www.afm-journal.de © 2020 Wiley-VCH GmbH 2009083 (1 of 10) FULL PAPER Vanadium Dopants: A Boon or a Bane for Molybdenum Dichalcogenides-Based Electrocatalysis Applications Hui Ling Chia, Carmen C. Mayorga-Martinez, Zdeněk Sofer, Petr Lazar, Richard D. Webster, and Martin Pumera* The ever-rising concerns with regards to energy shortages and climate change have made the search for clean and renewable energy sources a pressing priority for the sustainable development of societies. Although, conventional precious metal-based catalysts such as platinum, iridium, and ruthenium are able to efciently catalyze the conversion of chemical to electrical energy, they are often very costly, scarce, and sufer from poor stability, hence impeding their widespread applications. The limitations of the current state-of art catalysts have propelled tremendous eforts in search for alternative catalysts. Notably, transition metal dichalcoge- nides (TMDs) have spurred much enthusiasm because of their natural abundance, low cost, and remarkable catalytic activity. Numerous studies have recounted that doping can tune the properties of TMDs and that vanadium dopants reportedly improve the electrical properties of Group 6 TMDs. Herein, the authors aspire to investigate the efects of doping varying amounts of vanadium on molybdenum dichalcogenides on their electrocatalytic activities toward hydrogen evolution reaction, oxygen evolution reaction, and oxygen reduction reaction. Despite previous studies bespeaking promising efects, the results here demonstrate both improvements and worsening of electrocatalytic performances from varying the stoichiometry of vanadium dopants in molybdenum dichalco- genides, depending on the type of materials and intended electrochemical applications. DOI: 10.1002/adfm.202009083 1. Introduction The ever-rising concerns with regards to energy shortages and climate change have made the search for clean and renewable energy sources a pressing priority for the sustainable development of societies as well as alleviating the environmental hazards posed by fossil fuels. As such, noteworthy amount of research vigor has been dedicated to exploring alternative sources of energy including solar, geo- thermal, and wind energies. [1–3] In order to fully maximize the utility of such inter- mittent renewable energy sources, it is of great importance to develop advanced energy storage and conversion technolo- gies such as electrocatalytic processes, supercapacitors, and metal–air batteries. These technologies often rely heavily on electrochemistry principles which aid in converting chemical energy into electrical energy. [4–6] Even though conventional pre- cious metal-based catalysts such as plat- inum (Pt), iridium (Ir), and ruthenium (Ru) are able to catalyze these conver- sions efciently, they are often very costly, scarce, and sufer from poor stability, H. L. Chia NTU Institute for Health Technologies Interdisciplinary Graduate School Nanyang Technological University 50 Nanyang Drive, Singapore 637553, Singapore H. L. Chia, Prof. R. D. Webster Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link, Singapore 637371, Singapore H. L. Chia, Dr. C. C. Mayorga-Martinez, Prof. M. Pumera Center for Advanced Functional Nanorobots Department of Inorganic Chemistry Faculty of Chemical Technology University of Chemistry and Technology Prague Technická 5, Prague 6, Czech Republic E-mail: pumeram@vscht.cz Prof. Z. Sofer Department of Inorganic Chemistry University of Chemistry and Technology Prague Technická 5, Prague 6, Czech Republic Dr. P. Lazar Regional Centre of Advanced Technologies and Materials Faculty of Science Palacky University Olomouc Šlechtitelů 27, Holice, Olomouc 783 71, Czech Republic Prof. M. Pumera Department of Medical Research China Medical University Hospital China Medical University No. 91 Hsueh-Shih Road, Taichung 40402, Taiwan Prof. M. Pumera Department of Chemical and Biomolecular Engineering Yonsei University 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea The ORCID identifcation number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.202009083. Adv. Funct. Mater. 2020, 2009083