Encapsulating hollow (Co,Fe)P nanoframes into N,P-codoped graphene aerogel for highly efficient water splitting

Exploring highly efficient, stable and nonprecious electrocatalysts for both hydrogen and oxygen evolutions is greatly desirable for sustainable energy conversion, but still a huge challenge. Herein, we construct a unique three-dimensional (3D) porous electrocatalyst with hollow (Co,Fe)P nanoframes encapsulated into N,P-codoped graphene aerogel (CFP NFs@NPGA) through one-step in situ encapsulation and selective etching, followed by phosphorization. Due to its uniqure 3D porous nanoarchitecture, CFP NFs@NPGA displays superior electrocatalytic performance. As a highly efficient catalyst for hydrogen evolution reaction , the CFP NFs@NPGA catalyst only needs low overpotential of 155 mV to afford 10 mA cm −2 under alkaline condition. Meanwhile, the hybrid reveals remarkable oxygen revolution reaction activity with a small overpotential of 278 mV to afford 10 mA cm −2 in alkaline electrolyte . When adopted as both cathode and anode in overall water-splitting cell, the hybrid requires only 1.59 V to achieve 10 mA cm −2 with nearly 100% faradaic efficiency, and the experimentally measured H 2 and O 2 gas genenaration rates are about 0.18 and 0.09 mmol h −1 , respectively, showing outstanding long-term stability even over 48 h. The present results manifest that the combination of hollow nanostructure and hetero-atom-doped carbon matrix is an effective strategy to enhance water-splitting performance of transition metal phosphides.