‘Transformative’ new solar technology turns manure into hydrogen fuel

UIC engineers have introduced a breakthrough method of producing hydrogen using solar energy and agricultural waste, drastically reducing energy consumption and enabling net zero greenhouse gas emissions.

Engineers at the University of Illinois at Chicago have developed a novel method of producing hydrogen gas from water using only solar energy and agricultural byproducts such as manure and chaff. This technique reduces the energy needed to extract hydrogen from water by 600%, paving the way for more sustainable and environmentally friendly chemical production.

Hydrogen-based fuels are one of the most promising sources of clean energy. However, producing clean hydrogen is an energy-intensive process, often requiring coal or natural gas and large amounts of electricity.

Innovative approach of UIC engineers

In an article for Mobile reports Physical sciencea multi-institutional team led by UIC engineer Meenesh Singh presents a new process for producing green hydrogen.

This method uses a carbon-rich substance called biochar to reduce the amount of electricity needed to convert water into hydrogen. By using renewable energy sources such as solar or wind energy and capturing byproducts for other uses, the process can reduce greenhouse gas emissions to net zero.

“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. “It’s a revolutionary technology.”

Redefining electrolysis with biochar

Electrolysis, the process of splitting water into hydrogen and oxygen, requires electricity. On an industrial scale, fossil fuels are usually needed to generate this electricity.

Recently, scientists lowered the voltage required to split water by introducing a carbon source into the reaction. However, the process also uses carbon or expensive chemicals, and the byproduct is carbon dioxide.

Singh and colleagues modified this process to use biomass from regular waste instead. By mixing sulfur acid with agricultural waste, animal waste or sewage they form a sludge-like substance called biochar, which is rich in carbon.

The team experimented with different types of biochar made from sugar cane husks, hemp waste, paper waste and cow dung. When added to the electrolysis chamber, all five varieties of biochar reduced the power needed to convert water to hydrogen. The best of them, cow dung, reduced electricity demand sixfold, to about one-fifth of a volt.

Achievements and plans for the future

The energy requirement was low enough that researchers could power the reaction using a single standard silicon solar cell producing about 15 milliamps of current at 0.5 volts. This is less than the amount of energy produced by an AA battery.

“It is very efficient, converting biochar and solar energy to hydrogen by almost 35%,” said Rohit Chauhan, co-author and graduate student in Singh’s lab. “These are world records; that’s the highest anyone has ever shown.”

For a process to be net zero, it must capture the carbon dioxide produced in the reaction. But Singh said it could also have environmental and economic benefits, such as producing pure carbon dioxide to fuel carbonated drinks or converting it into ethylene and other chemicals used in plastic production.

“It not only diversifies the use of bio-waste, but enables the clean production of chemicals other than hydrogen,” said UIC graduate student Nishithan Kani, co-author of the paper. “This cheap way of producing hydrogen could enable farmers to become self-sufficient in their energy needs or create new sources of income.”

Reference: “Subvoltage conversion of activated biochar and water to near-equilibrium H2 production via biochar-assisted water electrolysis” Nishithan C. Kani, Rohit Chauhan, Samuel A. Olusegun, Ishwar Sharan, Anag Katiyar, David W. House, Sang-Won Lee, Alena Jairamsingh, Rajan R. Bhawnani, Dongjin Choi, Adam C. Nielander, Thomas F. Jaramillo, Hae-Seok Lee, Anil Oroskar, Vimal C. Srivastava, Shishir Sinha, Joseph A. Gauthier and Meenesh R. Singh, May 30, 2024 r., Cell Reports Physical Sciences.
DOI: 10.1016/j.xcrp.2024.102013

Orochem Technologies Inc., which sponsored the research, has filed a patent application for its biochar and hydrogen production processes, and the UIC team plans to test these methods on a large scale.

In addition to Singh, Kani and Chauhan, UIC student Rajan Bhawnani co-authored the paper. Other co-authors are from Stanford University, Texas Tech University, Indian Institute of Technology Roorkee, Korea University and Orochem Technologies Inc.