Issue 14/2021 - Novel carbon nanocatalysts efficiently catalyze the conversion of hydrogen sulfide

Recently, researchers from the Dalian Institute of Chemical Physics, Chinese Academy of Sciences designed and prepared an integrally formed carbon nanocomposite catalytic material, which can be used for efficient catalytic conversion of high content of hydrogen
sulfide in industrial gas under continuous working conditions.
This study provides a new idea
for the design of highly active desulfurization nanocarbon catalysts with complex reaction environments.

It is understood that the material is suitable for hydrogen sulfide selective oxidation process under complex working conditions such as high oxygen content, high carbon dioxide content and high water vapor content, and has excellent selectivity and reaction stability
of high value-added sulfur products.

At present, the widely used hydrogen sulfide selective oxidation catalyst has problems such as inresistance to water vapor and impurity gas, resulting in poor activity and stability of the catalyst, which is more prominent
in the continuous reaction process.
Therefore, it is of great application value
to design a catalyst for selective oxidation of continuous hydrogen sulfide with high catalytic activity, high sulfur selectivity and excellent anti-impurity gas characteristics under complex conditions.

Because of its unique surface chemistry and excellent catalytic properties, nanocarbon materials have been widely studied in selective oxidation of hydrogen sulfide, but due to the overactive active center and strong exothermic characteristics of the reaction, the product is easily overoxidized to SO_x
.
On the basis of the preliminary work, the research team modified the phosphate surface of the nitrogen-doped monolithic carbon material, and improved the selectivity
of the product on the basis of ensuring that the original conversion rate was greater than 97%.

In addition, the catalyst can still maintain its excellent catalytic activity and stability
in the reaction atmosphere containing impurity gas.
Combining characterization methods, kinetic analysis and theoretical calculations, the researchers found that there is an interaction between the introduced phosphorus group and the pyridine nitrogen site as the active center of the reactivity, which can inhibit the adsorption and activity of oxygen molecules at the active site, thereby avoiding the occurrence of excessive oxidation, and improving product selectivity and improving product selectivity
.