Cobalt Phosphides Nanocrystals Encapsulated by P‐Doped Carbon and Married with P‐Doped Graphene for Overall Water Splitting

Abstract

As one class of important functional materials, transition metal phosphides (TMPs) nanostructures show promising applications in catalysis and energy storage fields. Although great progress has been achieved, phase‐controlled synthesis of cobalt phosphides nanocrystals or related nanohybrids remains a challenge, and their use in overall water splitting (OWS) is not systematically studied. Herein, three kinds of cobalt phosphides nanocrystals encapsulated by P‐doped carbon (PC) and married with P‐doped graphene (PG) nanohybrids, including CoP@PC/PG, CoP‐Co2P@PC/PG, and Co2P@PC/PG, are obtained through controllable thermal conversion of presynthesized supramolecular gels that contain cobalt salt, phytic acid, and graphene oxides at proper temperature under Ar/H2 atmosphere. Among them, the mixed‐phase CoP‐Co2P@PC/PG nanohybrids manifest high electrocatalytic activity toward both hydrogen and oxygen evolution in alkaline media. Remarkably, using them as bifunctional catalysts, the fabricated CoP‐Co2P@PC/PG||CoP‐Co2P@PC/PG electrolyzer only needs a cell voltage of 1.567 V for driving OWS to reach the current density at 10 mA cm−2, superior to their pure‐phase counterparts and recently reported bifunctional catalysts based devices. Also, such a CoP‐Co2P@PC/PG||CoP‐Co2P@PC/PG device exhibits outstanding stability for OWS. This work may shed some light on optimizing TMPs nanostructures based on phase engineering, and promote their applications in OWS or other renewable energy options.

Earth‐Abundant Transition‐Metal‐Based Bifunctional Electrocatalysts for Overall Water Splitting in Alkaline Media

“…In addition, Yang et al. developed a two‐step strategy using the structural merits of supramolecular gels and a controllable thermal conversion technique for phase‐controlled synthesis of cobalt phosphide nanocrystals encapsulated by P‐doped carbon (PC) and married with P‐doped graphene (PG) . The electrolyzer using mixed‐phase CoP‐Co 2 P@PC/PG nanohybrids rather than pure‐phase counterparts on both the anode and cathode delivered a current density of 10 mA cm −2 at approximately 1.567 V. Additionally, the phase‐ and composition‐controlled synthesis of TMSs was reported, along with a systematic comparison of their catalytic properties for overall water splitting catalysis .…”

Phytic acid controlled in situ synthesis of amorphous cobalt phosphate/carbon composite as anode materials with a high mass loading for symmetrical supercapacitor: amorphization of the electrode to boost the energy density

“…At subsequent heating at a high temperature, the metal phytates decomposed into the respective metal phosphate along with freshly synthesized PA-derived carbons. 33,36 Typical SEM images of the a-PC@CoPi-CC8 show that the sample consisted of a PA-derived sheet-like structure (arrows) along with a layer of nanoparticles attached to the surface of the ber (Fig. 1A and B).…”

Cu,N‐Codoped Carbon Nanodisks with Biomimic Stomata‐Like Interconnected Hierarchical Porous Topology as Efficient Electrocatalyst for Oxygen Reduction Reaction

“…Moreover, to verify whether the Cu and N elements have been doped into the carbon matrix or not and distinguish their differences on surface electronic structures or elemental chemical states, the X‐ray photoelectron spectroscopy (XPS) tests for Cu‐N‐C‐ICHP NDs and Cu@Cu‐N‐C are also performed. Except for small O peak that may originate from the adsorbed O 2 or CO 2 in air, only the C, N, and Cu elements can be detected in the survey XPS spectra of those two samples ( Figure a). It should be mentioned that no characteristic Fe 2p signal peak can be found at the binding energy (BE) ranging from 700 to 740 eV, indicating that the etching by FeCl 3 and H 2 SO 4 does not introduce Fe impurity in the final Cu‐N‐C‐ICHP NDs sample (Figure S6, Supporting Information).…”