A Cost‐Effective 3D Hydrogen Evolution Cathode with High Catalytic Activity: FeP Nanowire Array as the Active Phase

Abstract

Iron is the cheapest and one of the most abundant transition metals. Natural [FeFe]-hydrogenases exhibit remarkably high activity in hydrogen evolution, but they suffer from high oxygen sensitivity and difficulty in scale-up. Herein, an FeP nanowire array was developed on Ti plate (FeP NA/Ti) from its β-FeOOH NA/Ti precursor through a low-temperature phosphidation reaction. When applied as self-supported 3D hydrogen evolution cathode, the FeP NA/Ti electrode shows exceptionally high catalytic activity and good durability, and it only requires overpotentials of 55 and 127 mV to afford current densities of 10 and 100 mA cm(2) , respectively. The excellent electrocatalytic performance is promising for applications as non-noble-metal HER catalyst with a high performance-price ratio in electrochemical water splitting for large-scale hydrogen fuel production.

Bi‐Functional Iron‐Only Electrodes for Efficient Water Splitting with Enhanced Stability through In Situ Electrochemical Regeneration

“…The world's most abundant energy source, solar energy, suffers from the issue of intermittency. Two highly debated approaches in the solar fuels fi eld in acidic solutions (0.5 M H 2 SO 4 ), [ 35 ] however, the applicability of FeP in water splitting is currently limited as it is only active in acidic to neutral pH, [35][36][37] where nonprecious metal OER catalysts do not typically operate. [ 30 ] Further, the scalability of phosphide materials is limited by toxicity and availability.…”

“…Hence iron is arguably the most attractive element on which to base sustainable catalysts, due to its effectively inexhaustible supply, low toxicity, and negligible environmental impact. Despite this, iron-based catalysts have been relatively underreported and underused, probably due to their notoriety for corrosion.Iron-based electrodes for either the HER or the OER have been reported, [35][36][37][38][39][40] but bi-functionally active iron-only materials in water splitting are unknown. For example, FeP is described as a promising high activity noble-metal-free material Scalable and robust electrocatalysts are required for the implementation of water splitting technologies as a globally applicable means of producing affordable renewable hydrogen.…”

Highly branched cobalt phosphide nanostructures for hydrogen-evolution electrocatalysis

“…For example, phosphides of nickel, 1-3 cobalt, 4-12 iron, 13,14 copper, 15 molybdenum, [16][17][18] and tungsten 19 have been found to electrocatalytically generate H 2 (g) with low overpotentials at operationally relevant current densities for solar-driven water splitting systems, while exhibiting high stability under strongly acidic conditions. Metal phosphides therefore offer an earthabundant and inexpensive alternative to platinum, which serves as the benchmark catalyst for the hydrogen-evolution reaction (HER).…”

Electrodeposited Cobalt‐Phosphorous‐Derived Films as Competent Bifunctional Catalysts for Overall Water Splitting

“…), [5] FeS, [6] CoS, [7] Ni 3 S 2 , [8] MoC and MoB, [9] MoP, [10] WP and WP 2 , [11] CoP and Co 2 P, [12] Ni 2 P, [13] FeP, [14] andC u 3 P. [15] On theo ther hand, many OER catalysts based on the oxides/hydroxides of cobalt, [16] nickel, [17] manganese, [18] iron, [19] and copper [20] have also been reported with OER catalytic activities under basic conditions.H owever,t oa ccomplish overall water splitting, the coupling of HER and OER catalysts in the same electrolyte is desirable.T he current prevailing approaches often result in incompatible integration of the two catalysts and lead to inferior overall performance.I tr emains ag rand challenge to develop bifunctional electrocatalysts active for both HER and OER.…”