Phosphorus-modified Basic Nickel Silicate Derivated from Vermiculite for Efficient Oxygen Evolution Reaction

The pursuit of clean and sustainable energy sources has intensified the research focus on water electrolysis, particularly the oxygen evolution reaction (OER), which serves as a pivotal step in hydrogen generation. However, the development of efficient and cost-effective OER catalysts remains a major bottleneck hindering the widespread adoption of water electrolysis technology. In this work, utilizing vermiculite (VMT), an abundant and environmentally friendly clay mineral, was employed as the precursor to obtain SiO ₂ (V-SiO ₂ ). We have successfully synthesized a novel phosphate-modified layered nickel silicate Ni ₃ Si ₂ O ₅ (OH) ₄ (NiSi-P) derived from the VMT through a combination of hydrothermal and vapor deposition method. Electrochemical evaluations in 1.0 M KOH revealed that NiSi-P exhibited remarkable OER performance, achieving a low overpotential of 334 mV at 10 mA·cm ^-2 , significantly outperforming unmodified nickel silicate (NiSi, 564 mV). This improvement is attributed to the unique structural features and surface chemistry of NiSi-P, which facilitate efficient charge transfer and protonation/deprotonation during the catalytic process. This study provided an idea for the application of low-cost silicate materials in electrocatalytic water splitting in OER.