A recent research paper from DTU Energy showing that electrospun catalytic membranes can remove nitrous oxides (NOx) from, e.g., diesel exhausts with high efficiency, has been named a top 10% paper by the journal Environmental Science: Nano.
Porous membranes are used in many different contexts, from water treatment and air purification to catalysis. Free-standing membranes are usually made of polymers to make them both flexible and mechanically stable. But the use of polymers can be a problem if the membrane is to operate in chemically aggressive environments or at elevated temperatures, where most polymers rapidly degrade. Instead, ceramics can be used if they can be shaped appropriately. The challenge is to produce a membrane with high porosity and excellent mechanical properties.
Now, an international team led by researchers from DTU Energy has demonstrated that electrospinning makes the difference in designing more efficient catalytically active ceramic membranes. Electrospinning uses an electrical field to draw out thin threads of material from a solution. By co-electrospinning ceramic precursors and a polymer and afterwards heating the fibers to above 500 °C, the polymer is burned off and one is left with a highly porous robust membrane consisting of nanofibers of ceramic catalyst material. The research team demonstrated the catalytic activity of the membrane towards NOx removal and showed that it was significantly higher than state-of-the-art nanoparticles and nanofibers. They also demonstrated long-term stability of the membrane. This makes their work promising for use in actual devices.
"We hope that our good results will lead to improved gas cleaning devices for the future"
Professor Vincenzo Esposito
The paper ‘Highly porous Ce-W-TiO2 free-standing catalytic membranes for efficient de-NOx via ammonia selective catalytic reduction’ appeared recently in Environmental Science: Nano, a journal published by the Royal Society of Chemistry and focusing on the environmental impact of nanotechnology and its sustainable use. Due to the extremely positive reports made by the anonymous referees during the review process as well as the editors’ assessment of the importance and impact of the work, the paper was named a ‘HOT article’ and among the top 10% papers published by the journal.
Professor Vincenzo Esposito states in that connection: “The team is glad that our work has been recognized as an important contribution to membrane science. But, of course, we are even happier about the good results themselves, and we hope that they will lead to improved gas cleaning devices for the future”.