Positive and Negative Effects of Dopants toward Electrocatalytic Activity of MoS2 and WS2: Experiments and Theory Veronika Urbanová, Petr Lazar, Nikolas Antonatos, Zdeněk Sofer, Michal Otyepka and Martin Pumera* ACS Appl. Mater. Interfaces 2020, 12(18), 20383-20392