Synthesis of MoO.sub.2 on steel substrate for hydrogen evolution reaction in water splitting: a new approach

• Published in: Journal of materials science Vol. 58; no. 3; pp. 1403 - 1414
• Main Authors: Sapakal, Suchitra N, Khan, Ayesha, Khobragade, J. M, Kadam, Anamika V
• Format: Journal Article
• Language: English
• Published: Springer 01.01.2023
• Subjects: Electric properties; Hydrogen; Molybdenum oxides; Water
• ISSN: 0022-2461
• DOI: 10.1007/s10853-022-08079-7

Metallic molybdenum dioxide (MoO.sub.2) films were grown on stainless steel (SS) substrate by a simple hydrothermal process employing citric acid at different deposition times that acts as a chelating agent. The tuning of the bandgap of SS and MoO.sub.2 favours the water splitting which could not be obtained on other conventional substrates. Initially, the morphology of MoO.sub.2 was aggregated ultrathin nanosheets for a six-hour reaction time, and it changed to other diverse morphology by varying the reaction time. XRD data confirm the formation of MoO.sub.2 nanoparticles. The electrochemical water activation studies show that 10-h (M10) MoO.sub.2 film on SS is showing an excellent hydrogen evolution reaction (HER) catalyst with good stability (9 h). MoO.sub.2 on SS displays a low onset overpotential of - 33 mV vs RHE with a Tafel slope of 39 mV/dec and - 138 mV vs RHE overpotential at 10 mA/cm.sup.2 current density. The large active surface area and lesser electrochemical charge-transfer resistance offered by the MoO.sub.2 nanostructures play a major role in the enhanced HER activity.