Reaction time influence on copper tin sulfide micro flowers for enhanced electrochemical hydrogen evolution reaction (HER) performance

Abstract

Herein, we report the effective way to optimize the copper tin sulfide (Cu2SnS3) micro flowers via a simple hydrothermal method using different reaction times, which could enhance the fabricated electrocatalyst in electrochemical water splitting applications. The prepared Cu2SnS3 was identified by X-ray diffraction (XRD) analysis, which demonstrated the formation of triclinic phase Cu2SnS3 with a=0.664, b=1.151 and c=1.993 nm, respectively. Phase confirmation was further analyzed by using Raman and Fourier-transform infrared (FTIR) spectroscopy, which also demonstrated pure tetragonal copper tin sulfide (CTS) phase. The morphology of the copper tin sulfide (CTS) materials was explored with the help of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies, which confirmed crystalline nature of triclinic copper tin sulfide (CTS) 3D hierarchical micro flowers. The prepared electrocatalyst was further characterized employing Energy-dispersive (EDX) and X-ray (XPS) spectroscopy. It exhibited chemical composition of Cu2p, Sn3d, and S2p in stoichiometric ratio with an atomic percentage of Cu, Sn, and S being 37.5, 40.7, and 21.7%, respectively. CTS-16 h exhibited 151 mV to afford 10 mA/cm2 and 139 mV/dec Tafel slope value, which was demonstrated by electrochemical characterizations. Moreover, the efficient electrocatalyst of CTS-16 h exhibited 131.5 cm2 electrochemical active surface area, while the other catalysts such as CTS-4 h, CTS-8 h and CTS-24 h were 49.25, 67.5, and 107.5 cm2 respectively. The CTS-16 h electrode shows excellent stability towards long-term CA test for one day with 94% retention. Therefore, the overall result suggests that the synthesized material provided a new approach for the noble metal catalysts substitute, and it is a potential material for clean energy systems.