A New Nanoreactor Mimics Living Cells to Turn Sunlight Into Hydrogen Peroxide

A new hollow nanoreactor inspired by the way living cells organize chemical reactions could provide a cleaner and more efficient route for producing hydrogen peroxide using visible light. The innovative material combines a light-trapping inner cavity with a proton-shuttling outer shell, allowing chemical reactions to occur in a highly controlled nanoscale environment.

The research was published in the Journal of the American Chemical Society. It was led by Prof. Li Can at the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. Jian Liu's team at Inner Mongolia University.

The researchers developed a hollow CdS@polydopamine nanoreactor that imitates two important characteristics of living cells: controlled compartmentalization and efficient movement of chemical species. Their work demonstrates how principles found in biology can be incorporated into artificial nanomaterials for applications in clean chemistry and artificial photosynthesis.

Learning From the Chemistry of Living Cells

Living cells are remarkably efficient chemical factories. Inside a cell, thousands of chemical reactions can happen simultaneously without becoming chaotic. This is possible because cells carefully organize their molecules and reactions within small, specialized compartments.

These compartments control where molecules go, how they interact and how quickly reactions take place. Cells also use biological molecules to transfer protons and electrons between different parts of their chemical systems.

Scientists are trying to reproduce some of these abilities using artificial materials. This emerging approach, often described as nanocell engineering, combines concepts from biology, chemistry and nanotechnology.

The goal is not to create an artificial cell in the traditional sense. Instead, researchers are designing tiny structures that can reproduce selected functions of cells, such as molecular transport, energy conversion and controlled chemical reactions.

The new CdS@polydopamine nanoreactor is an example of this strategy.

Two Cell-Inspired Features

The nanoreactor contains two key design features that work together.

The first is a dynamic catechol/o-benzoquinone redox pair within its polydopamine shell. This chemical system does not function as a traditional biological proton pump. Instead, it acts as a proton relay.

During chemical reactions, protons need to move between different reaction sites. The catechol/o-benzoquinone pair can repeatedly accept and release protons, helping transport them through the system.

This process accelerates proton-coupled electron transfer (PCET). PCET is important in many chemical and biological reactions because the movement of protons and electrons can influence each other.

By improving this proton transfer, the artificial nanoreactor can make the overall light-driven chemical process more efficient.

The second major feature is the nanoreactor's compartmentalized hollow structure.

At its center is a nanoscale cavity surrounded by a porous shell. This creates a confined environment where molecules can gather and interact before moving through the reaction system.

The cavity also helps capture incoming light. In other words, the structure does more than simply provide space for chemical reactions—it helps manage both molecules and photons at the nanoscale.

Turning Visible Light Into Hydrogen Peroxide

Hydrogen peroxide (H₂O₂) is an important chemical used in areas ranging from disinfection and environmental treatment to chemical manufacturing.

Conventional production of hydrogen peroxide can require significant energy and industrial infrastructure. Researchers are therefore exploring alternative approaches that can produce H₂O₂ more sustainably.

One promising possibility is artificial photosynthesis, in which sunlight or visible light provides the energy needed to drive chemical reactions.

In the new system, hydrogen peroxide is produced through two important half-reactions: oxygen reduction and water oxidation. For the overall process to work efficiently, the rates of these reactions need to remain properly balanced.

The cell-inspired nanoreactor helps coordinate these processes.

Under visible-light illumination in an aqueous solution, the material achieved a hydrogen peroxide production rate of 3.24 mmol per gram of catalyst per hour. It also reached a solar-to-chemical conversion efficiency of 1.2%.

These results demonstrate that carefully controlling the nanoscale environment can improve the performance of photocatalytic chemical production.

How Does the Nanoreactor Work?

The system relies on a photocatalytic mechanism involving a Z-scheme heterojunction.

When visible light reaches the material, the semiconductor components absorb the light and generate energetic charge carriers. These charges participate in chemical reactions involving oxygen and water.

However, simply generating electrons and holes is not enough. They must reach the correct reaction sites and participate in proton and electron transfer efficiently.

This is where the polydopamine shell and hollow cavity become important.

The porous shell helps molecules move through the structure, while the proton-relay system assists proton transfer. At the same time, the hollow cavity provides a confined environment that can enhance molecular interactions and trap light.

Together, these features help overcome one of the major challenges in photocatalysis: coordinating multiple processes that occur at different speeds.

Researchers Used Multiple Techniques to Understand the Process

To determine why the nanoreactor performs efficiently, the researchers used several complementary techniques.

These included in situ spectroscopy, photochemical analysis, finite element simulations and theoretical calculations.

These methods allowed the team to examine the behavior of the nanoreactor while the chemical reactions were taking place. The researchers could then connect the observed chemical behavior with the structure of the material.

The results provided evidence for the proposed cell-inspired mechanism and helped explain how the Z-scheme heterojunction contributes to photocatalytic hydrogen peroxide production.

A Recyclable Catalyst for Sunlight-Driven Chemistry

The researchers also took an important step toward making the material easier to use in practical applications.

They embedded the nanoreactors inside an environmentally friendly sodium alginate hydrogel matrix. The resulting material forms a solid and recyclable photocatalyst.

This design allows the catalyst to be recovered and reused instead of remaining dispersed in a liquid reaction mixture.

Importantly, the hydrogel-based photocatalyst was able to continuously produce hydrogen peroxide under natural sunlight while maintaining stable performance.

This feature could be particularly valuable for future applications because sunlight is an abundant renewable energy source, while a recyclable solid catalyst can simplify separation and reuse.

A Step Toward Artificial Chemical Systems Inspired by Life

The importance of this research extends beyond hydrogen peroxide production.

Living cells have evolved highly sophisticated ways to organize chemical reactions. By reproducing selected features of this organization in synthetic materials, scientists may be able to build artificial chemical systems that are more efficient, selective and sustainable.

The new nanoreactor demonstrates how spatial organization, proton transport and light management can be combined within a single nanoscale structure.

Such strategies could eventually find applications in artificial photosynthesis, renewable energy conversion, environmental chemistry and sustainable chemical manufacturing.

Prof. Li Can described the work as a new strategy for designing biomimetic nanoreactors that increasingly reproduce the sophisticated functions of living cells. According to the researchers, this approach could open new opportunities in artificial photosynthesis, energy catalysis and synthetic chemistry.

The Bigger Picture

The new CdS@polydopamine nanoreactor represents an interesting shift in how scientists approach photocatalysis. Instead of focusing only on developing a more active catalyst, the researchers designed a miniature chemical environment that helps different parts of the reaction work together.

Its hollow cavity can manage light and molecular confinement, while the polydopamine shell helps shuttle protons and support efficient chemical transformations.

Although further research will be needed before such systems can be deployed on a large industrial scale, the concept offers an important lesson: the architecture surrounding a catalyst can be just as important as the catalyst itself.

By borrowing design principles from living cells, scientists are moving closer to creating artificial systems capable of carrying out complex chemical processes using renewable energy. The result could be a new generation of nanoreactors that transform sunlight, water and simple molecules into valuable chemicals with less environmental impact.

Reference:

1. Haitao Li, Mengyuan Ji, Jinlu He, Dehui Deng, Jincai Zhao, Jian Liu, Can Li. Biomimetic Redox-Mediated Proton Relay in Nanoreactors for Photocatalysis. Journal of the American Chemical Society, 2026; DOI: 10.1021/jacs.6c08170