The global shipping industry accounts for a significant portion of greenhouse gas emissions, prompting MIT researchers to devise an innovative solution to create green hydrogen fuel for maritime use. By utilizing recycled aluminum from soda cans, seawater, and even caffeine, the researchers have demonstrated a practical and environmentally friendly method. One of the primary challenges with hydrogen fuel – aluminum impurities and storage safety – is effectively addressed by their approach. The study involves turning old soda cans into aluminum pellets treated with gallium or indium alloys for purification before reacting with seawater to produce hydrogen. To enhance the reaction rate, the researchers discovered that adding caffeine, specifically imidazole, significantly accelerates hydrogen production, making the process more efficient. Importantly, this method allows for the recovery and reuse of over 90 percent of the rare gallium-indium alloy, reducing costs and enhancing sustainability. With a focus on sustainability and scalability, the researchers aim to provide a solution that can be applied not only to maritime vessels but potentially to other transportation modes like trucks, trains, and airplanes. By eliminating the need to transport volatile hydrogen and using readily available seawater and recycled materials, the method offers a promising step towards reducing reliance on fossil fuels. The development of a reactor for on-demand hydrogen production on moving vessels further exemplifies the practicality and potential impact of this green hydrogen solution.