Bimetallic transition metal chalcogenide nanowire array: An effective catalyst for overall water splitting

Highlights: • First time, CoTe₂@CdTe nanowire array was synthesized as bifunctional electrocatalyst. • Nanowire array was used for overall water splitting and exhibited low onset potential. • Small Tafel slope value was observed for OER (68 mV/dec) and HER (90/dec). • High current density was observed at small potential with long-term stability. -- Abstract: The development of highly active, durable, and inexpensive bifunctional catalysts towards both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is one of the most challenging tasks in the term of renewable energy. Keeping in mind the current scenario, herein, we have synthesized bimetallic transition metal chalcogenides (CoTe₂@CdTe and CoSe₂@CdSe) by a very easy, single step hydrothermal process. During the synthesis, two different morphologies (i.e. spherical and wire) were obtained depending on the selection of chalcogen. It was found that Te based nanocomposite i.e. CoTe₂@CdTe showed a symmetrical nanowire array morphology with a high electrocatalytic surface area and good electrocatalytic activity towards both HER and OER. The structural, morphological and electrochemical features of synthesized nanocomposites were characterized by various useful techniques (like field emission scanning electron microscopy, high resolution transmission electron microscopy, powder X-ray diffraction analysis etc.) to confirm their successful synthesis. The CoTe₂@CdTe nanowire array has shown a small onset potential value, high current density, low Tafel slope value along with high stability towards overall water splitting.