Modulating electronic structure of cobalt silicate by iron-doping ensuring the boosted oxygen evolution reaction...

The development of cost-effective, high-efficiency oxygen evolution reaction (OER) catalysts through precise compositional and structural design via guest doping engineering represents a significant research challenge. While cobalt silicate (CoSi) has emerged as a promising OER catalyst, its practical application has been limited by relatively high overpotential (η). In this study, we presented a strategic Fe-doping approach to engineer the electronic structure of CoSi, significantly enhancing its OER performance. Through hydrothermal synthesis, we successfully incorporated Fe atoms into the CoSi framework, creating hollow spherical iron-doped cobalt silicate (CoSi-Fe) catalysts. Comprehensive characterization revealed that the geometric and synergistic effects of Fe-doping facilitate: (1) increased exposure of active sites, (2) enhanced activity of Co/Fe dual sites, and (3) improved structural stability of Co species. Density functional theory (DFT) calculations further demonstrated that Fe incorporation optimizes reaction kinetics and improves electrical conductivity, collectively boosting OER activity. The optimized CoSi-Fe-3 catalyst (Co/Fe = 15:5) exhibits exceptional performance, achieving an overpotential of only 289 mV at 10 mA cm^-2 (a 118 mV reduction compared to pristine CoSi of 407 mV) and superior to most reported metal silicate catalysts. We systematically analyzed the structure-activity relationship underlying this performance enhancement. This work establishes an effective doping strategy for developing high-performance silicate-based electrocatalysts, providing valuable insights for advancing renewable energy conversion technologies.