Encapsulated FeP nanoparticles with in-situ formed P-doped graphene layers: Boosting activity in oxygen reduction reaction

Abstract

Nonprecious metal-based oxygen reduction reaction (ORR) electrocatalysts with high efficiency in both alkaline and acidic media are being intensively studied for the purpose of replacing expensive Pt-based catalysts; however, it is still a challenge to achieve superior ORR performances, especially in acidic media. Herein, by pyrolysis of mixed precursors of diammonium phosphate, melamine and hemin, we prepared a nanocomposite catalyst (denoted as FeP@PGL) composed of nitrogen-doped carbon nanosheets with embedded FeP nanoparticles (NPs), which were encapsulated by in-situ formed phosphorus-doped graphene layers. It is found that phosphorous was preferentially doped in the coating layers on FeP NPs, instead of in the carbon nanosheets. The FeP@PGL catalyst exhibited excellent ORR performance, with the onset and half-wave potential up to 1.01 and 0.90 V vs. the reversible hydrogen electrode (RHE) in alkaline media, and 0.95 and 0.81 V vs. RHE in acidic media, respectively. By thorough microscopy and spectroscopy characterizations, the interfacial charge transfer between the encapsulated FeP NPs and P-doped graphene layers was identified, and the local work function of the catalyst surface was also reduced by the interfacial interaction. The interfacial synergy between the encapsulated FeP and phosphorus-doped graphene layers was essential to enhance the ORR performance. This study not only demonstrates the promising ORR properties of the encapsulated-FeP-based nanocomposite catalyst, but also provides direct evidence of the interfacial charge transfer effect and its role in ORR process.

Atomically Dispersed Selenium Sites on Nitrogen‐Doped Carbon for Efficient Electrocatalytic Oxygen Reduction

“…The calculated n value of Se@NC‐1000 is ca. 4 and the hydrogen peroxide production rate is close to that of Pt/C (Figure 4e), further confirming its highly efficient four‐transfer ORR mechanism [7a] . The ORR polarization curve after 5000 cycles almost coincides with the original one (Figure 4f), revealing the remarkable long‐term catalytic durability.…”

Understanding the electrocatalytic mechanism of self-template formation of hierarchical Co9S8/Ni3S2heterojunctions for highly selective electroreduction of nitrobenzene

“…The low work function of Co 9 S 8 /Ni 3 S 2 -NF indicates a rapid electron donation capacity from the catalyst surface to the adsorbed nitro groups. 67,68 Therefore, theoretical calculations and experiments together show that the construction of the Co 9 S 8 /Ni 3 S 2 heterojunction facilitates the efficient reduction of PhNO 2 to PhNH 2 .…”

“…Fig.S31† shows that the work functions of Co 9 S 8 /Ni 3 S 2 -NF, Co 9 S 8 /Ti and Ni 3 S 2 /NF catalysts were calculated to be 6.77, 6.28 and 5.89 eV, severally. The low work function of Co 9 S 8 /Ni 3 S 2 -NF indicates a rapid electron donation capacity from the catalyst surface to the adsorbed nitro groups 67,68. Therefore, theoretical calculations and experiments together show that the construction of the Co 9 S 8 /Ni 3 S 2 heterojunction facilitates the efficient reduction of PhNO 2 to PhNH 2 .…”

Phosphorus-Doped Graphene Electrocatalysts for Oxygen Reduction Reaction

“…The optimized Cu 3 P@P, N-graphene shows comparable catalytic activity to that of the Pt/C catalyst because of the synergistic effect between the Cu 3 P and P, N-graphene shell. Later, similar strategies were used by different groups to prepare Co@N, P, S -graphene, FeCo@P, N-graphene/N-CNTs, and FeP@P-graphene [ 108 , 109 , 110 ]. Interestingly, these materials are always used as bifunctional catalysts, such as OER, HER, and triiodide reduction reaction (TIRR).…”