Heteroatom doping regulates the catalytic performance of single-atom catalyst supported on graphene for ORR

Replacing fossil fuels with fuel cells is a feasible way to reduce global energy shortages and environmental pollution. However, the oxygen reduction reaction (ORR) at the cathode has sluggish kinetics, which limits the development of fuel cells. It is significant to develop catalysts with high catalytic activity of ORR. The single-atom catalysts (SACs) of Pt supported on heteroatom-doped graphene are potential candidates for ORR. Here we studied the SACs of Pt with different heteroatoms doping and screened out Pt-C-4 and Pt-C3O1 structures with only 0.13 V overpotential for ORR. Meanwhile, it is found that B atoms doping could weaken the adsorption capacity of Pt, while N or O atoms doping could enhance it. This regularity was verified on Fe SACs. Through the electronic interaction analysis between Pt and adsorbate, we explained the mechanism of this regularity and further proposed a new descriptor named corrected d-band center (e(d-corr)) to describe it. This descriptor is an appropriate reflection of the number of free electrons of the SACs, which could evaluate its adsorption capacity. Our work provides a purposeful regulatory strategy for the design of ORR catalysts.

Automated summary

Replacing fossil fuels with fuel cells is a feasible solution to reduce global energy shortages and environmental pollution. Catalysts with high catalytic activity of oxygen reduction reaction (ORR) are significant for the development of fuel cells. This study explored Pt single-atom catalysts (SACs) supported on heteroatom-doped graphene for ORR and identified Pt-C-4 and Pt-C3O1 structures with low overpotential. It was found that B doping weakens Pt's adsorption capacity, while N or O doping enhances it, which was verified on Fe SACs. The electronic interaction analysis and the proposed descriptor, corrected d-band center (e(d-corr)), explained the mechanism and provided a regulatory strategy for ORR catalyst design.