A clean energy transition is happening all over the world as the worsening climate crisis creates an urgent need to decarbonize energy systems.
Unlike fossil fuels like coal and oil, clean energy sources do not release huge amounts of greenhouse gases (GHG) like methane, CO2, nitrous oxide, or other pollutants during their production, contributing to a healthier environment.
Interestingly, clean energy can come from renewable sources like the sun which are constantly replenished and available all across the planet as well as non-renewable sources like nuclear energy, which makes use of finite resources (uranium).
Compared to their fossil fuel counterparts, clean energy sources also have lower maintenance and operating costs, which allows for more stable prices for consumers.
With that, the clean energy industry is fast-growing, with investment in cleantech technologies that reduce environmental impact and promote sustainability, reaching a record $71 billion in Q3 2024, as per Deloitte.
Now, when it comes to clean energy sources, here are the most prominent ones:
- Solar – The sun’s radiation is utilized here by leveraging technologies like photovoltaic (PV) panels that convert sunlight directly into electricity. In 2024, global solar capacity surged significantly, adding a notable 593 GW of solar PV capacity.
- Wind – Wind’s kinetic energy is converted into electricity by turbines. Depending on the location of the turbines, it can be of two types: onshore wind power, where wind farms are located on land, and offshore wind energy, where wind farms are located at sea.
- Water – The kinetic energy of flowing water is used to generate electricity, primarily through dams and turbines. Hydropower contributes about 15% to total electricity generation.
- Geothermal – This type of energy is harnessed through the internal heat of the earth and is obtained through geothermal power plants located in underground reservoirs.
- Biomass – Here, organic matter like crop waste and forestry residues is harnessed.
- Nuclear – It is the energy of an atom with power obtained from nuclear fission and nuclear fusion. As per Deloitte’s power and utilities survey, advanced nuclear technologies will play the most important role in meeting rising power demand in the next few years.
- Hydrogen – Hydrogen is produced from various resources and, when consumed in a fuel cell, produces only water. The US Department of Energy (DOE) has allocated $7 billion to develop hydrogen hubs.
Hydrogen as a Powerful Clean Fuel
The very first element in the periodic table, hydrogen (H), is a colorless, odorless, tasteless, highly combustible, and non-toxic gaseous substance. It is also the simplest, lightest, and most abundant element.
But what makes it extremely attractive is the fact that when burned, hydrogen only produces water vapor. When produced using renewable energy, in particular, green hydrogen can help decarbonize sectors like transportation and power generation.
Amidst the surging energy needs of society, hydrogen offers a highly efficient clean energy source that can potentially be produced from various sources. It is actually an energy carrier that can be used to move, store, and deliver energy produced from other sources.
Now, the most common ways to produce hydrogen fuel are:
- Thermal Process – Produced using a high-temperature process called steam reforming, hydrogen is generated when steam reacts with hydrocarbon fuels such as natural gas, diesel, gasified coal, gasified biomass, and renewable liquid fuels.
- Electrolytic Process – Water (H2O) is separated into oxygen and hydrogen using an electric current. The process takes place inside an electrolyzer, where electricity passes through water, causing the molecules to separate.
- Solar-driven Process – Light is used to produce hydrogen and includes different approaches, such as photobiological, photoelectrochemical, and solar thermochemical.
- Biological Process – Hydrogen is produced through biological reactions using microbes like bacteria and microalgae.
Now, hydrogen has a very high potential to serve society’s clean energy needs, but the problem is that there are still challenges that need to be overcome. These challenges include achieving mass production, transportation, and storage. Also, hydrogen production needs to be stable and inexpensive.
Hydrogen evolution reaction (HER) is considered the most environmentally friendly and sustainable hydrogen production method. It is a cathodic reaction that involves the electrolysis of water.
In this electrochemical process of water splitting, the likes of platinum, nickel, and other transition metals are used as catalysts that reduce protons to hydrogen gas.
The problem here arises with the metal most commonly used for catalysts, platinum, which, while offering highly efficient catalytic performance, faces the issues of rarity and cost. Hence, there is a growing focus on alternative catalysts to minimize the consumption of precious metals.
Platinum’s Role in Making Hydrogen Clean
A shiny, silvery-white metal that sometimes gets mistaken for silver, platinum (Pt) is key to achieving the goal of net zero emissions. This dense, malleable, and lustrous metal is highly unreactive and resistant to corrosion, even at high temperatures.
However, it is an extremely rare metal, over 30 times rare than gold, occurring at a concentration of only 0.005 ppm in Earth’s crust. As a scarce metal, platinum is difficult and costly to mine, which means a more expensive end product.
The metal is primarily mined in South Africa, which accounts for over 70% of global platinum supplies, along with Russia, Zimbabwe, Canada, and the US.
When it comes to use cases, platinum is used to make jewelry, but most importantly, it is utilized in electronic components and catalytic converters to reduce transport emissions. In 2022, around 85 tonnes of the metal was used just for catalytic converters. It is also emerging as a critical mineral in the global energy transition.
