A Low‐Cost, Durable Bifunctional Electrocatalyst Containing Atomic Co and Pt Species for Flow Alkali‐Al/Acid Hybrid Fuel Cell and Zn–Air Battery

Abstract

Transition metal single atoms anchored on nitrogen‐doped carbon (M‐N‐C) matrix with M‐N‐C active sites have shown to be promising catalysts for both hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). Herein, a hybrid catalyst with low‐level loading of atomic Pt and Co species encapsulated in nitrogen‐doped graphene (Pt@CoN4‐G) is developed. The Pt@CoN4‐G shows low overpotential for HER in wide‐pH electrolyte and manifests improved mass activity with almost eight times greater than that of Pt/C at an overpotential of 50 mV. The Pt@CoN4‐G also exhibits a top‐level ORR activity (half‐wave potential, E1/2 = 0.893 V) and robust stability (>200 h) in alkaline medium. Using theoretical calculations and comprehensive characterizations , the strong metal–support interactions between Pt species and CoN4‐G support and synergistical cooperation of multiple active sites are clarified. A flow alkali‐Al/acid hybrid fuel cell using Pt@CoN4‐G as cathode catalyst delivers a large power density of 222 mW cm−2 with excellent stability to achieve simultaneously hydrogen evolution and electricity generation. In addition, Pt@CoN4‐G endows a flow Zn‐air battery with high power density (316 mW cm−2), good stability under large current density (>100 h at 100 mA cm−2), and long cycle life (over 600 h at 5 mA cm−2).

Water electrolysis for hydrogen production: from hybrid systems to self-powered/catalyzed devices

“…7d). Benefiting from these advantages of the BPM compared to conventional AEM and PEM, the BPM has been widely used in various systems for hydrogen production, such as photoelectrochemical water splitting, 142,143 electrochemical water splitting, 144,145 hybrid water splitting, 146,147 alkali–acid hydrazine fuel cell, 148–150 and zinc–H 2 batteries. 151 Nonetheless, it is worth noting that the electrochemical resistance is directly influenced by the distance between two electrodes.…”

Anion-hosting cathodes for current and late-stage dual-ion batteries

“…Current researches are focusing on exploring novel and low-cost cathode/anode materials based on lithium-ion batteries (LIBs) [7,8] and post-LIBs (sodium-, potassium-, calcium-, magnesium-, and alumi-num-ion batteries) [9,10]. Furthermore, novel energy storage concepts have also been studied to develop energy storage devices (ESDs) that have low-carbon, environmentalfriendliness, and exceptional performance [11][12][13][14].…”

Ultra-thin carbon layer encapsulated NiCoP coralline-like catalysts for efficient overall water electrolysis

“…[4][5][6] Commercially, employing earth-abundant inexpensive elements as noble-metal alternatives for water electrolysis is greatly signicant and considered a major innovation. [7][8][9] The use of bifunctional catalysts has also become one of the most intriguing options for more reduction of catalyst costs. 10 NiCo-based bimetallic phosphides as bifunctional catalysts have attracted broad attention, which is because the synergy of different metal atoms results in redistribution of electrons and promotes the improvement of catalytic activity for water electrolysis.…”

“…4–6 Commercially, employing earth-abundant inexpensive elements as noble-metal alternatives for water electrolysis is greatly significant and considered a major innovation. 7–9 The use of bifunctional catalysts has also become one of the most intriguing options for more reduction of catalyst costs. 10…”