Fuzhou University in China scientists report the synthesis of a macroscopic aerogel from carbonitride nanomaterials which is an excellent catalyst for the water-splitting reaction under visible-light irradiation. The study adds new opportunities to the material properties of melamine-derived carbonitrides.

The study has been published in the journal Angewandte Chemie.

Melamine can be polymerized with formaldehyde to give a highly durable and light resin, but it can also condensed to form nanostructures of carbonitride materials. These assemblies made of carbon and nitrogen combine the honeycomb-like electronically active network of graphene with some extra functionality of nitrogen. Searching for ways to assemble these nanostructures into a stable macroscopic architecture, Xinchen Wang and his team at Fuzhou University have now prepared a catalytically highly active and stable lightweight material, which serves well in artificial photosynthesis and offers very interesting structural and electronic properties.

Image Credit: Prof Wang, Fuzhou University. Click image for the largest view.

Aerogels are gels but without water – up to ninety-nine percent of their structure is air. This porosity gives them a huge surface ideal for catalytic or sensory application. As carbonitrides are materials with very interesting nanostructure and graphene-like properties but nitrogen functionality, it has long be sought to bring them into a controlled macroscopic assembly.

The authors said in the study, “Since CN is rich in nitrogen-containing groups, it is expected that CN may have interesting assembly behaviors like proteins or peptides in biological systems.”

The enhanced surface area and higher number of catalytic sites would make these aerogels highly functional macroscopic materials. Employing only physical interparticle forces intrinsic to the nanoparticles, the scientists prepared the aerogel by making a colloidal aqueous solution of carbonitride nanoparticles to settle first into a hydrogel, then converting it into a stable aerogel by a conventional freeze-drying technology.

The authors explained that, “This method has several advantages, including scalability for mass production and low cost.” In combination with a platinum co-catalyst, the aerogel was much better a photocatalyst for hydrogen evolution than the bulk carbonitride, and hydrogen peroxide was generated from pure water under visible-light irradiation when the bulk carbonitride failed.

By joining forces of chemical and physical characteristics from the nano- to the macroscale, they have created a new lightweight material with excellent catalytic prospects. This promising application of melamine building blocks points the way forward to new materials, and is far apart from the well-established mass production of the light and durable, but not so thermostable melamine plastic dishes.

It is interesting to see the Chinese making innovative contributions to the knowledge base. Over the past few years the site has seen more and more non U.S. study and research work make the peer review press. Its great to see them coming on and a disappointment for U.S. folks laboring under low funding – blown by politicians on choosing leader business projects.

The only questions here are just how is the co-catalyst platinum involved and can that be “low cost”?


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