Highly Durable Compositionally Variant Bifunctional Tetrametallic Ni–Co–Mn–Fe Phosphide Electrocatalysts Synthesized by a Facile Electrodeposition Method for High-Performance Overall Water Splitting

Abstract

In the recent few decades, the demand for green sources of energy that are clean and sustainable became very essential to reduce the greenhouse and global warming problems. Consequently, there is an increasing demand to identify nonprecious, cheap bifunctional electrocatalysts for water splitting. Herein, nanosheets of different earth-abundant Ni, Co, Mn, and Fe combinations are electrodeposited over commercial Ti mesh and tested for the overall water splitting. The bare Ti mesh requires overpotentials of −486.6 mV at −10 mA cm −2 and 534.5 mV at 10 mA cm −2 for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. However, the electrodeposited catalysts show much higher catalytic activity for both HER and OER with overpotentials of −300 and 279 mV at −10 and 10 mA cm −2 , respectively, lowering the overpotential needed to drive the OER by 50%. Nevertheless, to enhance the electrocatalytic performance of the fabricated catalysts, they are phosphidized using different phosphorous precursors. The resulted NiCoMnFe−P catalysts exhibit much lower HER overpotential (−200 mV at −10 mA cm −2 ), which is 40% lower than that needed by the bare Ti mesh. For the overall water splitting, a cell voltage of 1.71 V is recorded to achieve a current density of 10 mA cm −2 . Lastly, the stability test of the overall device reveals very high stability with current retention of 90% over 22 h of continuous electrolysis. Furthermore, the synergy between the metallic components in the absence and presence of P is elucidated using density functional theory calculations, revealing optimized G H* and G Hd 2 O* for the HER reaction over the P-top site of the MnFeCoNiP catalyst. In addition, the calculations explain the superiority of the NiCoMnFe catalyst over the NiCoMnFeP counterpart for the OER.

Tuned Bimetallic Fe–Ni Thiophosphides as Advanced Battery Materials for Asymmetric Electrochemical Supercapacitors with Outstanding Energy Density

“…However, the sluggish reaction kinetics and low electrical conductivity of TMS result in poor rate capability. 15 On the other hand, transition metal phosphides (TMP) showed good performance in supercapacitors due to their high electrical conductivity that leads to fast electron transport and highpower density. 16−18 To combine the merits of both TMS and TMP, metal thiophosphides have recently been investigated as electrode materials in energy storage and conversion devices.…”

“…Due to their very rich redox chemistry, TMS usually exhibit high specific capacitance and energy density when used as supercapacitor electrodes. However, the sluggish reaction kinetics and low electrical conductivity of TMS result in poor rate capability . On the other hand, transition metal phosphides (TMP) showed good performance in supercapacitors due to their high electrical conductivity that leads to fast electron transport and high-power density. − To combine the merits of both TMS and TMP, metal thiophosphides have recently been investigated as electrode materials in energy storage and conversion devices. − The existence of both S and P anions with different proportions is expected to efficiently tune the electronic and electrochemical properties, leading to catalytic activity and stability superior to those of the corresponding sulfides and phosphides.…”

Recent Advances in Manganese-Based Materials for Electrolytic Water Splitting

“…Defect engineering can also optimize the charge distribution around the active site, accelerate the charge transfer rate, and change the morphology and structure of the material. The resulting abundant lattice dislocation and surface vacancy are conducive to the acceleration of the electron transfer and enhancement of the catalytic performance of the OER and the HER [ 66 , 121 , 122 , 123 , 124 , 125 ]. Finally, phase engineering regulates the different morphologies of catalytic materials by changing the reaction temperature.…”

Three-dimensional porous metal phosphide cathode electrodes prepared via electroless galvanic modification for alkaline water electrolysis

“…31,32 Such foams having a three-dimensional (3D) network structure have high electronic conductivity, controllable electrochemical properties, exceptional mechanical strength, high surface area and high porosity, making them suitable as excellent catalyst supports. 14,33,34 When it comes to the HER in water electrolysis, transition metal-based catalysts over conductive 3D porous supports including nickel foams have very recently shown great promise and even overtake noble metal based catalyst performances. 30,35,36…”

“…31,32 Such foams having a three-dimensional (3D) network structure have high electronic conductivity, controllable electrochemical properties, exceptional mechanical strength, high surface area and high porosity, making them suitable as excellent catalyst supports. 14,33,34 When it comes to the HER in water electrolysis, transition metal-based catalysts over conductive 3D porous supports including nickel foams have very recently shown great promise and even overtake noble metal based catalyst performances. 30,35,36 In the present study, we applied a sequential approach wherein the combination of electroless galvanic replacement (GR) and annealing processing techniques was used to create a high-performing, versatile, low Ru-loaded, and self-supported metal phosphide electrode (catalyst + porous transport layers) using porous 3D nickel foam (Ni 2 P-Ru/NF) susbstrate.…”