Designing Highly Efficient and Long‐Term Durable Electrocatalyst for Oxygen Evolution by Coupling B and P into Amorphous Porous NiFe‐Based Material

Abstract

Oxygen evolution reaction (OER) is of great significance for hydrogen production via water electrolysis, which, however, demands development of highly active, durable, and cost‐effective electrocatalysts in order to stride into a renewable energy era. Herein, highly efficient and long‐term durable OER by coupling B and P into an amorphous porous NiFe‐based electrocatalyst is reported, which possesses an amorphous porous metallic bulk structure and high corrosion resistance, and overcomes the issues associated with currently used catalyst nanomaterials. The PB codoping in the activated NiFePB (a‐NiFePB) delocalizes both Fe and Ni at Fermi energy level and enhances p–d hybridization as simulated by density functional theory calculations. The harmonized electronic structure and unique porous framework of the a‐NiFePB consequently improve the OER activity. The activated NiFePB thus exhibits an extraordinarily low overpotential of 197 mV for harvesting 10 mA cm−2 OER current density and 233 mV for reaching 100 mA cm−2 under chronopotentiometry condition, with the Tafel slope harmoniously conforming to 34 mV dec−1. Impressive long‐term stability of this new catalyst is evidenced by only limited activity decay after 1400 h operation at 100 mA cm−2. This work strategically directs a way for heading up a promising energy conversion alternative.

High Density and Unit Activity Integrated in Amorphous Catalysts for Electrochemical Water Splitting

“…Peng and co‐workers [ 159 ] further reported the highly efficient and long‐term durable OER electrocatalyst via coupling B and P into an amorphous NiFe‐based bulk. The unique NiFeO x H y (shell)/NiFePB (core) configuration ( Figure a–e) significantly increases the activity by using the coupling of P and B atoms that can regulate the electronic structures of the active sites and the conductivity of materials (Figure 20f–h).…”

Recent Progress on NiFe‐Based Electrocatalysts for the Oxygen Evolution Reaction

“…Increasing levels of attention have also been directed to amorphous catalysts, which tend to possess a number of uncoordinated metal atoms with greater numbers of exposed active sites on their surfaces. [179] For example, Peng and co-workers reported a highly efficient and durable OER catalyst by codoping B and P into an amorphous porous NiFe-based electrocatalyst (a-NiFePB), which exhibited an amorphous porous metallic bulk structure and a high corrosion resistance. [179] DFT calculations indicated that P and B codoping delocalized both Fe and Ni at the Fermi energy level and resulted in enhanced p-d hybridization.…”

“…[179] For example, Peng and co-workers reported a highly efficient and durable OER catalyst by codoping B and P into an amorphous porous NiFe-based electrocatalyst (a-NiFePB), which exhibited an amorphous porous metallic bulk structure and a high corrosion resistance. [179] DFT calculations indicated that P and B codoping delocalized both Fe and Ni at the Fermi energy level and resulted in enhanced p-d hybridization. The modified electronic structure and unique porous framework of a-NiFePB therefore contributed to its excellent OER performance, which required a low overpotential of 197 mV to achieve a current density of 10 mA cm −2 , and 233 mV for 100 mA cm −2 , with a small Tafel slope of 34 mV dec −1 .…”

Electronic Structure Tuning of 2D Metal (Hydr)oxides Nanosheets for Electrocatalysis

“…Recently, amorphization of either the outer surfaces or the whole catalysts can reasonably destroy the periodicity of the crystal structure and alter the electron distribution of the amorphous zone. [149][150][151][152] In this way, the activity of the electrocatalyst can drastically increase. Amorphization has been demonstrated to be an effective alternative to optimize electrocatalysts.…”