The searching of highly efficient catalysts for oxygen reduction reaction(ORR) has attracted particular attention. In this work, we construct the graphene-based bilayers BG/X that consists by the CoN_(4) embedded grap...The searching of highly efficient catalysts for oxygen reduction reaction(ORR) has attracted particular attention. In this work, we construct the graphene-based bilayers BG/X that consists by the CoN_(4) embedded graphene as the upper layer and the X modified graphene as the bottom layer(X = Si, P, S). The interfacial bonding between CoN_(4) site and the X dopant is spontaneously formed due to the strong pd hybridization, which changes the Co ligand from the planar-four N_(4) coordination into spatial-five N_(4)+X one. The additive glue atom weakens too strong adsorptions of the ORR intermediates on CoN_(4) site and thereby improves the ORR activities in comparison with the monolayer counterpart. From the free energy profiles, the overpotentials η are 0.47, 0.49 and 0.45 V for BG/Si_(a), BG/P_(a) and BG/S_(a), respectively,being comparable to that of state-of-the-art Pt material. Besides, the kinetic barriers for the bilayers are less than 0.75 eV, an indicative of the room temperature activity. Furthermore, the combination of thermodynamic and kinetic analysis ensures the preference of 4e^(-)-OOH associative mechanism over 2e^(-)-H_(2)O_(2) mechanism, being beneficial for membrane stability against the H_(2)O_(2) corrosion. Therefore,the graphene-based bilayers deliver the high efficiencies for oxygen reduction electrocatalysis.Therefore, the interfacial bonding in the graphene-based bilayers provides an interesting strategy to suppress the poisoning phenomenon for the material design from atom scale.展开更多
基金the supports from the National Natural Science Foundation of China (51701152, 21503097, 51631004, 21806023, 51702345)Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX20_3160)。
文摘The searching of highly efficient catalysts for oxygen reduction reaction(ORR) has attracted particular attention. In this work, we construct the graphene-based bilayers BG/X that consists by the CoN_(4) embedded graphene as the upper layer and the X modified graphene as the bottom layer(X = Si, P, S). The interfacial bonding between CoN_(4) site and the X dopant is spontaneously formed due to the strong pd hybridization, which changes the Co ligand from the planar-four N_(4) coordination into spatial-five N_(4)+X one. The additive glue atom weakens too strong adsorptions of the ORR intermediates on CoN_(4) site and thereby improves the ORR activities in comparison with the monolayer counterpart. From the free energy profiles, the overpotentials η are 0.47, 0.49 and 0.45 V for BG/Si_(a), BG/P_(a) and BG/S_(a), respectively,being comparable to that of state-of-the-art Pt material. Besides, the kinetic barriers for the bilayers are less than 0.75 eV, an indicative of the room temperature activity. Furthermore, the combination of thermodynamic and kinetic analysis ensures the preference of 4e^(-)-OOH associative mechanism over 2e^(-)-H_(2)O_(2) mechanism, being beneficial for membrane stability against the H_(2)O_(2) corrosion. Therefore,the graphene-based bilayers deliver the high efficiencies for oxygen reduction electrocatalysis.Therefore, the interfacial bonding in the graphene-based bilayers provides an interesting strategy to suppress the poisoning phenomenon for the material design from atom scale.
