Bimetallic FeNiP nanosheet arrays on a nickel foam (FeNiP@NFO) are fabricated by an in situ oxidative etching process coupled with phosphorization. The self-supported FeNiP@NFO catalyst exhibits prominent catalytic activity for a hydrogen evolution reaction with overpotentials as low as 64, 82, and 54 mV at 10 mA·cm–2 in 1.0 M PBS, 1.0 M KOH, and 0.5 M H2SO4, respectively, surpassing most reported non-noble catalysts. Moreover, FeNiP@NFO requires an overpotential of 193 mV in 1.0 M KOH to drive 10 mA·cm–2 for an oxygen evolution reaction. The overall water-splitting electrolyzer assembled with FeNiP@NFO as both the anodic and cathodic electrodes exhibits an extremely low cell voltage of 1.49 V to achieve a current density of 10 mA·cm–2, which is much lower than that of most alkaline electrolysis systems. The extraordinary electrocatalytic activity of FeNiP@NFO is ascribed to the synergistic effect between elements and the special network compiled by nanosheet arrays, which offers high conductivity, abundant accessible active sites, easy hydrogen release channels, and fast electron transportation. 

Self-Supported FeNiP Nanosheet Arrays as a Robust Bifunctional Electrocatalyst for Water Splitting

Bifunctional oxygen catalysts with excellent catalytic activity and durability towards both oxygen reduction and oxygen evolution reactions (ORR/OER) are pivotal for long-term rechargeable Zn-air batteries. Herein, we report a spherical carbon decorated with FeP and CoP nanoparticles (denoted as FeCoP/NPC) as an ORR/OER bifunctional electrocatalyst for rechargeable Zn-air batteries. HCTCz@Fe/Co-PA is first produced by the modification of phytic acid (PA) onto (into) a porous cross-linked polymeric sphere of poly(bis(N-carbazolyl)-1,2,4,5-tetrazine) (HCTCz), followed by chelating with metal ions (i.e., Fe3+ and Co2+). The subsequent pyrolysis yields FeCoP/NPC, which shows prominent activity and reliability for the ORR and OER due primarily to the synergistic effect of FeP and CoP active sites and N/P co-doped carbon. The aqueous Zn-air battery assembled with FeCoP/NPC provides high specific capacity and peak power density. Notably, the constructed Zn-air battery can be repetitively charged and discharged for 1200 h at 5 mA cm-2. In addition, a flexible solid-state Zn-air battery made from FeCoP/NPC exhibits a power density of 74 mW cm-2 and repeatedly works for 90 h at 2 mA cm-2. This work opens up an avenue for the preparation of highly efficient bifunctional electrocatalysts for Zn-air batteries considering the extensive N-rich polymer precursors and various metal phosphide nanoparticles.

Hypercrosslinked polymer-mediated fabrication of binary metal phosphide decorated spherical carbon as an efficient and durable bifunctional electrocatalyst for rechargeable Zn-air batteries.

Porous Transition Metal-Based Nanostructures as Efficient Cathodes for Aluminum-air Batteries

Prussian blue analog-derived nickel iron phosphide-reduced graphene oxide hybrid as an efficient catalyst for overall water electrolysis.

Zinc–air batteries (ZABs) have several advantages, including high energy density, cheap price and stable performances with good application prospects in the field of power batteries. The charging and discharging reactions for the air cathode of ZABs are the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), respectively, which play an important role in the whole performance of ZAB. Due to the cost and limited reserves of highly active precious metal catalysts, it is crucial to design alternative efficient and stable dual-functional non-precious metal catalysts. In the present review, we present a systematic summary of the recent progress in the use of transition metal-based electrocatalysts as alternatives to precious metals for the positive poles of ZAB air. Combined with state-of-the-art in situ characterization technologies, a deep understanding of the catalytic mechanism of OER/ORR provided unique insights into the precise design of excellent synthetic non-precious metal catalysts from the perspective of atomic structure. This review further shows that the hybrid electric battery is a new strategy to improve the efficiency of the hybrid electric battery, which could be available to alleviate the problem of resource shortage. Finally, the challenges and research trends for the future development of ZABs were clearly proposed.

/pdf/research-progress-of-bifunctional-oxygen-reactive-1ftwf52n.pdf

Research Progress of Bifunctional Oxygen Reactive Electrocatalysts for Zinc–Air Batteries

A composite catalyst with a novel construction of bimetallic phosphide FeNiP nanoparticles embedded in an N,P double-doped carbon matrix was prepared. It was demonstrated to be a trifunctional catalyst that can efficiently catalyze the oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). It was found that the introduction of oleylamine during the preparation can adjust the catalytic sites and finally lead to ideal catalytic performances. The obtained catalyst exhibited efficient ORR catalytic performance that surpassed the commercial Pt/C catalyst, with the OER performance comparable to that of RuO2 as well as excellent HER performance. The ORR half-wave potential is 0.879 V (vs. RHE) in 0.1 M KOH solution, while the OER overpotential at a current density of 10 mA cm−2 is only 280 mV in 1 M KOH solution. The potential gap between the ORR and OER was only 0.700 V in 0.1 M KOH solution. This trifunctional catalyst was further evaluated in energy devices including zinc–air batteries and water electrolysis. The liquid zinc–air battery assembly achieved a power density of 169 mW cm−2 and stably undergoes charge–discharge cycles for 210 hours. The solid-state zinc–air battery achieved a power density of 70 mW cm−2 and stably undergoes charge–discharge cycles for 40 hours. These performances surpassed the batteries assembled with a Pt/C-RuO2 mixed catalyst. This work established a foundation of composite catalysts coupled with bimetallic phosphide and hybrid carbon substrates, which will promote the development of high-performance multifunctional catalysts and their application in energy devices.

FeNiP nanoparticle/N,P dual-doped carbon composite as a trifunctional catalyst towards high-performance zinc-air batteries and overall water electrolysis.

Wheat straw as carbon source to prepare FeCoP2 / N, P Dual-Doped carbon matrix as bifunctional catalyst for application in rechargeable Zinc-air and Aluminum-air batteries

Wenming Li

Papers

FeNiP nanoparticle/N,P dual-doped carbon composite as a trifunctional catalyst towards high-performance zinc-air batteries and overall water electrolysis.

Wheat straw as carbon source to prepare FeCoP2 / N, P Dual-Doped carbon matrix as bifunctional catalyst for application in rechargeable Zinc-air and Aluminum-air batteries