Noble metals, like platinum (Pt), are known for their efficient catalyzingability in many reactions but its rare existence and high value restricted their application as catalysts. A big problem is their thermodynamic instability, resulting from the tendency of atomic aggregation under high temperature, which is a necessary condition to ensure the reactions.
The group of Prof. LIANG Haiwei, associated with Prof. WU Xiaojun and Prof. LU Junling from University of science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS), offered a solution. Their result was published on Nature Communications on May 25th.
Their strategy is to load noble metal nanoclusters, Pt in their experiment, into sulfur doped carbon matrix. Though seems a little untraditional, for sulfur is widely accepted as a poison reagent for catalysts, this method is of great efficiency in stabilizing nanoclusters under temperature up to 700 °C as shown in the reported experiment.
The strong chemical interaction between Pt and sulfur atoms from the sulfur-doped carbon support made the migration of Pt atom harder and stabilized the nanoparticles. The sulfur doped carbon matrix can form “talons” around the sulfur atoms owing to the sulfur-carbon interaction, so Pt nanoclusters can be grabbed tightly by this doped carbon material instead of merely adhering to the carrier. The aggregation and migration of metal atoms are reduced to an extent by this way and metal nanoclusters are stabilized.
Moreover, the newly introduced catalyst showed a greater selectivity and stability of propylene than sulfur-free catalyst in a propane dehydrogenation to propylene experiment.
Schematic diagram of sulfur stabilization strategy for inhibiting sintering of metal nanoclusters at high temperature (Image by YIN Peng et al.)
To have a more precise illustration of this theory, they conducted density functional theory (DFT) calculation to make quantitative aspect discussions to this effect. And the calculation result is closely matched to the experimental outcomes. Researchers also changed the noble metal to make sure that this theory is universally appliable, and it turned out to be a successful trial.
With the help of sulfur talons inside the carriers, noble metal nanoclusters can be stabilized to an extent, which suggesting the theoretical high-efficient low-cost catalysts is becoming feasible. Thus, we are more than hopeful in dealing with the energy shortage problem since all these brilliant scientists are working hard and making progress together.
Paper link:
https://doi.org/10.1038/s41467-021-23426-z
(Written by LIU Zige, edited by JIANG Pengcen, USTC News Center)
