Scientists develop eco-friendly method to make hydrogen using solar power and agricultural waste

Associate Professor Meenesh Singh, right, and postdoctoral researcher Rohit Chauhan work in Singh’s laboratory at the University of Illinois Chicago. Credit: enny Fontaine/ UIC.

Engineers at the University of Illinois Chicago (UIC) have created a groundbreaking method to produce hydrogen gas using only solar power and agricultural waste, such as manure or husks.

This innovative process reduces the energy needed to extract hydrogen from water by 600%, opening up new possibilities for sustainable and eco-friendly chemical production.

Hydrogen-based fuels are considered one of the best sources of clean energy.

However, producing pure hydrogen gas traditionally requires large amounts of electricity, often generated from coal or natural gas, making it an energy-intensive process.

A team led by UIC engineer Meenesh Singh has developed a new process for green hydrogen production, detailed in a paper published in Cell Reports Physical Science.

This method uses a carbon-rich substance called biochar to significantly reduce the amount of electricity needed to convert water into hydrogen.

By utilizing renewable energy sources like solar power or wind and capturing byproducts for other uses, the process can achieve net-zero greenhouse gas emissions.

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

The process of electrolysis, which splits water into hydrogen and oxygen, usually requires a substantial electric current. On an industrial scale, this electricity is typically generated using fossil fuels.

Scientists have recently reduced the voltage needed for water splitting by adding a carbon source to the reaction.

However, this process still relies on coal or expensive chemicals and releases carbon dioxide as a byproduct.

Singh and his team improved this method by using biomass from common waste products instead. By mixing sulfuric acid with agricultural waste, animal waste, or sewage, they create a slurry-like substance called biochar, rich in carbon.

The team experimented with various types of biochar made from sugarcane husks, hemp waste, paper waste, and cow manure.

When added to the electrolysis chamber, all five biochar varieties lowered the power needed to convert water to hydrogen. Cow dung proved to be the most effective, reducing the electrical requirement sixfold to about a fifth of a volt.

The energy needs were so low that the researchers could power the reaction with a standard silicon solar cell, generating roughly 15 milliamps of current at 0.5 volts. This is less power than what an AA battery produces.

“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 achieve net-zero emissions, the process must capture the carbon dioxide generated by the reaction.

Singh suggests 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 method not only diversifies the use of biowaste but also enables the clean production of various chemicals beyond hydrogen,” said UIC graduate Nishithan Kani, co-lead author of the paper.

“This cost-effective way of making hydrogen could help farmers become self-sustainable for their energy needs or create new revenue streams.”

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

In addition to Singh, Kani, and Chauhan, the paper’s co-authors include UIC graduate student Rajan Bhawnani, as well as researchers from Stanford University, Texas Tech University, the Indian Institute of Technology Roorkee, Korea University, and Orochem Technologies Inc.