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-C₄ 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 (ε_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.