A porous heterostructure catalyst for oxygen evolution: synergy between IrP₂ nanocrystals and ultrathin P,N-codoped carbon nanosheets

Abstract

Designing efficient and robust oxygen evolution reaction (OER) electrocatalysts is of great importance for various electrochemical energy storage and conversion applications. Herein, we developed IrP2 nanocrystals uniformly anchored in P,N-codoped carbon nanosheets (IrP2@PNC-NS) as highly active OER electrocatalysts. The ultrathin PNC-NS reconstructs an agaric-like porous structure, which can inhibit the agglomeration of the IrP2 nanocrystals effectively. Moreover, the in-situ phosphatization leads to the formation of a strong electron interaction between PNC-NS and IrP2 nanocrystals, endowing the heterostructure materials with satisfying synergistic effects. Benefiting from the collaborative advantages of ideal configuration structure and favorable synergistic effects, IrP2@PNC-NS exhibits excellent OER performance with a low overpotential of 221 mV at 10 mA cm−2, and a small Tafel slope of 37.5 mV dec−1. DFT calculations reveal that the synergistic effects derived from the IrP2/PNC interfaces, which can effectively tune the activation barriers towards facilitating the oxygen evolution process. This work provides new insight into the design of heterostructure materials for advanced OER electrocatalysts.

Iridium‐based electrocatalysts toward sustainable energy conversion

“…Apart from doping heteroatoms into the support, non‐metal heteroatoms can be combined with Ir to prepare complexes, such as IrP 2 . Just in 2021, Wang and coworkers reported IrP 2 nanocrystals with a ~ 3 nm diameter size (crystal information: monoclinic system, space group: P2 1 / c [14], a = 5.745, b = 5.791, c = 5.849, α = γ = 90°, β = 111.57°, JCPDS: 89‐3985) 185 . After embedding IrP 2 onto N, P‐doped carbon support, the final catalyst surprisingly possesses high activity for OER.…”

“…Just in 2021, Wang and coworkers reported IrP 2 nanocrystals with a ~3 nm diameter size (crystal information: monoclinic system, space group: P2 1 /c [14], a = 5.745, b = 5.791, c = 5.849, α = γ = 90 , β = 111.57 , JCPDS: 89-3985). 185 After embedding IrP 2 onto N, P-doped carbon support, the final catalyst surprisingly possesses high activity for OER. In alkaline conditions, it only needs a low overpotential of 221 mV to reach a current density of 10 mA cm À2 and can also maintain its stability over a 50 h long-time i-t test.…”