People are increasingly interested in hydrogen as a sustainable energy source. However, they recognize the associated production methods still have room for improvement regarding their impact on the planet. For example, hydrogen is vital for ammonia production, but facilities still use fossil fuels to make it. Similarly, other manufacturing methods involving hydrogen require rare metals that are expensive or in short supply.
However, researchers at Japan’s RIKEN Center for Sustainable Resource Science became interested in making hydrogen production more sustainable by extracting it from water and using renewable energy during the process. Here is a look at what they accomplished.
Learning From Past Efforts
Scientists have developed various hydrogen production processes. However, these researchers focused on electrolysis. This process requires an electrolyzer that creates hydrogen from water molecules. The RIKEN team clarified that electrolysis is yet to be sustainable because the required catalysts are hard to source, necessitating the continued dependence on fossil fuels during production.
An ideal catalyst must be highly active and tolerate harsh acidic environments. The most commonly used metal catalysts are platinum and iridium, but they’re increasingly less prevalent. Unfortunately, more abundant metals such as nickel are not active enough and dissolve quickly when exposed to the electrolyzer’s environment.
The researchers looked for a better catalyst by focusing on mixed cobalt and manganese oxides. They thought that would give them the best of both worlds since those substances alone don’t provide the desired characteristics. More specifically, cobalt oxides are sufficiently active but corrode too quickly when subjected to the electrolyzer’s acidity. Then, manganese oxides are more stable in that environment but are not active enough.
The team also recognized the target current density must be about 10 to 100 times higher in their experiments to meet the needs of industrial-scale hydrogen production. They mentioned the high currents used in previous experiments caused numerous problems, including the breakdown of the catalysts, necessitating specific preparations this time around.
Eventually, the researchers achieved their ideals by inserting cobalt oxide into the spinal lattice of manganese. Doing that created mixed cobalt manganese oxide, a stable catalyst.
Trial and Error Necessary
People often learn to improve by trying certain options and monitoring the outcomes. For example, mountaintop removal has covered more than 2,000 streams in the Appalachian area, leading some professionals to consider other options. No-till farming offers a more uplifting case. It became popular as more agricultural professionals realized reducing soil disturbance is vital in keeping the land healthy and productive.
The RIKEN researchers went through periods of substantial trial and error as they considered the shortcomings of various metals and worked to overcome those obstacles. Fortunately, lab tests showed the hard work and forethought paid off. The new catalyst’s activation level was close to that of advanced iridium oxides. Plus, its current density remained at 200 milliamperes per square centimeter for more than two months. That suggests it has practical uses outside the laboratory.
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Experimentation Brings Progress
The researchers’ work in creating hydrogen from water could bring about significant changes in the production of fuel cells and agricultural fertilizers. It is also essential that people keep exploring alternatives, as this team did. Recognizing that there is room for improvement is an excellent way to keep science moving forward and serve as the vehicle through which people find sustainable options to use now and into the future.
Jane Marsh, Contributor
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