Conductive One-Dimensional Coordination Polymers with Tunable Selectivity for the Oxygen Reduction Reaction

Conductive materials involving nonprecious metal coordination complexes as electrocatalysts for the oxygen reduction reaction (ORR) have received increasing attention in recent years. Herein, we reported efficient ORR electrocatalysts containing M-S₂N₂ sites with tunable selectivity based on simple one-dimensional (1D) coordination polymers (CPs). The 1D CPs were synthesized from M(OAc)₂ and 2,5-diamino-1,4-benzenedithiol (DABDT) by a solvent thermal method. Due to their good electrical conductivities (10^-6-10^-2 S cm^-1), the 1D CPs could be used as ORR catalysts in low catalytic amounts without the addition of carbon materials. Cobalt-based CPs showed a well-organized structure of nanosheets with Co-S₂N₂ sites exposed and exhibited remarkable electrocatalytic ORR activity (E_onset = 0.93 V vs reversible hydrogen electrode (RHE), E_1/2 = 0.82 V, n = 3.85, J_L = 5.22 mA cm^-2, Tafel slope of 63 mV dec^-1) in alkaline media. However, nickel-based CPs favored a 2e^- ORR process with ∼87% H₂O₂ selectivity and an E_onset of 0.78 V. This work provides new opportunities for the construction of ORR catalysts based on conductive nonprecious metal CPs.