Open AccessTwo Birds with One Stone: Concurrent Ligand Removal and Carbon Encapsulation Decipher Thickness-Dependent Catalytic Activity
Author(s) -
Kun Guo,
Litao Chang,
Ning Li,
Lipiao Bao,
Samir de Moraes Shubeita,
Aliaksandr Baidak,
Zhixin Yu,
Xing Lu
Publication year - 2022
Publication title -
nano letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.853
H-Index - 488
eISSN - 1530-6992
pISSN - 1530-6984
DOI - 10.1021/acs.nanolett.2c03181
Subject(s) - calcination , catalysis , x ray photoelectron spectroscopy , carbon fibers , chemistry , oleylamine , chemical engineering , materials science , chemical physics , nanotechnology , nanoparticle , composite material , organic chemistry , composite number , engineering
A carbon shell encapsulating a transition metal-based core has emerged as an intriguing type of catalyst structure, but the effect of the shell thickness on the catalytic properties of the buried components is not well known. Here, we present a proof-of-concept study to reveal the thickness effect by carbonizing the isotropic and homogeneous oleylamine (OAm) ligands that cover colloidal MoS 2 . A thermal treatment turns OAm into a uniform carbon shell, while the size of MoS 2 monolayers remains identical. When evaluated toward an acidic hydrogen evolution reaction, the calcined MoS 2 catalysts deliver a volcano-type activity trend that depends on the calcination temperature. Rutherford backscattering spectrometry and depth-profiling X-ray photoelectron spectroscopy consistently provide an accurate quantification of the carbon shell thickness. The same variation pattern of catalytic activity and carbon shell thickness, aided by kinetic studies, is then persuasively justified by the respective limitations of electron and proton conductivities on the two branches of the volcano curve.