Innovative Technique Produces Hydrogen Using Solar Power and Agricultural Waste

Engineers at the University of Illinois Chicago have developed a groundbreaking method to produce hydrogen gas from water using only solar power and agricultural waste, such as manure or husks. This innovative approach reduces the energy needed to extract hydrogen from water by 600%, paving the way for more sustainable, climate-friendly chemical production.

Hydrogen-based fuels are among the most promising sources of clean energy. However, the production of pure hydrogen gas typically requires substantial energy input, often derived from coal, natural gas, and large amounts of electricity.

In a paper published in Cell Reports Physical Science, a multi-institutional team led by UIC engineer Meenesh Singh introduces this new green hydrogen production process.

The method employs a carbon-rich substance called biochar to significantly reduce the electricity needed for water electrolysis—the process of splitting water into hydrogen and oxygen. By utilizing renewable energy sources like solar or wind power and capturing byproducts for other applications, the process can achieve net-zero greenhouse gas emissions.

“We are the first group to show that you can produce hydrogen utilizing biomass at a fraction of a volt,” said Singh, an associate professor in the department of chemical engineering. “This is a transformative technology.”

Electrolysis requires an electric current, and industrial-scale production typically relies on fossil fuels to generate the necessary electricity.

Recent scientific advancements have lowered the voltage required for water splitting by adding a carbon source to the reaction. However, this process still uses coal or expensive chemicals and emits carbon dioxide as a byproduct.

Singh and his team modified this process by using biomass from common waste products. By mixing sulfuric acid with agricultural waste, animal waste, or sewage, they created a carbon-rich slurry called biochar.

The researchers tested various types of biochar derived from sugarcane husks, hemp waste, paper waste, and cow manure. Each type of biochar significantly reduced the power needed to convert water to hydrogen, with cow dung performing the best by reducing the electrical requirement sixfold to about a fifth of a volt.

The energy requirements were low enough for the researchers to power the reaction with a single standard silicon solar cell, generating roughly 15 milliamps of current at 0.5 volts—less than the power produced by an AA battery.

“It’s very efficient, with almost 35% conversion of the biochar and solar energy into hydrogen,” said Rohit Chauhan, a co-author and postdoctoral scholar in Singh’s lab. “These are world record numbers; it’s the highest anyone has demonstrated.”

To make the process net-zero, the carbon dioxide generated by the reaction must be captured. Singh noted that this could have additional environmental and economic benefits, such as producing pure carbon dioxide for carbonating beverages or converting it into ethylene and other chemicals used in plastic manufacturing.

“This approach not only diversifies the utilization of biowaste but also enables the clean production of various chemicals beyond hydrogen,” said UIC graduate Nishithan Kani, co-lead author on the paper. “This inexpensive method of making hydrogen could help farmers become self-sustainable for their energy needs or create new revenue streams.”

Orochem Technologies Inc., which sponsored the research, has filed patents for their biochar and hydrogen production processes. The UIC team plans to scale up and test these methods on a larger scale.

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