Herein, the effects of different types of surfactants including sodium dodecyl sulfate (SDS), cetyltrimethyl ammonium bromide (CTAB), and t-octyl phenoxy polyethoxy ethanol (Triton X-100, TX-100) were presented on the hydrogen evolution reaction (HER) at the surface of carbon paste electrode (CPE) modified with Pd@Cu nanoparticles. Firstly, Cu nanoparticles with average diameters at about 80 nm were electro-deposited at the CPE surface in H2SO4 solution containing CTAB and CuSO4 by potentiostatic method. Then, Pd@Cu bimetallic nanoparticles with diameters at about 75 nm were prepared through galvanic replacement reaction between PdII ions and Cu particles. The synthesized Cu nanoparticles were covered by CTAB in solution and surface tension of the nanoparticles were decreased, and consequently stabilized. Also, the surfactants play different roles on the HER depending on the electrode polarity and surface charges. The electrocatalytic activity of the Pd@Cu/CPE and nano-Cu/CPE towards HER was found to be highest in the presence of SDS. The effects of galvanic replacement reaction and type of surfactants on kinetic parameters of the HER such as cathodic electron transfer coefficient and exchange current density were comparatively investigated.