The metal is particularly invaluable in electrolyzers, which are of various types, but hydrogen project developers favor proton exchange membrane (PEM) electrolysis. A more efficient alternative to alkaline electrolysis, PEM electrolyzers use platinum to make extremely high-performance catalysts.
Platinum is also used in PEM fuel cells, which operate like PEM electrolyzers but in reverse. Instead of separating hydrogen and oxygen, it combines them using platinum as a catalyst.
Hydrogen fuel cells are made of two electrodes — an anode (negative electrode) and a cathode (positive electrode) with an electrolyte separating the two. A catalyst, which is a layer of metal like platinum, at the anode splits hydrogen molecules into protons and electrons, which move toward the cathode to create a flow of electricity.
The excellent conductivity and chemical stability of platinum are what make it so highly efficient as a catalyst. Their efficiency is key to achieving high energy conversion rates in fuel cells, allowing them to compete with traditional energy sources.
As the need for decarbonization continues to rise, demand for platinum is expected to rise thanks to the platinum-based PEM technologies boasting the potential to achieve 11% of global carbon dioxide emissions reductions.
Hence, there is a growing focus on this metal across the world. In the US, the Inflation Reduction Act includes a tax benefit for low-carbon hydrogen with the aim of accelerating clean hydrogen production and fuel cell EV adoption. The REPowerEU by the European Commission meanwhile aims to double its capacity of clean hydrogen to 80 GW by 2030.
This global push, according to the World Platinum Investment Council, can make clean hydrogen production the largest source (35%) of platinum demand by 2040.
Besides the imbalanced demand-supply dynamics, the use of precious metals like platinum poses further challenges, such as high costs, potential degradation, and environmental concerns. As a result, researchers have been continuously working on ways to remove platinum as a hydrogen catalyst and find better alternatives.
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Making Platinum-free Catalysts
In the pursuit of platinum-free hydrogen, researchers from UNSW Sydney are conducting a study to address the issues associated with the use of the precious metal in hydrogen fuel cells.
The researchers developed a new technique to understand why some catalyst materials have less stability than Pt, which will help other researchers develop new materials and enhance the future prospects of platinum-free catalysts in hydrogen fuel cells.
The techniques developed revealed that as much as 75% of the iron-based active sites in the fuel cell became inactive in the first 10 hours of operation. This was largely because of the loss of iron active sites, with carbon corrosion being another reason.
In a separate study1, researchers from the University of Wisconsin-Madison, Cornell University, and Wuhan University discovered a new way of catalyzing the reaction to make hydrogen fuel cells.
The researchers used cheap, non-precious metal nickel for both the cathode and anode electrodes of the fuel cell. The nickel-based electrocatalyst was designed with a 2-nanometer shell made of nitrogen-doped carbon.
Embedding single nickel atoms in a graphene-like sheath made of carbon and nitrogen atoms made them resistant to oxidation and bonded hydrogen atoms with the ideal strength needed for an effective hydrogen oxidation reaction (HOR).
So, with an anode catalyst of a solid nickel core encased in a carbon shell and a cathode of cobalt-manganese, researchers created a hydrogen fuel cell free of any precious metal with an output over 200 mW/cm².
Back in 2020, scientists at the DOE’s Argonne National Laboratory meanwhile found and developed the most promising platinum-free catalyst for hydrogen fuel cells that rely on the oxygen reduction reaction (ORR). It was based on iron, nitrogen, and carbon, which were mixed and heated between 900 and 1100 degrees Celsius in pyrolysis.
Then, the material’s iron atoms were bonded with nitrogen atoms and embedded in graphene. Here, each iron atom constitutes a site at which the ORR can occur, hence making the electrode more efficient.
Amidst this increased interest in reducing the reliance on expensive platinum and improving the efficiency and cost-effectiveness of hydrogen fuel cells and electrolysis, scientists have now developed a palladium-based nanosheet catalyst whose performance is on par with platinum in hydrogen production.
Palladium as an Alternative to Platinum for Affordable Hydrogen
The latest2 study came from the Tokyo University of Science (TUS) researchers who have developed a novel hydrogen evolution catalyst, bis(diimino)palladium coordination nanosheets (PdDI).
Palladium is a shiny, silvery, and one of the most abundant platinum group metals with a density much less than platinum.
The use of palladium, which offers platinum-like efficiency at a fraction of the cost, paves the way for affordable and sustainable hydrogen production to accelerate the clean energy revolution.
Led by Professor Hiroshi Nishihara and Dr. Hiroaki Maeda from TUS in partnership with researchers from other institutes, the study marks a breakthrough in the hydrogen evolution reaction (HER) technology.
The HER catalyst electrodes facilitate the conversion of H, which is produced at the electrode surface during water splitting, into hydrogen gas (H2). To overcome the limitations of Pt that restrict its large-scale application as a HER catalyst, the team offers a highly efficient alternative for platinum catalysts using a simple synthesis process.
The team created palladium-based nanosheets that have the ability to achieve elevated catalytic activity with reduced precious metal usage, which significantly lowers the costs of H2 production.
