An iodine-treated metal-organic framework with enhanced catalytic activity for oxygen reduction reaction in alkaline electrolyte. (20th March 2020) - He, Xiaobo
Abstract: Herein, a zeolite-like metal-organic framework (MOF, i.e., ZIF-67) is treated with I2 at 170 °C and without any solvents and inert atmospheres to obtain the oxygen reduction reaction (ORR) catalysts (i.e., I2 &ZIF-67). After treated with I2, the ORR activity of I2 &ZIF-67 in alkaline electrolyte has been significantly increased compared with the pristine ZIF-67. Particularly, the optimized I2 &ZIF-67(2:1) shows the half-wave potential of ∼0.83 V and Tafel slope of ∼37.3 mV per current decade, which is comparable to 20 wt% Pt/C. The enhanced ORR activity is mainly attributed to the generation of active pyridinic-N, Co 2+ and I3 − species induced by the interaction between I2 and ZIF-67. Moreover, the I2 treatment also facilitates the charge and mass transfer for ORR. This work provides a strategy to develop highly efficient ORR catalysts derived from MOFs at low temperature. Graphical abstract: An iodine-treated ZIF-67 with enhanced activity toward oxygen reduction reaction was developed without solvents and inert atmospheres at low temperature. Image 1 Highlights: Iodine-treated ZIF-67 is developed as amorphous catalyst for ORR. The optimal I2 &ZIF-67(2:1) shows much higher ORR activity than pristine ZIF-67. The key roles of iodine treatment in boosting ORR activity are highlighted.