Coprecipitation Synthesis of NiHCF/S-Doped g-C ₃ N ₄ for Bifunctional Electrochemical Studies

Metal hexacyanoferrates (MHCFs) are a kind of Prussian blue analogue (PBA) nanoporous framework material. They are considered as a developing non-noble catalyst with well-distributed active metal sites and extend the growth of high-performance electrocatalysts. To perceive the competent and stable earth-rich electrocatalysts for bifunctional electrochemical water splitting taking part in the necessary task for a sustainable energy conversion process is inevitable. Earlier reports have exposed that the low density of inert active sites and the low electrical conductivity of pure MHCF are major hurdles to make the commercial production effective. Based on previous work, hybrid NiHCF/S-doped g-C3N4 was produced by the coprecipitation technique and exhibits admirable electrocatalytic performance for OER and HER activities. From the electrochemical studies, the prepared NiHCF/S-doped g-C3N4 achieved a low 184 and 205 mV at 10 mA/cm2 and a low 76.7 and 57.6 mV/dec Tafel slope value for the OER and HER. Furthermore, the electrochemical active surface area of NiHCF/S-doped g-C3N4 was 180 and 41.75 cm2 which are estimated from the double-layer capacitance (Cdl) of 7.2 and 1.62 mF/cm2 corresponding to the OER and HER. Synergistic effect of the highly ordered graphitic carbon nitride and sulfur encourages rapid charge-carrier diffusion and binding of the adsorbed hydrogen intermediates for HER, leading to higher catalytic activity. This study brings a new approach using a simple strategy for fabrication and application of Prussian blue-based derivatives for proficient electrochemical water splitting.