Photosynthesis, the natural process by which plants convert sunlight and inorganic matter into carbonates and oxygen, has long served as an inspiration for renewable energy research.

Despite its crucial role in sustaining life on Earth, the efficiency of natural photosynthesis is relatively low (~1%) due to the inherent limitations of biological organisms. To overcome this limitation, researchers have developed a chloroplast-mimicking Artificial Photosynthetic Cell (APC), which operates under mild conditions and achieves a solar energy conversion efficiency of 3.1%.

In a study published in Angewandte Chemie International Edition, Prof. WANG Yaobing and Dr. ZHOU Enbo from Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, introduced an innovative APC design based on a molecular biomimetic thylakoid, CoTPP-FePy, capable of splitting water into hydrogen (H2) and oxygen (O2) at a low driving voltage of 1.1 V (< 1.23 V)and near-neutral pH (≈7).

The researchers synthesized CoTPP-FePy, which combines cobalt-porphyrin (Co-TPP) as water oxidation active site with covalently linked iron-pyridine (FeIII/FeII-Py) shuttles as electron scavengers. Emulating the light reactions in natural thylakoid membranes, CoTPP-FePy effectively integrates light harvesting, photocatalysis, and electron/energy storage processes. Under illumination, the CoTPP-FePy exhibits fast intermolecular charge transfer (580 fs) along with an extended excited state lifetime (>6.1 ns), effectively energizing the FeIII-Py shuttles into FeII-Py and driving the water oxidation process at a rate of 35.5 μmol h-1.

Furthermore, the researchers developed a novel photoelectrochemical water-splitting flow system that interfaces the light-driven process and thermochemical reactions. In the subsequent dark reaction mimic, the Pt-modified membrane-electrode assembly (MEA) drives hydrogen production, completing the electron/energy transfer cycle via the FeIII/FeII-Py shuttles.

This study presents a fully chloroplast-mimicking approach that not only broadens the scope of biomimetic chemistry but also provides a promising and efficient pathway for solar energy utilization.

Schematic diagram of Natural photosynthesis and artificial photosynthetic cell (APC). (Image by Prof.WANG’s group)

Contact:

Prof. WANG Yaobing

Fujian Institute of Research on the Structure of Matter

Chinese Academy of Sciences

Email: wangyb@fjirsm.ac.cn