Modulation of Disordered Coordination Degree Based on Surface Defective Metal–Organic Framework Derivatives toward Boosting Oxygen Evolution Electrocatalysis

Seeking potential electrocatalysts with both large-scale application and robust activity for the oxygen evolution reaction allows for no delay. Herein, a squarate-based metal-organic framework (MOF) ([Co₃ (C₄ O₄ )₂ (OH)₂ ]⋅3H₂ O) is reported for electrocatalytic water oxidation. A facile, green, and low-cost strategy is proposed to introduce defects by not only rationally breaking CoO bonds to form defective coordination environment and electronic reconfiguration, but also systematically modulates defect concentration to optimize electrochemical performance. As a result, the post-treated surface defective MOF derivative (Co-MOF-3h) achieves a current density of 50 mA cm^-2 at an overpotential of 380 mV, owing to larger active surface area, more opened active sites, and favorable conducting channels. Finally, density functional theory calculations have further validated the effect of defective coordination in regard to electronic structure for electrocatalysts. This study delivers inspirations in defect engineering and is in favor of developing high-efficiency electrocatalysts.