Urine-powered systems promise cheaper green hydrogen: study

CANBERRA, May 10 (Xinhua) -- Researchers have developed two innovative, energy-efficient systems that use urea from human urine and wastewater to produce cheaper green hydrogen, the University of Adelaide has said.

The systems offer a cheaper and more sustainable alternative to conventional methods for generating clean hydrogen while turning waste into a valuable energy resource, a press release of the university said on Friday.

Hydrogen is typically generated by splitting water through electrolysis, a process that is costly and energy-intensive. While extracting hydrogen from fossil fuels is cheaper, it comes with high carbon emissions, it said.

By contrast, using urea, particularly from urine, requires 20 to 27 percent less electricity and avoids the environmental impact of traditional methods, said the Australian Research Council Center of Excellence for Carbon Science and Innovation (COE-CSI) Chief Investigator Zheng Yao.

The researchers' first system uses a novel copper-based catalyst in a membrane-free setup to extract hydrogen from pure urea.

Their second system takes it a step further by using urine as a readily available and eco-friendly alternative source. It employs a chlorine-mediated oxidation mechanism with platinum-based catalysts to tackle chloride ions in urine, which can corrode the electrolysis system.

Both systems address a major drawback of existing urea-based approaches: they avoid producing toxic nitrates and nitrites, instead releasing harmless nitrogen gas, said COE-CSI Deputy Director and Chief Investigator Qiao Shizhang.

The team, led by Zheng and Qiao, both from the School of Chemical Engineering of the University of Adelaide, now aims to replace the costly platinum with non-precious, carbon-supported metal catalysts to further reduce costs and support sustainable hydrogen production. ■