Ni₁₂P₅ and Ni₁₂P₅-rGO for multifunctional electrocatalyst and supercapacitor application

Transition metal phosphides are crucial for various environmental and energy applications. In this study, porous Ni₁₂P₅ and Ni₁₂P₅-rGO were synthesized using a one-step solvothermal method. Red phosphorus served as the phosphorus source, while ethylene glycol acted as a capping agent to promote the formation of nanomaterials within a nitrogen-rich atmosphere. The catalytic performance of these materials was evaluated through their hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and capacitance properties. Notably, Ni₁₂P₅-rGO exhibited Tafel slopes of 66 mV/dec for OER and 33 mV/dec for HER, indicating enhanced charge transfer efficiency compared to Ni₁₂P₅, which showed slopes of 78 mV/dec and 102 mV/dec, respectively. This improvement suggests that Ni₁₂P₅-rGO facilitates faster electron transfer, resulting in superior catalytic performance. Additionally, the synergistic effect of reduced graphene oxide (rGO) contributes to improved charge storage capabilities. The Ni₁₂P₅-rGO demonstrated a specific capacitance of 192 F/g, significantly higher than the 110 F/g observed for Ni₁₂P₅ at a current density of 1 A/g. Remarkably, these materials maintained their capacity over 5000 cycles, achieving a commendable 98 % coulombic efficiency. These findings highlight the potential of Ni₁₂P₅-rGO as an effective material for energy conversion and storage applications, showcasing its promising role in advancing the efficiency of related technologies.