Interfacial Covalent Bonds Regulated Electron‐Deficient 2D Black Phosphorus for Electrocatalytic Oxygen Reactions

Abstract

Developing resource‐abundant and sustainable metal‐free bifunctional oxygen electrocatalysts is essential for the practical application of zinc–air batteries (ZABs). 2D black phosphorus (BP) with fully exposed atoms and active lone pair electrons can be promising for oxygen electrocatalysts, which, however, suffers from low catalytic activity and poor electrochemical stability. Herein, guided by density functional theory (DFT) calculations, an efficient metal‐free electrocatalyst is demonstrated via covalently bonding BP nanosheets with graphitic carbon nitride (denoted BP‐CN‐c). The polarized PN covalent bonds in BP‐CN‐c can efficiently regulate the electron transfer from BP to graphitic carbon nitride and significantly promote the OOH* adsorption on phosphorus atoms. Impressively, the oxygen evolution reaction performance of BP‐CN‐c (overpotential of 350 mV at 10 mA cm−2, 90% retention after 10 h operation) represents the state‐of‐the‐art among the reported BP‐based metal‐free catalysts. Additionally, BP‐CN‐c exhibits a small half‐wave overpotential of 390 mV for oxygen reduction reaction, representing the first bifunctional BP‐based metal‐free oxygen catalyst. Moreover, ZABs are assembled incorporating BP‐CN‐c cathodes, delivering a substantially higher peak power density (168.3 mW cm−2) than the Pt/C+RuO2‐based ZABs (101.3 mW cm−2). The acquired insights into interfacial covalent bonds pave the way for the rational design of new and affordable metal‐free catalysts.

Surface‐Dependent Intermediate Adsorption Modulation on Iridium‐Modified Black Phosphorus Electrocatalysts for Efficient pH‐Universal Water Splitting

“…[51,52] After modified by metallic Ir species, it is clearly identified that the first peak in BPIr_sur (A") and BPIr_be catalysts (A") become less obvious and the second peaks (B" and B") shift toward low energies, suggesting the partial suppression on the oxidation degree of the BP surfaces, accompanied by the possible formation of metalphosphorus bonds that are favorable for structural stability. [53,54] Then, a broad peak at ≈2167.0 eV clearly appears in Adv. Mater.…”

A Kinetically Superior Rechargeable Zinc‐Air Battery Derived from Efficient Electroseparation of Zinc, Lead, and Copper in Concentrated Solutions

“…Rechargeable zinc-air batteries (ZABs) are widely considered as one of the most promising energy storage devices, owing to their high specific energy density (1084 Wh kg À 1 ), unique semi-closed systems, low cost, and environmentally friendly nature (Scheme 1). [39,40] There are two main avenues for the development of ZABs: electrochemical cells based on either aqueous alkaline or aprotic electrolytes. [41] For water-based electrolytes, their low energy efficiency is a fundamental problem.…”

“…Great progress has been made in the development of bifunctional electrocatalysts for these processes. [39,40,[42][43][44][45][46] Moreover, fundamental problems on the Zn anode side must be addressed. [47] Firstly, the corrosion of the Zn anode is a parasitic reaction, in which Zn reacts with water to produce zinc hydroxide (Zn(OH) 2 ) or, in alkaline solution, [Zn(OH) 4 ] 2À and hydrogen gas.…”

“…Rechargeable zinc‐air batteries (ZABs) are widely considered as one of the most promising energy storage devices, owing to their high specific energy density (1084 Wh kg −1 ), unique semi‐closed systems, low cost, and environmentally friendly nature (Scheme 1). [39,40] …”

“…On the cathode side of ZABs, the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) strongly influence the charge‐discharge kinetics and energy efficiency of ZABs. Great progress has been made in the development of bifunctional electrocatalysts for these processes [39,40,42–46] …”