Design of multifunctional framework materials for sustainable photocatalysis

The goal of sustainable chemistry has led chemists to use renewable energy for chemical reactions, minimize hazardous waste, and maximize the economics of atoms. Nature provides the blueprint for photosynthesis, in which carbohydrates are produced from carbon dioxide and water under the irradiation of sunlight.

However, this process relies on a complex system involving multiple enzymes and light-harvesting antennas, making it inherently less efficient at converting solar energy. Artificial photosynthetic systems are a long-standing scientific pursuit and offer potential solutions to sustainable chemistry.

A team at the University of Chicago led by Professor Wenbing Lin is working to develop an artificial photocatalytic system using framework materials, a type of porous material formed by periodic combinations of metals and organic components.

By characterizing these materials using cutting-edge techniques, researchers have gained a deep understanding of how such artificial systems function at the molecular level. This knowledge has made it possible to fine-tune materials for different light-driven reactions.

In a mini-review published in Carbon Future on September 13, 2024, researchers summarized recent achievements in artificial photosynthesis and photocatalysis, highlighting important advances and future opportunities.

“Nature performs precise chemistry within living organisms to create complex molecules, often at the expense of efficiency,” said Professor Wenbing Lin.

“We need to go beyond nature to address the challenges we face today. And fortunately, by precisely controlling the structure and composition of framework materials, we can significantly We have developed an artificial system that surpasses that of

This review shows how chemical modification of framework materials can fine-tune their performance in reactions like photosynthesis.

To achieve these goals, the team identified critical components and validated their roles. Photosensitizers like chlorophyll absorb light energy. Like enzymes, catalysts use this energy to drive chemical reactions. These photosensitizers and catalysts have carefully tuned energy and electron transfer kinetics and are incorporated into the framework material.

“Incorporating the appropriate photosensitizer and catalyst into a framework material can improve its performance by more than an order of magnitude over simply mixing the photosensitizer and catalyst in solution,” says Lin. he explained.

The research team demonstrated significant improvements in more than a dozen photocatalytic reactions using these materials. This enhancement stems from the “pre-organization” effect also observed in natural systems, where photosensitizers and catalysts are placed in specific locations to facilitate chemical reactions.

Scaffold material can be easily recovered from the reaction mixture by centrifugation or filtration. The recovered material is used in the next reaction without compromising the catalytic activity. In one example, the framework material was used in eight cycles of one-pot synthesis of a cardiotonic agent without reducing catalyst performance.

“We believe this breakthrough has great potential for the sustainable synthesis of pharmaceuticals and other value-added products, and these research efforts will contribute to a more sustainable future. “Yes,” Lin said.

“The principles learned here can be applied to many other systems.” The research team hopes their review will inspire other researchers to rationally design other catalytic materials at the molecular level. I’m looking forward to it.

The first author was Yingjie Fan (Ph.D. ’24, currently a postdoctoral fellow at the University of California, Berkeley).