Defective-Engineered ZnO Encapsulated in N-Doped Carbon for Sustainable 2e<sup>–</sup> ORR: Interfacial Zn–N Bond Regulated Oxygen Reduction Pathways
Pan Xia, Tianwei He, Yu Sun, Xiaoguang Duan, Xi Chen, Zhong‐Shuai Zhu, Chao Wang, Y. Liu, Qiang He, Zhihong Ye
Abstract
Zinc oxide (ZnO), although known for its stability and safety, has shown limited catalytic activity in the two-electron oxygen reduction reaction (2e – ORR). In this context, we synthesized a robust defective-engineered ZnO/N-doped graphene heterojunction (ZnO-NG) featuring abundant Zn–N bonds at the interface. The engineered composite exhibited a remarkable H 2 O 2 yield of 13.1 mg h –1 cm –2 at 25 mA cm –2 with H 2 O 2 selectivity of 85.0%, surpassing NG and ZnO counterparts. Furthermore, the exceptional long-term stability of ZnO-NG was validated through chronoamperometric measurements and 10 successive runs, highlighting its great potential for large-scale H 2 O 2 synthesis. Density functional theory calculations and X-ray absorption near-edge structure analysis revealed that interfacial bridging N regulated the local electron distribution, transferring the unpaired electrons from Zn sites to the adjacent N/C atoms. The configuration facilitated the hydrogenation step of O 2 -to-OOH* and more importantly inhibited the O*-to–OH* conversion, thereby improving the selectivity in 2e – ORR toward water remediation.