Integrating multiple regulatory strategies: phase, morphology and interface engineering to construct a hierarchical Ni 2 P–MoS 2 /rGO heterostructure catalyst for efficient oxygen reduction reaction

• Published in: Inorganic chemistry frontiers Vol. 11; no. 9; pp. 2763 - 2774
• Main Authors: Wang, Xinyi, Jin, Jing, Gao, Zeyuan, Hou, Li, Tao, Xiwen, Wang, Jing, Zhao, Yueqi, Gao, Faming
• Format: Journal Article
• Language: English
• Published: 30.04.2024
• ISSN: 2052-1553; 2052-1553
• DOI: 10.1039/D4QI00262H

Two-dimensional (2D) molybdenum disulfide (MoS 2 ) with a large surface area and unique electronic properties has emerged as a promising noble metal-free catalyst for electrochemical energy storage/conversion applications. However, the high reaction energy barrier and sluggish oxygen reduction reaction (ORR) kinetics severely limit its application in the field of fuel cells. Herein, a hierarchical Ni 2 P–MoS 2 /rGO hybrid catalyst with Ni 2 P nanoparticles uniformly supported on 2D layer 1T-MoS 2 /rGO composite nanosheets was elaborately designed via multiple regulatory strategies. The high-content metallic phase of MoS 2 (1T-MoS 2 ) nanosheets (78%) vertically anchored on the reduced graphene oxide (rGO) substrate, which is conducive to increasing the exposed active edges of MoS 2 and accelerating the electron transport. Meanwhile, the interface electron coupling effect between Ni 2 P and MoS 2 effectively generates numerous catalytically active centers via optimizing the electronic structure. Benefiting from the prominent synergistic effect of the phase, morphology, and interface engineering, the as-obtained Ni 2 P–MoS 2 /rGO hybrid demonstrates remarkable ORR catalytic activity and stability with a higher onset and half-wave potential of 0.916 V and 0.764 V, respectively, which are superior to those of the most reported MoS 2 -based catalysts. The modification of Ni 2 P on the 1T-MoS 2 /rGO composite triggers a transformation of the reaction pathway from two-electron for 1T-MoS 2 /rGO to direct four-electron, suggesting rapid reaction kinetics. The density functional theory (DFT) results further disclose that the rearrangement of the d band can be rationalized via the charge reconfiguration in the vicinity of the interfaces between Ni 2 P and MoS 2 , thereby greatly reducing the energy barrier of the ORR and enhancing the catalytic kinetics.