Effect of sodium dodecyl sulfate surfactant concentrations on the novel strontium copper oxide nanostructures for enriching hydrogen evolution reaction electrochemical activity in alkaline solution

Abstract

Nowadays, hydrogen evolution reaction (HER) has gained more attention than the oxygen evolution reaction (OER) in water-splitting. The OER, which involves a four-electron process, is more complex whereas the HER, which involves a two-electron process, is more easy. Hydrogen is one of the promising and efficient energy carriers for renewable and sustainable energy yield. In this work, we have successfully prepared a low-cost electrocatalyst of strontium copper oxide (SCO) through a simple co-precipitation method, followed by an annealing process. The X-ray diffraction is consistent with an orthorhombic structure of SCO. The different modes of vibrations containing Cu, Sr, and O bonds were identified by using the Raman and Fourier transform infrared spectra. The scanning electron microscopy images confirmed that the introduction of sodium dodecyl sulfate (SDS) surfactant allowed to control the size and morphology of the prepared material. Electrochemical measurements indicated that 2 wt% SDS-assisted SCO material exhibited excellent HER performance and high stability. It achieved 166 mV to deliver 10 mA/cm2 and attained the low 124 mV/dec Tafel slope value, indicating that hydrogen evolution reaction followed the Volmer–Heyrovsky mechanism. Compared to the pure and 1 wt% SDS-SCO, 2 wt% SDS-SCO material exhibited a high electrochemically active surface area (ECSA) of 19.3 cm2 and showed a low 0.33 Ω charge-transfer resistance, indicating the presence of supplementary active sites and enhanced electrical conductivity than the reference electrocatalysts. Hence, this work could be considered as a successful approach in exploring the performance of alkaline-based metal oxides in electrochemical hydrogen evolution reactions.