Here’s a Cost Effective Way to Make Green Hydrogen With an Unusual Ingredient

Researchers have used electrolysis to directly make low-cost hydrogen from urine. The process uses 25% less electricity than splitting water.

Human waste contains many valuable nutrients such as nitrogen, phosphorus and potassium. That makes it a promising potential fertilizer with a lower carbon footprint than today’s fertilizers.

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But human waste is also a promising source of untapped energy. And in the latest attempt to tap that energy, researchers have developed a low-cost, efficient way to produce clean hydrogen fuel from human urine. They present this work in the journal Nature Communications.

Hydrogen is a clean-burning fuel that has the potential to decarbonize shipping, aviation, and heavy industries. But it is mostly produced around the world by stripping it out of natural gas, releasing carbon dioxide in the process. The best way to make green hydrogen is to split water into hydrogen and oxygen, but this technology in turn requires large amounts of electricity.

As a cost-effective alternative, researchers have been looking at splitting urea to produce hydrogen, which requires much less energy than splitting water. However, pure urea is typically produced via the chemical Haber-Bosch process, which is also energy- and carbon-intensive.

So researchers from the Australian Research Council Centre of Excellence for Carbon Science and Innovation and the University of Adelaide came up with a way to use a free source of urea: human urine.The team has devised a method to produce hydrogen by directly splitting the urea in urine. Urine contains plenty of urea, but it also contains chloride ions, which cause unwanted chemical reactions during electrolysis. The reactions produce chlorine gas, which corrodes the electrodes and slows down the urea-splitting reaction, eventually damaging the setup.

As a solution, the researchers developed a system based on a different reaction mechanism. They use a platinum-based catalyst that soaks up chlorine gas on its surface. The adsorbed chlorine directly couples with urea to form chemical compounds that are then converted into nitrogen.

This reaction process speeds up urine electrolysis while avoiding chlorine-induced corrosion. The system works for over 200 hours at reduced voltage. As a result, it uses about 25% less electricity than water splitting systems. Now, the team plans to reduce cost further by finding a non-precious-metal catalyst since platinum is expensive.

Source: Pengtang Wang et al. Urine electrooxidation for energy–saving hydrogen generation. Nature Communications, 2025.