Hawaii Convention Center

Mechanism of CO₂ Reduction by Molecular Catalysts in Water

Department of Chemistry, Faculty of Science, Kyushu University

Global warming is giving serious damages to our planet by causing various exceptional life-threatening disasters, such as heavy rain, flood, landslides, heat waves, droughts, wildfires, and so forth. Technological innovations capable of decreasing the atmospheric greenhouse gases and achieving the sustainable carbon-neutral energy cycles are the urgent demands to overcome. Besides our extended studies on photocatalytic hydrogen and oxygen evolution from water, we reported on the effective catalytic performances of cobalt porphyrins in selective catalytic CO₂ reduction to CO. Some water-soluble catalysts were found to serve as outstanding catalysts showing high selectivity to CO₂ reduction versus water reduction even under fully aqueous media. We futher confirmed that the formate forms via the nucleophilic attack of a metal-hydride at the carbon center of CO₂ rather than the classically accepted pathway via the insertion of CO₂ into a metal-hydride bond. The CO₂ reduction to formate were shown to undergo via the M-H attack with the lack of any O(formate)-coordinated products and directly ends up with the release of formate, demonstrating the outstanding efficiencies of these catalysts in the CO₂-to-HCOOH conversion. Water-soluble Rh(Cp*)(bpy)Cl derivatives were also shown to shown a unique water-induced high selectivity in CO₂-to-HCOOH conversion.

» Ken's Website

Professor, University of Padua, Italy

» Marcella's Website

Water Oxidation Catalysis for Solar Energy Applications

Department of Chemistry, Department of Molecular Biophysics & Biochemistry, and Yale Energy Sciences Institute, Yale University, New Haven, CT USA

Devising cost-effective methods for efficiently capturing and storing solar energy is among the grand challenges of science. We are using insights from studies of natural photosynthetic systems to develop bioinspired materials for photo-electrochemical water oxidation and solar fuel production by using molecular catalysts and dyes attached to mesoporous metal oxide photoanodes. Molecular catalysts are known for their high activity and tunability, but their solubility and limited stability often restrict their use in practical applications. We are developing anchoring chemistry to attach molecular water oxidation catalysts to metal oxide surfaces, which not only greatly increases the stability of the molecular catalyst but also improves the catalytic performance of the oxide material. Our progress on the development and characterization of molecular water and ammonia oxidation catalysts and their use in materials for artificial photosynthesis will be discussed.

» Gary's Website

Professor, Westlake University, China

» Licheng's Website

The next generation of solar energy conversion schemes calls for a unifying vision, dissecting a multi-level chemical complexity by: (i) optimization of each “a-solo” components (photoadsorbers, multi-redox catalysts, electron/proton relays, semiconductors, conductive scaffolds); (ii) their sophisticated assemblies (photo-induced charge separation and transport, oxidative/reductive catalysis, photoprotection) and (iii) the orchestration of a mechanistic cascade for efficient solar-to-fuel energy storage. This symposium focuses on the organic-inorganic interfaces at the frontier of molecular and materials science enabling the “green shift” of Artificial Photosynthesis. Scientific sessions involve world recognized experts and emerging investigators covering the fields of photo-(electro)catalysis applied to water splitting and CO₂ reduction, supramolecular sciences, and photo-biology, key technologies and advanced characterization methods (nanosciences, electrochemistry, photochemistry, advanced spectroscopy and computational modelling).