Ligand-orchestrated transition metal aerogels: a tailored sulfur coordination strategy for superior oxygen evolution catalysis

A novel strategy was developed to enhance oxygen evolution reaction (OER) performance using a tailored sulfur coordination strategy in ternary transition metal sulfide-oxide aerogels (TMS_1-<i>x</i>O_<i>x</i>). The structural and electronic properties of the aerogels synthesized by a metal coordination-initiated sol-gel method were precisely engineered by tuning Co content and controlling sulfur coordination sites. With increasing cobalt content, enhanced sulfur coordination around nickel facilitated the formation of spike-shaped nanostructures, resulting in superior catalytic performance. The optimized catalyst exhibited a low overpotential of 190 mV at 10 mA cm^-2, along with an enhanced electron transfer rate and exceptional stability exceeding 60 hours. Advanced characterization techniques, including X-ray photoelectron spectroscopy, X-ray absorption fine structure analysis, and density functional theory simulations, revealed that the ligand-orchestrated coordination environment around Ni plays a crucial role in modulating the electronic structure, thereby strengthening interactions with oxygen intermediates. The reaction followed the adsorbate evolution mechanism, demonstrating efficient catalysis with a reduced energy barrier for the rate-determining step. These findings underscore the importance of ligand-orchestrated coordination and structural engineering in developing high-performance OER catalysts.