The Activity Improvement of the TM3(hexaiminotriphenylene)2 Monolayer for Oxygen Reduction Electrocatalysis: A Density Functional Theory Study

摘要

Polymer electrolyte membrane fuel cells (PEMFCs) are one of the most prominent clean energy technologies to achieve the hydrogen utilization, to solve the low efficiency and high pollution of the fossil fuel combustion. In order to address PEMFC commercialization, especially for the automobile application, developing high activity and selectivity catalysts for the oxygen reduction reaction (ORR) is of critical importance. Based on density functional theory, the catalytic activity of the conductive two-dimensional metal-organic frameworks TM3(HITP)2 monolayer (where HITP = hexaiminotriphenylene; TM = Ni, Co, Fe, Pd, Rh, Ru, Pt, Ir and Os) for ORR have been investigated systematically. The classical volcano curve of the ORR activity as a function of the OH binding are found where the Ni, Pd and Pt located at the weak binding side are suffered from the sluggish *OOH formation and prefers the inefficient 2e- mechanism while for other elements belonged to the strong binding side, the reaction are hindered by the poison of ORR intermediates. Herein, the Co, Rh and Ir central atoms exhibit the enhanced catalytic activity in combination of the desirable selectivity of the O2 reduction to H2O, with an activity order of Ir > Co ≈ Rh > Ni. This systematical work may open new avenues for the development of high-performance non-PGM catalysts for practical applications of ORR.