researchers at the national institute of materials science (tsukuba, japan), waseda university in tokyo, and university wollongong in new south wales, australia collaborated on a project to synthesize highly porous rhodium nanoparticles to provide more efficient catalytic converters, according to a report by the australian nuclear science and technology organization (antso), which was also part of the international project.

researchers have created a new nanoparticle for more efficient catalytic converters.
(antso)

the nanoparticles were produced using a soft template and simple solution chemistry and demonstrated stability up to 400°c and were three or four times more efficient than current catalytic converters, which are used to convert toxic gases into less toxic pollutants.

the article explained, “the research has the potential to significantly reduce the amount of pollution caused by cars and trucks.”

it continued, “small angle neutron scattering (sans) was performed on the quokka instrument at the australian centre for neutron scattering by dr. katy wood and dr. md shahriar hossain, senior research fellow from the university of wollongong, to characterise the micelles in solution at two stages of the five-step process.”

rhodium is less reactive than other materials under mild conditions, but researchers overcame this stability by using a polymer, poly(ethylene oxide)-b-poly(methylmethacrylate (peo-b-pmma), which self-assembled into spherical micelles in water. when na3rhcl6 was added, the micelles formed composites and, after undergoing nucleation, “they coalesced and grew into mesoporous rhodium nanostructures that could be extracted using a solvent.”

studies showed that the micelles were 20 nanometers and were homogenous in their spherical shape, which indicates that this process could be modified to change pore size in the final product.

the article added, “ultraviolet-vis absorption spectroscopy suggested the dissolved metal ions coordinate to the micelle surface and drove the nucleation of the rhodium precursor.”

the research was recently published in nature communications. the abstract read:

“mesoporous noble metals are an emerging class of cutting-edge nanostructured catalysts due to their abundant exposed active sites and highly accessible surfaces. although various noble metal (e.g. pt, pd and au) structures have been synthesized by hard- and soft-templating methods, mesoporous rhodium (rh) nanoparticles have never been generated via chemical reduction, in part due to the relatively high surface energy of rhodium (rh) metal.

“here we describe a simple, scalable route to generate mesoporous rh by chemical reduction on polymeric micelle templates [poly(ethylene oxide)-b-poly(methyl methacrylate) (peo-b-pmma)]. the mesoporous rh nanoparticles exhibited a ∼2.6 times enhancement for the electrocatalytic oxidation of methanol compared to commercially available rh catalyst.

“surprisingly, the high surface area mesoporous structure of the rh catalyst was thermally stable up to 400 °c. the combination of high surface area and thermal stability also enables superior catalytic activity for the remediation of nitric oxide (no) in lean-burn exhaust containing high concentrations of o₂.”