Scientists Design Catalyst That Mimics Z-Scheme in Photosynthesis


Chemists at the University of Kentucky and the Institute of Physics Research of Mar del Plata in Argentina have recently reported discovering a new way to trigger a critical step in the process of photosynthesis. This means the task could be used to develop new technologies to reduce carbon dioxide levels.

The researchers worked with a synthetic nanomaterial which combines the reductive power of cuprous oxide (Cu2O), with a layer of oxidizing titanium dioxide (TiO2). The nanomaterial prevents the loss of copper ion in the catalyst.

Scientists Design Catalyst That Mimics Z Scheme in Photosynthesis

The catalyst is comprised of Cu2O/TiO2 and has the ability to transfer electrons, meaning it can reduce atmospheric greenhouse gas levels (CO2) while simultaneously breaking apart the molecule of water (H2O). The distinct catalyst transfer mimics the natural “Z-scheme” transfer mechanism from photosynthesis. If the catalyst is exposed to sunlight, the electrons are then transferred to CO2 in a process which mimics the way photosystems operate naturally in both 1 and 2.

“Developing the materials that can be combined to reduce CO2 through a direct Z-scheme mechanism with sunlight is an important problem,” said Ruixin Zhou, doctoral student at UK College of Arts and Sciences. “However, it is even more difficult to demonstrate the process actually works. From this scientific viewpoint, the research is contributing to advance feature technology for carbon sequestration.”

Scientists Design Catalyst That Mimics Z Scheme in Photosynthesis

While a variety of materials could be used for the catalyst, the key discovery from this research is that the catalyst need not be made of scarce and expensive elements such as iridium or rhenium to create the reactions associated with sunlight reaching the Earth’s surface. The catalyst instead used corrosion resistant TiO2 to form a protective white coating to the octahedral particles of red Cu2O.

The calculated carbon monoxide (CO) construction from the CO2 reduction, the formation of oxygen (O2) via the H2O oxidation process, and the characterized electronic properties of the catalyst and components confirmed the proposed Z-scheme was operational.

The next goal for the researchers is to improve the Z-scheme process by exploring a series of different catalysts and determining the most efficient one that would convert the CO2 into chemical fuels like methane. If successful, it may pave the way for new technologies to be created, allowing a clean and affordable source of energy, and facilitating the reduction of greenhouse gases and fossil fuel emissions.