General synthesis of noble metal (Au, Ag, Pd, Pt) nanocrystal modified MoS2 nanosheets and the enhanced catalytic activity of Pd–MoS2 for methanol oxidation

Abstract

A general and facile method for water-dispersed noble metal (Au, Ag, Pd, Pt) nanocrystal modified MoS₂ nanosheets (NM–MoS₂ NSs) has been developed. By using sodium carboxymethyl cellulose as a stabilizer, well-dispersed NM–MoS₂ NSs with homogeneously deposited noble metal nanocrystals (NM NCs) can be synthesized in aqueous solutions. Due to the transition from the semiconducting 2H phase to the metallic 1T phase, the chemically exfoliated MoS₂ (ce-MoS₂) NSs have improved electrochemical activity. The partially metallic nature of the ce-MoS₂ NSs and the catalytic activity of the NM NCs synergistically make NM–MoS₂ NSs a potential electrochemical catalyst. For the first time, Pd–MoS₂ NSs were used as an electrocatalyst for methanol oxidation in alkaline media. The results showed that Pd–MoS₂ NSs have enhanced catalytic activity with 2.8-fold anodic peak current mass density compared to a commercial Pd/C catalyst, suggesting potential for application in direct methanol fuel cells (DMFCs).