Designing and Understanding the Outstanding Tri-Iodide Reduction of N-Coordinated Magnetic Metal Modified Defect-Rich Carbon Dodecahedrons in Photovoltaics

Nitrogen-coordinated metal-modified carbon is regarded as a novel frontier electrocatalyst in energy conversion devices. However, the construction of intrinsic defects in a carbon matrix remains a great challenge. Herein, N-coordinated magnetic metal (Fe, Co) modified porous carbon dodecahedrons (Fe/Co-NPCD) with a large surface area, rich intrinsic defects, and evenly distributed metal-N x species are successfully synthesized via the rational design of iron precursor and the bimetallic-organic frameworks. Because of a synergistic effect between N-coordinated dual magnetic metal active sites, the Fe/Co-NPCD exhibits exceptional electrocatalytic activity and electrochemical stability. A solar cell fabricates with the Fe/Co-NPCD yields an impressive power conversion efficiency of 8.35% in dye-sensitized solar cells, superior to that of mono-metal-doped carbon-based cells and conventional Pt-based cells. Furthermore, density functional theory calculations illustrate that Fe, Co, and N doping are in favor of improving the adsorption capacity of the catalyst for I 3 − species by optimizing the magnetic momentum between the magnetic metal atoms, thereby upgrading its catalytic activity. This work develops a general strategy for synthesizing a high-performance defect-rich carbon-based catalyst, and offers valuable insight into the role of magnetic metals in catalysis, which can be used to guide the design of high-performance catalysts in the energy field.