Electrochemical hydrogen storage using SrFe12O19 surface-immobilized polyoxometalate

A tri-nickel substituted Keggin-type polyoxometalate (PMo₉Ni₃O₃₇) was synthesized and subsequently immobilized on the surface of the M-type strontium hexaferrite (SrFe₁₂O₁₉) via the sol-gel method. The investigation of hydrogen storage capacity for the synthesized PMo₉Ni₃O₃₇@SrFe₁₂O₁₉ nanocomposite was conducted through electrochemical methodologies employing chronopotentiometry (CP). A conventional three-electrode configuration employing copper foam coated with PMo₉Ni₃O₃₇@SrFe₁₂O₁₉ served as the working electrode and was examined across a current range of ±1.5 mA. The charge and discharge of the experimental procedure indicated the substantial potential of the PMo₉Ni₃O₃₇@SrFe₁₂O₁₉ nanocomposite in the hydrogen storage process, which was determined 3125 mAh/g during the discharge phase. The successful synthesis was corroborated thorough FT-IR, UV–vis, XRD, SEM, EDX, and BET surface area analysis techniques by examining the characteristic absorption wavelengths or reflection patterns. The size of the nanoparticles was determined through SEM analysis yielding a diameter of 36.76 nm, and using the Scherrer equation, a diameter of 29.22 nm was obtained.