Artificial photosynthesis could one day provide clean energy
Researchers at Monash University in Melbourne have been testing a new process called electrochemical water splitting, using commercial solar cells to generate hydrogen and oxygen by passing an electric current through water, creating hydrogen fuel. The machine used in testing produces hydrogen fuel using an artificial version of photosynthesis (replicating the same process plants and bacteria use), increasing energy efficiency. The energy efficiency level measures how much solar energy is obtained as chemical energy in the form of hydrogen, in plants this level is between 1% and 2%, however the research team have managed to produce 22% through their machine, breaking a previous world record of 18%.
The race is on to find a new way to power the world free from polluting fossil fuels, and a group of Australian scientists think they've found an option.

A solar-powered device developed by researchers at Monash University in Melbourne is replicating what plants and bacteria do with photosynthesis. Although it doesn't resemble a leaf exactly, it should be almost as environmentally friendly.

"We're effectively trying to carry out photosynthesis artificially, and much more efficiently than plants do," Professor Doug MacFarlane, leader of the Energy Program of the ARC Centre of Excellence for Electromaterials Science at Monash University, told Mashable Australia.

In a process called electrochemical water splitting, the scientists use commercial solar cells to generate hydrogen and oxygen by passing an electrical current through water. The process creates a hydrogen fuel, which is a much cleaner, sustainable form of energy than those that involve carbon because it creates no carbon dioxide.

Credit: Monash University

With their machine, the researchers have recently set a new energy efficiency world record for solar fuels. The machine can produce hydrogen fuel using an artificial version of photosynthesis at more than 22% energy efficiency, surpassing the previous record of 18%. In most plants, the energy efficiency level is typically between 1% and 2%, he said.

The energy efficiency calculation measures how much solar energy is ultimately obtained as chemical energy in the form of hydrogen.

The researchers have set this new record by employing nickel electrodes to split the water, a more affordable alternative to the precious metal catalysts that were used formally.

MacFarlane predicted that with further advances, their system could one day be found on roofs around the world. The solar-electric section and water electrolysis cell could eventually look similar to a traditional solar hot water heater, he said. Alternatively, the water splitting equipment could be housed in a basement or inside a wall.

The future possibilities for commercial use of these new forms of clean energy are ultimately down to competition and cost, MacFarlane said. "The price of fossil fuels is a big factor in answering these questions," he added. "While electricity prices remain historically low, then it's a tough price target for a technology like this to match."

In the meantime, the scientists are focusing on making their machine more and more energy efficient. "I would predict that 22% is going to be surpassed quite soon," MacFarlane said. "The fundamentals that we've uncovered here will allow us and others to do better ... within the year, I think 30% is within the realm of possibility."

The findings were published in the journal, Energy and Environmental Science(opens in a new tab).