Among the many research directions in renewable energy, why did you and your team choose to focus on hydrogen?

Hydrogen (H₂) is currently regarded as one of the most promising energy carriers for the future, particularly due to its high energy density by weight, which is three-times greater than that of oil and over 100-times higher than that of lithium-ion batteries. However, hydrogen also faces a significant challenge: its energy density by volume is extremely low, at nearly zero. This means that storing and transporting hydrogen requires advanced liquefaction under extremely high pressure or innovative storage solutions using solid or liquid carriers, both of which pose considerable challenges in terms of cost and safety.

Today, hydrogen is categorized by “color”, based on the energy source used for its production. Green hydrogen is produced from renewable energy such as solar, wind, or nuclear power and emits no CO₂. Gray or black hydrogen is derived from natural gas (methane), and while its use only emits water, the production process releases CO₂. White hydrogen, meanwhile, is a naturally occurring form found in geological deposits, recently discovered in countries such as France, Albania, and the US. If successfully extracted, it could become an ideal replacement for fossil fuels. Notably, these white hydrogen deposits have been found at depths of around 1,000 meters in areas previously mined for metals like iron and chromium.

While Vietnam has yet to conduct dedicated research in this area, our geological conditions, rich in metal deposits such as iron and chromium, make this a promising possibility. This is a relatively new field globally, which gives us the chance to join early and potentially become a leader, provided there is a clear policy commitment and strategic investment.

What approaches have your team taken in researching and developing hydrogen technology in Vietnam?

The production of green hydrogen involves converting solar energy to split water into hydrogen and oxygen. There are two main technological approaches. The first is converting sunlight into electricity using photovoltaic (PV) panels, then using that electricity to electrolyze water. This is the most commonly used method today. The second is directly converting sunlight into hydrogen through photoelectrochemical catalysts, also known as “artificial leaves”. This is the direction our team is currently pursuing.

What are the key conditions for green hydrogen to become competitive in the market?

According to the US Department of Energy, in order for green hydrogen to compete with gray or black hydrogen without subsidies, the technology must meet two critical criteria.

First, the solar-to-hydrogen conversion efficiency must reach at least 10 per cent, with 25 per cent being the ideal target.

And second, the operating lifespan of the components must exceed 10,000 hours, which is roughly equivalent to three years of use, assuming an average of eight hours of sunlight per day.

Component durability is considered a major bottleneck in hydrogen technology. What are your thoughts on this?

That’s absolutely correct. Even when using materials considered highly durable, component degradation remains a significant challenge. For example, the most efficient system to date, developed by Professor Thomas Jaramillo’s research group at Stanford University in the US, achieves a conversion efficiency of around 30 per cent. However, it still experiences rapid performance loss. After just 48 hours of operation, the system loses nearly 4 per cent of its efficiency.

So, while the efficiency exceeds the minimum 10 per cent benchmark, it still falls short of the requirement for a continuous operating lifespan of 10,000 hours. Durability remains a major hurdle that limits the commercialization of green hydrogen technologies on a large scale; a challenge that the global scientific community is actively trying to overcome.

Given that Vietnam has issued its National Hydrogen Development Strategy, how do you assess its current capabilities and ecosystem?

Vietnam released its National Hydrogen Development Strategy in early 2024, setting the goal of producing and exporting green hydrogen by 2030. However, five years is not a long time, especially considering the current limitations in domestic research capacity and technological readiness.

At USTH, our team consists of only seven researchers, two postdoctoral fellows, and four PhD students, which is a modest number compared to what is needed. That said, we take pride in the fact that over the past decade we have supported more than 40 talented young Vietnamese in pursuing doctoral studies abroad, most of them in fields related to hydrogen energy and CO₂ reduction. This is a pool of experts we could mobilize for a national-level research and development initiative on hydrogen energy, if such a program was to be established.

