Gustavo Moreira Delfino¹, Rashid Mehmood¹, Tamires de Souza Nossa², Jeferson Aparecido Moreto¹, Marcos Roberto de Vasconcelos Lanza¹, Haroldo Cavalcanti Pinto^1
1University of São Paulo, São Carlos, SP, Brazil
²Federal Institute of São Paulo, Itapetininga, SP, Brazil
Water splitting electrolysis is a promising pathway to meet the global demand for clean and renewable energy. Electrocatalysts play a critical role in water splitting technologies and thus represent a key component to achieve highly efficient hydrogen production. However, platinum group metals (PMG) are commonly used as catalysts in these technologies, which implies high costs and makes large-scale commercialization difficult. Transition metal-based catalysts are an appealing option to replace PGM catalysts because of their low-cost, high efficiency and long stability. Nickel nanoparticles (Ni-NPs) have demonstrated excellent catalytic activity for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), which makes them a viable bifunctional catalyst for water splitting systems. In this work, Ni-NPs for HER were embedded in graphitic carbon nitride (gCN) supports by using two distinct manufacturing routes: chemical synthesis and magnetron sputtering. The morphology and structure of chemically produced and sputtered electrodes were evaluated using scanning electron microscope (SEM) transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Electrode systems and cyclic voltammetry (CV) were employed to understand the electrochemical activity of the HER. The results reveal the catalytic activity of Ni-NP embedded in gCN and the reaction rate for HER compared to pristine gCN by controlling the particle size, enlarging the active sites, and boosting charge transfer properties, and compare the catalytic efficiency for the two manufacturing routes. This contribution provides a cheaper and stable HER electrocatalyst that can be used in water splitting systems for efficient hydrogen generation.