derived from biomass or from the reuse of atmospheric COâ‚‚, helping to reduce dependence on fossil fuels and environmental pollution.

How do you see this work developing over the next few years, and what is next for this technology/research?

Feng Wang: Following the discovery in this work, the next stage of research lies in using upstream biomass, such as wheat straw and corncob, to produce Hâ‚‚ directly with an appreciable yield. Considering the abundant sources of biogas, another line of research lies in converting gaseous mixtures from biomass gasification and fermentation into multi-carbon products without separation. This relies on new chemistry and breakthroughs in photocatalysis.

Guoxiong Wang: On the premise that the efficiency of photocatalysis reaches the level of thermal catalysis, scaling it up and pursuing large-scale applications is an important future direction.

How important would you say collaboration is for producing high-quality science? How has collaboration influenced your work?

Paolo Fornasiero: A Persian proverb says: ‘If you want to go fast, go alone; if you want to go far, go together.’ This is something I have truly learned through experience. Collaboration is essential for producing high-quality science, especially in complex fields where no single group can master all aspects, from theory to advanced characterisation and reactor design. I have personally seen this in my long-standing collaboration of over twenty years with my friend Ray Gorte at the University of Pennsylvania, which has been both scientifically and intellectually enriching. The same principle has guided my fruitful collaboration with the group of Feng Wang at DICP, where complementary expertise and shared critical discussion have significantly strengthened the quality and impact of the research.

Puning Ren: Almost no one can achieve breakthroughs in several cutting-edge areas of scientific research at the same time, but innovative work often requires the joint efforts of multiple fields, and I believe this is the value of collaboration. To date, all the research I have participated in has involved collaborators with different research backgrounds, which shows the importance of collaboration.

Rengui Li: I believe that deep and effective collaboration is essential for producing high-quality scientific research. Meaningful collaboration not only enables complementary expertise to be combined, but also helps researchers broaden their perspectives and address complex problems more efficiently. In my own work, collaboration has been valuable in refining scientific questions, strengthening mechanistic understanding and accelerating progress. I believe that the future of scientific research will increasingly depend on close and interdisciplinary collaboration.

In what ways does creativity influence how you think about or carry out your work? 

Paolo Fornasiero: Science advances through both small and large steps. Often, incremental progress follows the mainstream and leads to modest but important improvements in research. Larger breakthroughs, however, tend to emerge when one dares to think differently, to question established paths, and to explore directions that are not yet fully mapped. This is where creativity, curiosity and intuition play a crucial role. It is not always easy to ‘switch on’ creative thinking; it requires the right context, a certain level of calm, and often the right people around you. Sometimes, surprisingly, new ideas emerge outside the lab, after a good dinner with friends, a glass of prosecco, or simply a good coffee, when the mind is relaxed enough to connect ideas in new ways.

Junju Mu: Creativity in catalysis, for me, often means borrowing concepts from one field and applying them in another. My background is somewhat non-traditional, since I started in environmental science before moving into chemical engineering and eventually catalysis, and this interdisciplinary path has shaped how I approach problems. For instance, our idea of using hydrogen-bonding networks as a ‘molecular handle’ to control selectivity in photocatalytic alcohol coupling was inspired by supramolecular chemistry principles that are rarely applied in heterogeneous photocatalysis. Sometimes the most creative act in science is simply asking: ‘What if we tried this completely different approach?’

What do you wish more people understood about your field or the chemical sciences in general? 

Tiziano Montini: I wish more people understood how much effort chemists are investing in developing processes and technologies to sustainably produce chemicals and fuels, paying close attention to controlling, preventing and reducing environmental pollution.

Rengui Li: I hope more people will recognise the transformative potential of chemical sciences, particularly in the area of solar-driven photocatalysis. This field holds significant promise for the sustainable conversion of solar energy into chemical fuels and value-added products, and it may become an important direction in the future development of new energy technologies. More broadly, chemical science plays a foundational role in addressing global challenges related to energy, the environment and sustainability.

Thinking back to earlier in your career, are there any words of wisdom that you wish someone had told you? 

Paolo Fornasiero: Looking back, I wish someone had emphasised earlier how central collaboration is in tackling complex challenges in environment, energy and sustainability. Individual expertise is important, but real progress only emerges when different perspectives are genuinely integrated and critically discussed. I also learned that keeping a clear focus on realistic, testable steps is essential, even when working on highly visionary ideas. I came to understand this progressively through my experience and by meeting collaborators who have since become friends, which made this journey not only scientifically enriching but also personally meaningful.