Self‐Supported Oxygen and Molybdenum Dual‐Doped Cobalt Phosphide Hierarchical Nanomaterials as Superior Bifunctional Electrocatalysts for Overall Water Splitting

Abstract

Electrocatalytic water splitting is considered an attractive way to achieve clean and sustainable energy production. Herein, a series of self‐supported oxygen and molybdenum dual‐doped cobalt phosphides grown on Ni foam (O,Mo−CoP/NFs) were prepared. The O,Mo−CoP/NFs exhibited 3D hierarchical morphologies including urchin‐like nanostructures assembled with nanorods and nanoflowers assembled with ultrathin nanosheets. The optimized O,Mo−CoP/NFs‐2 nanoflowers exhibited superior electrocatalytic performance for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with an overpotential of only 59 mV at 10 mA cm−2 for HER and 301 mV overpotential at 100 mA cm−2 for OER. Moreover, the O,Mo−CoP/NFs‐2 nanoflowers exhibited efficient overall water splitting as low as 1.66 V for 100 mA cm−2 with outstanding long‐term stability, even superior to the commercial Pt−C/NF and RuO2/NF system. The superior activity of self‐supported O,Mo−CoP/NFs‐2 nanoflowers was attributed to the synergistic effect of O and Mo dual doping, which promoted its intrinsic catalytic activity, and its particular morphology of self‐supported 3D hierarchical nanoflowers, which could expose more catalytic sites and enable facile gas escape. Moreover, the device of overall water splitting can be powered by a single AA battery or a 1.5 V solar cell, showing its great potential for practical applications.

Enhanced hydrogen evolution activities of the hollow surface‐oxidized cobalt phosphide nanofiber electrocatalysts in alkaline media

“…All peaks of cobalt phosphide almost vanished in the alkaline electrolyte, and peaks were only observed at 492 and 601 cm −1 , which are attributed to the CoOOH or Co‐O stretching modes, respectively 7,35 . When a higher voltage (−0.4 V) was applied, the intensities of the peaks of CoP‐O considerably increased; in contrast, those of the peaks of CoP‐5 h negligibly changed compared with that at 0 V. The surface of CoP‐O can be more easily oxidized to CoOOH compared with CoP‐5 h due to its higher oxygen content, which can reduce the thermodynamic and kinetic barriers of hydroxylation 46,47 . The reasons for the exceptional HER activity, particularly in alkaline media, is as follows.…”

Iron and Oxygen Codoped Cobalt Phosphide Solvothermally Prepared from a Metal–Organic Framework for Oxygen Evolution

“…The S12). 50 Also, the EDX result on O− Co 0.58 Fe 0.42 P y shows Co, Fe, P, and O peaks (Figure S8). These indicate that oxygen is also doped into the structure and that the prepared nanoparticles are phosphides in nature.…”

“…The XPS deconvoluted O 1s region spectra of the O–Co 0.58 Fe 0.42 P y show that the peak originated from the Co–O–P structure (Figure S12). Also, the EDX result on O–Co 0.58 Fe 0.42 P y shows Co, Fe, P, and O peaks (Figure S8). These indicate that oxygen is also doped into the structure and that the prepared nanoparticles are phosphides in nature.…”

Theoretical Study of Hydrogen Production from Ammonia Borane Catalyzed by Metal and Non-Metal Diatom-Doped Cobalt Phosphide

“…The dehydrogenation of NH 3 BH 3 catalyzed by Co and Cu diatom-doped magnesium oxide is better than that of Co- and Cu-doped magnesium oxide alone [ 45 ]. The catalytic performance and efficiency of O and Mo diatom-doped cobalt phosphide lamellar nanomaterials as catalysts for water cracking has been significantly improved [ 46 ].…”