Applied Surface Science, Vol.492, 497-503, 2019
Surface modification of tungsten disulfide with polypyrrole for enhancement of the conductivity and its impact on hydrogen evolution reaction
A conducing polymer, polypyrrole, was deposited on tungsten disulfide flakes in situ during the oxidation of pyrrole. The conductivity of composites exceeded the conductivities of the parent components. This synergistic effect is explained by the deposition of more conducing ordered polypyrrole at first, and less conducing globular polypyrrole later after the whole available tungsten disulfide surface was coated. Such scenario was confirmed by electron microscopies. Raman and X-ray photoelectron spectroscopies proved the completeness of the coating. Despite the increase in the conductivity, the electrocatalysis of hydrogen evolution reaction on tungsten disulfide was reduced after polypyrrole deposition, confirming also effective coating of the substrate. A simple mixture of both components, however, improved the electrocatalytic effect compared with the composite or any of its components.
Keywords:Polypyrrole;Tungsten disulfide;Molybdenum disulfide;Chain ordering;Conducting composites;Hydrogen evolution reaction