Sulfur-Induced Electronic Optimization of N-Doped Carbon with CoP/Co 2 P Heterostructure by Precursor Design for Rechargeable Zinc-Air Batteries.

Heteroatom doping and heterostructure construction are the key methods to improve the performance of electrocatalysts. However, developing such catalysts remains a challenging task. Herein, we designed two comparable polymers, phytic acid/thiourea polymer (PATP) and phytic acid/urea polymer (PAUP), as precursors, which contain C, N, S/O, and P by microwave heating. To pinpoint how the introduction of sulfur would affect the electronic structure and catalytic activity, these two polymers were physically blended with CoCo-Prussian blue analogue (CoCo-PBA) and further calcination, respectively. The highly dispersed CoP/Co 2 P-rich interfacial catalysts anchored on the N,S-codoped or N-doped carbon support were successfully prepared (CoP/Co 2 P@CNS and CoP/Co 2 P@CN). The prepared CoP/Co 2 P@CNS catalyst showed good ORR properties ( E 1/2 = 0.856 V vs RHE) and OER properties ( E j 10 = 1.54 V vs RHE), which were superior to the commercial Pt/C and RuO 2 catalysts. The reversible oxygen electrode index (Δ E = E j 10 - E 1/2 ) can reach ∼0.684 V. Meanwhile, the rechargeable zinc-air battery assembled with a CoP/Co 2 P@CNS catalyst as the air cathode also showed excellent performance, with a charge-discharge cycle stability of up to 900 h. DFT calculations further confirm that the introduction of S atoms can affect the electronic structure and enhance the catalytic activity of C and N atoms on carbon support.