Synergistic coupling ensuing cobalt phosphosulfide encapsulated by heteroatom-doped two-dimensional graphene shell as an excellent catalyst for oxygen electroreduction

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2021-11, Vol.423, p.130233, Article 130233
• Main Authors: Maiti, Kakali, Kim, Kyeounghak, Noh, Kyung-Jong, Han, Jeong Woo
• Format: Article
• Language: English
• Subjects: Co-P-S; Crystal-phase engineering; Doped graphene; Fuel cell; Heteroatom doping; Oxygen reduction reaction
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.130233

[Display omitted] •Cobalt phosphosulfide encapsulated heteroatom-doped graphene was prepared for ORR.•Cobalt phosphosulfide on GN,S,P sheets altered crystallinity due to the P-S interaction.•The imbalanced charge distortion on the doped graphene network was elucidated by DFT.•The Co−P−S unit was suitably phase-engineered by activating Co3+/Co2+ couple.•CPS@GN,S,P catalyst showed the enhanced ORR activity and durability. We synthesized cobalt phosphosulfide (CPS) encapsulated in heteroatom-doped (N, S, P) graphene (CPS@GN,S,P) to achieve highly synergistic and durable catalyst for the oxygen reduction reaction (ORR). The catalyst was precisely tuned using Co metal (M) and suitably integrated with P and S by a simple method of thiourea-phosphate-assistance, followed by reductive annealing at 700 °C. The possible P-S interactions simultaneously altered the cobalt phosphide crystallinity and improved the defective CPS nanocrystal’s interface in the CPS@GN,S,P catalyst. Theoretical investigation demonstrated that doping can induce imbalanced charge distortion on the graphene network and yield thermodynamically-favorable O2 adsorption and dissociation. The non-stoichiometric CPS nanoparticles with M−P−S unit that had been appropriately phase-engineered by controlling the Co3+/Co2+ couple activation with effective electronic structure tuned, could enhance the multiple oxygen-adsorption electroactive sites for catalyzation. Such integrated catalyst can yield an efficiently synergistic ORR with high mass/charge transfer, excellent methanol stability and durability comparable to commercial Pt/C in alkaline medium. CPS@GN,S,P is a promising alternative to Pt as a catalyst for ORR in fuel cells and metal-air batteries.