Toward the development of inexpensive photocatalysts that can effectively utilize sunlight
- Date: Aug 27, 2025
- Time: 03:00 PM - 04:00 PM (Local Time Germany)
- Speaker: Kosei Ito
- Keio University, Tokyo, Japan
- Location: Max Planck Institute for Solid State Research
- Room: 4D2
Photocatalysts are promising materials that can drive chemical reactions using only sunlight as an energy source. In particular, photocatalytic hydrogen production has attracted considerable attention, and recent studies indicate that this technology is approaching practical viability1. In addition to hydrogen generation, photocatalysts hold potential in diverse fields such as fuel synthesis from CO₂2 and environmental remediation, including viral decomposition3.
Despite this promise, the performance of current photocatalyst systems appears to have reached a plateau, pointing out the need for innovative approaches4. One major challenge is the effective utilization of visible light, which constitutes the majority of the solar spectrum. However, due to intrinsic limitations of existing photocatalytic mechanisms, this remains difficult to achieve. Moreover, the latest high-performance photocatalysts often require large amounts of rare metals, leading to high material costs and reduced cost-efficiency, thereby hindering practical implementation.
To overcome these limitations, our research focuses on two primary strategies: (1) the development of inexpensive metal-free photocatalysts (Fig.1),5,6 and (2) the effective utilization of visible light and reducing dependence on rare metals through composite photocatalysts combining two types of photocatalysts (Fig.2)7.
Furthermore, we are expanding our investigations into novel applications, including the decomposition of microplastics in marine environments and the conversion of waste plastics into usable fuels via photocatalytic processes.
In this presentation, I will first provide an overview of the fundamental principles of photocatalysis, followed by talk on current research trends and the remaining challenges. After that I will introduce our recent research efforts described above.
1, H. Nishiyama et.al, Nature, 598, (2021)
2, S. Shoji et.al, Nat. Catal., 3, 148-153, (2020)
3, Y. Lu et.al, Sci. Rep., 12, 16038, (2022)
4, T. Takata et.al, Nature, 581, (2020)
5, K. Ito et al., ACS Mater. Au, 5, 299−307, (2025)
6, K. Ito et al., J. Photochem. Photobiol. A, 443, 114824, (2023)
7, K. Ito et al., Phys. Chem. Chem. Phys., 26, 153-160 (2024).
Despite this promise, the performance of current photocatalyst systems appears to have reached a plateau, pointing out the need for innovative approaches4. One major challenge is the effective utilization of visible light, which constitutes the majority of the solar spectrum. However, due to intrinsic limitations of existing photocatalytic mechanisms, this remains difficult to achieve. Moreover, the latest high-performance photocatalysts often require large amounts of rare metals, leading to high material costs and reduced cost-efficiency, thereby hindering practical implementation.
To overcome these limitations, our research focuses on two primary strategies: (1) the development of inexpensive metal-free photocatalysts (Fig.1),5,6 and (2) the effective utilization of visible light and reducing dependence on rare metals through composite photocatalysts combining two types of photocatalysts (Fig.2)7.
Furthermore, we are expanding our investigations into novel applications, including the decomposition of microplastics in marine environments and the conversion of waste plastics into usable fuels via photocatalytic processes.
In this presentation, I will first provide an overview of the fundamental principles of photocatalysis, followed by talk on current research trends and the remaining challenges. After that I will introduce our recent research efforts described above.
1, H. Nishiyama et.al, Nature, 598, (2021)
2, S. Shoji et.al, Nat. Catal., 3, 148-153, (2020)
3, Y. Lu et.al, Sci. Rep., 12, 16038, (2022)
4, T. Takata et.al, Nature, 581, (2020)
5, K. Ito et al., ACS Mater. Au, 5, 299−307, (2025)
6, K. Ito et al., J. Photochem. Photobiol. A, 443, 114824, (2023)
7, K. Ito et al., Phys. Chem. Chem. Phys., 26, 153-160 (2024).