Currently, our team is leading an international collaborative project on green hydrogen development, funded by the French National Center for Scientific Research (CNRS) for the 2025-2029 period. The project involves two research teams in Vietnam and two in France, including one led by Dr. Vincent Artero and a prominent group from the French Alternative Energies and Atomic Energy Commission (CEA) specializing in green hydrogen. Our goal is to strengthen research, train human resources, and lay the groundwork to establish an international joint laboratory in Vietnam focused on hydrogen by 2029.

Among the technical barriers that exist today, what factor determines the efficiency and feasibility of hydrogen technology, and what path do you see for Vietnam?

One of the key factors determining the efficiency and feasibility of hydrogen technology is the catalyst material. Currently, the most commonly used catalyst is platinum; a rare and expensive precious metal. It is estimated that if all existing cars were replaced by hydrogen fuel cell vehicles, the world’s known platinum reserves would be depleted within 50 years.

Our approach focuses on developing alternative, low-cost catalysts made from more abundant elements such as iron, cobalt, and nickel. These catalysts are designed based on the structural and functional understanding of natural enzymes like hydrogenase or nitrogenase, which are exceptional biological catalysts capable of producing hydrogen without platinum. We have demonstrated the functionality of these catalysts, though their efficiency remains lower than that of platinum. However, the clear advantage is their significantly lower cost, and the fact that Vietnam could be fully self-reliant in developing this technology.

Could you tell us about the progress your team has made, from materials research to the development of complete hydrogen technology components and devices?

Our work goes beyond materials research. We actively fabricate water electrolysis components, including “artificial leaves”, and conduct in-lab testing. When using commercial platinum catalysts, our devices can deliver a stable current for several months. However, when replaced with our own non-platinum materials, performance drops significantly within just a few hours. This is a harsh reality, but it also highlights the importance of continuous testing, as without this it is difficult to advance in the field.

We are also collaborating with Dr. Artero’s team at CEA to develop “artificial leaf” components, which mimic the natural function of leaves: absorbing sunlight and splitting water into hydrogen and oxygen. Through a novel technique we discovered, we simply immerse a solar panel in a special “magic solution”, which triggers the self-assembly of two catalyst layers onto each side of the panel, effectively transforming it into a fully functional artificial leaf. This technology has been recognized by CEA as a major breakthrough.

Building on this, we are now testing a “two-in-one” system that simultaneously splits water to generate hydrogen and reduces CO₂ into CO, paving the way for direct methanol production from solar energy. This opens up opportunities to store energy in liquid rather than gaseous form.

What do you see as the greatest challenges facing hydrogen technology development in Vietnam?

I can identify five core challenges.

First, the research community is small and lacks strong domestic links. Vietnam does not yet have a comprehensive hydrogen research ecosystem. Most research collaboration is international, and it is difficult to identify even ten specialized hydrogen research groups in the country.

Second, we face “brain drain”. While we have trained many high-quality professionals, most choose to continue their studies and research in countries like France, the US, Japan, or South Korea. International scholarship programs are highly attractive, while Vietnam still lacks compelling postgraduate funding schemes to encourage young talent to stay.

Third, our research infrastructure remains underdeveloped. For example, XPS (X-ray photoelectron spectroscopy), which is an essential tool in materials science, is still unavailable in Vietnam. As a result, we must send samples abroad for analysis, which not only raises concerns about data security and intellectual property but also limits our ability to control information about what we are working on.

Fourth, we lack a large-scale national research program. Current projects are fragmented and without a long-term vision. What we need is a sustained, high-level research investment program aimed at mastering hydrogen energy technologies.

And fifth, domestic enterprises still remain on the sidelines. Businesses often only become interested once a technology is market-ready. But without early-stage investment, there will be no product to commercialize. Research on solar cell technology, which we widely use today, began back in the 1960s. If we don’t start now, by the time hydrogen technology reaches maturity, Vietnam will once again be in a passive position, with no option but to purchase foreign technology.

As a scientist, what do you hope to see from policymakers and the business community?

Achieving technological self-reliance in renewable energy, especially hydrogen, is not merely a technical challenge, it’s a matter of vision, human capital, ecosystem building, and collaborative effort. If we start acting today, even with small steps, the future of hydrogen in Vietnam can move from a distant possibility to a tangible reality.