As Dr. Maeda noted, “developing efficient HER electrocatalysts is key to sustainable H2 production” and “Bis(diimino)metal coordination nanosheets, with their high conductivity, large surface area, and efficient electron transfer, are promising candidates.” In addition to these properties, the sparse metal arrangement of the nanosheets reduces the material usage.
The PdDI nanosheets viz. E-PdDI and C-PdDI were successfully developed using two different methods:
- Electrochemical oxidation
- Gas-liquid interfacial synthesis
Once activated, the E-PdDI sheets demonstrated a low overpotential of 34 mV, which means little extra energy is required for hydrogen production. It not only matches the overpotential of platinum, which is 35 mV, but also the precious metal’s catalytic performance with the exchange current density of 2.1 mA/cm².
The “remarkable performance” surpasses not only that of Pd metal electrodes but also conventional MDI (M=Ni, Co, Cu) nanosheets, the study noted, adding that this exceptional performance was achieved despite using very small amounts of precious metals.
With these results, E-PdDI presents the most efficient HER catalysts developed to date, making it a promising low-cost alternative to platinum.
When it comes to long-term stabilities, which is one of the critical aspects of any catalyst, the PdDI nanosheets also exhibited excellent durability. They remained intact after 12 hours in acidic conditions, validating their applicability for real-world hydrogen production systems.
“Our research brings us one step closer to making H2 production more affordable and sustainable, a crucial step for achieving a clean energy future.”
– Dr. Maeda
By reducing the reliance on scarce and costly platinum, bis(diimino)palladium coordination nanosheets (PdDI) also align with the UN’s Sustainable Development Goals (SDGs), promoting affordable and clean energy as well as innovation and infrastructure.
Notably, the study isn’t restricted to laboratory experiments. The cost-effectiveness, scalability, and enhanced activity of PdDI nanosheets make them extremely useful in large-scale energy storage systems, hydrogen fuel cells, and industrial hydrogen production.
Moreover, PdDI could reduce mining-related emissions associated with platinum-based catalysts, accelerating the transition to a sustainable hydrogen economy. The next step for the TUS team is to optimize PdDI nanosheets for real-world use.
Click here to learn all about investing in Palladiu
Investable Innovative Companies
Let’s now take a look at a prominent name in the field that is helping advance clean energy technologies, including the development of platinum-free hydrogen catalysts.
Plug Power Inc. (PLUG -0.6%)
The $1.54 billion market cap company specializes in hydrogen fuel cell systems and has been researching non-platinum catalysts to reduce costs and improve efficiency.
As of writing, PLUG shares are trading at $1.71, down 21.6% YTD. Its EPS (TTM) is -2.54, and the P/E (TTM) is -0.65.
Plug Power Inc. (PLUG -0.6%)
For Q4 2024, Plug Power reported $191.5 million in revenue and a gross margin loss of 122%, while operating cash flow improved by 46% YoY. It closed the year with over $200 million in unrestricted cash. The company recently closed a $1.66 bln DOE Loan Guarantee program.
During this period, Plug Power’s electrolyzer business continued to scale, and the hydrogen business strengthened.
“2024 was a year of strong execution and meaningful strategic progress for Plug as we advanced our initiatives and made strides in driving the hydrogen economy forward.”
– CEO Andy Marsh
Latest on Plug Power
Conclusion
With the world population growing fast, which is expected to rise to approximately 10.3 billion by the mid-2080s, the problem of greenhouse gas emissions is going to become even more severe. This creates a need to cut our reliance on fossil fuel energy and adopt energy sources that are clean, safer, abundant, and environment-friendly.
Here, hydrogen energy has emerged as a key driver of a clean and sustainable future, offering a zero-emission alternative to fossil fuels. While promising, the large-scale production of hydrogen relies heavily on expensive platinum-based catalysts, which makes cost a big challenge for the industry.
By replacing precious Pt metal with PdDI nanosheets, the latest study has achieved a breakthrough in the cost-effective production of electrodes and produced great outcomes in electrode-supplying industries, hydrogen production, and automobiles.
Click here for a list of top clean energy stocks with environmental focus.
Studies Referenced:
1. Gao, Y., Yang, Y., Schimmenti, R., Murray, E., Peng, H., Wang, Y., Ge, C., Jiang, W., Wang, G., DiSalvo, F. J., Muller, D. A., Mavrikakis, M., Xiao, L., Abruña, H. D., & Zhuang, L. (2022). A completely precious metal–free alkaline fuel cell with enhanced performance using a carbon-coated nickel anode. Proceedings of the National Academy of Sciences, 119(13), e2119883119. https://doi.org/10.1073/pnas.2119883119
2. Maeda, H., Phua, E. J. H., Sudo, Y., Nagashima, S., Chen, W., Fujino, M., Takada, K., Fukui, N., Masunaga, H., Sasaki, S., Tsukagoshi, K., & Nishihara, H. (2024). Synthesis of Bis(diimino)palladium Nanosheets as Highly Active Electrocatalysts for Hydrogen Evolution. Chemistry – A European Journal. https://doi.org/10.1002/chem.202403082