The quest for sustainable energy storage solutions remains a pressing challenge as the world pivots towards greener alternatives. In recent research emerging from the Leibniz Institute for Catalysis (LIKAT) in Rostock and the company H2APEX, scientists have made significant strides in the safe and stable storage of hydrogen. This volatile but essential gas has been identified as a critical player in achieving a successful energy transition, and the new approach discussed in their study published in *Nature Communications* highlights a promising methodology to facilitate this objective.
Central to this innovative approach is the development of a homogeneous catalyst system that chemically binds hydrogen gas (H2) with potassium bicarbonate. Bicarbonate, commonly recognized as an ingredient in baking powder, reacts with hydrogen in the presence of a ruthenium-based catalyst to produce formate, a benign salt derived from formic acid. This achievement not only illustrates a novel implementation of familiar chemical processes but also emphasizes the potential for leveraging readily available materials to address contemporary energy concerns.
Dr. Rui Sang and Ph.D. student Carolin Stein, who are the main authors of the study, articulate the system’s inherent reversibility—an essential feature allowing for the release of stored hydrogen at any given time, using the same catalyst material. This reversible reaction presents a significant advantage in managing hydrogen energy systems, enabling efficient toggling between storage and energy release based on demand.
The reaction described operates effectively at moderate temperatures (around 60°C), facilitating a practical implementation in real-world settings. According to Dr. Henrik Junge, the leader of the research team, the entire process occurs within a solution containing all essential chemical components, ensuring that the operations can be easily monitored and adjusted. The ability to modulate pressure to control hydrogen binding or release further enhances the system’s versatility, making it suitable for diverse applications.
In comparison to other proposed hydrogen storage mediums, such as methanol, ammonia, or methane, the formate developed in this study boasts a substantial safety profile; both in terms of human toxicity and energy consumption during the handling process. The ease with which formate can be stored—akin to how one might transport milk or beer—positions it as a more practical option for storage and transportation in everyday scenarios.
As discussions around hydrogen’s role in renewable energy and local energy ecosystems continue to gain momentum, the use of the potassium bicarbonate-formate system offers a viable solution, particularly in rural settings. Here, surplus renewable energy generated from wind or solar sources could be converted into hydrogen through electrolysis, which can then be stored in formate to balance energy supply and demand more efficiently.
The research collaboration aims to maximize hydrogen storage capacity within formate by exploring various parameters such as storage density and solubility. The choice to employ potassium as a counter ion stems from extensive testing and evaluation of potential candidates, culminating in a balanced approach that optimizes both performance and safety.
A CO2-Neutral Process for Clean Energy
A noteworthy aspect of this hydrogen storage process is its CO2-neutral nature. Traditional methods often result in the release of CO2 during hydrogen recovery; however, this new system effectively captures and retains CO2, preventing its release into the atmosphere. The capacity to produce pure hydrogen directly from formate without needing further purification presents a substantial benefit, particularly concerning applications within fuel cells.
Carolin Stein emphasizes the effectiveness of this innovative approach, detailing how over a span of six months, their team successfully maintained a high purity level (99.5%) of hydrogen through 40 consecutive cycles of storage and release, all while employing minimal amounts of catalyst.
Building on the promising results from their laboratory work, H2APEX is now venturing into creating a larger demonstrator system tailored for industry applications. Collaborations with technical research institutes aim to expedite this process with commercialization efforts expected to unfold by the end of 2025.
The researchers at LIKAT and H2APEX have opened new avenues for the safe and efficient storage of hydrogen, crucial in navigating the impending energy transition. As hydrogen is labeled as not just a chemical element but also a symbol of hope for sustainable energy solutions, it exemplifies the significant potential embedded within innovative scientific research and practical applications.