Engineering Interfacial Built‐in Electric Field in Polymetallic Phosphide Heterostructures for Superior Supercapacitors and Electrocatalytic Hydrogen Evolution

Abstract

Herein, a patterned rod‐like CoP@NiCoP core‐shell heterostructure is designed to consist of CoP nanowires cross‐linked with NiCoP nanosheets in tight strings. The interfacial interaction within the heterojunction between the two components generates a built‐in electric field that adjusts the interfacial charge state and create more active sites, accelerating the charge transfer and improving supercapacitor and electrocatalytic performance. The unique core‐shell structure suppresses the volume expansion during charging and discharging, achieving excellent stability. As a result, CoP@NiCoP exhibits a high specific capacitance of 2.9 F cm−2 at a current density of 3 mA cm−2 and a high ion diffusion rate (Dion is 2.95 × 10−14 cm2 s−1) during charging/discharging. The assembled asymmetric supercapacitor CoP@NiCoP//AC exhibits a high energy density of 42.2 Wh kg−1 at a power density of 126.5 W kg−1 and excellent stability with a capacitance retention rate of 83.8% after 10 000 cycles. Furthermore, the modulated effect induced by the interfacial interaction also endows the self‐supported electrode with excellent electrocatalytic HER performance with an overpotential of 71 mV at 10 mA cm−2. This research may provide a new perspective on the generation of built‐in electric field through the rational design of heterogeneous structures for improving the electrochemical and electrocatalytical performance.

A Se-induced heterostructure electrode with polymetallic-CoNiFe towards high performance supercapacitors

“…Besides, the selenized CoNiFe-Se heterojunction generates a built-in electric field that shows a strong interface effect, exposing more active site surfaces, accelerating charge transfer, thus improving the performance of SCs. 48…”

Crucial Role of Metal Coordination Number in Optimizing Electrocatalyst Activity of Holey Large-Area 2D Ru Nanosheets

“…The benefits of the holey nanosheet morphology on the charge transfer properties of Ru metal were supported by electrochemical impedance analysis (EIS). In Figure e, all holey Ru metal nanosheets exhibited much smaller semicircles in Nyquist plots compared to bulk Ru metal, indicating reduced charge transfer resistance ( R ct ) . Among the present nanosheet materials, Ru NS-200 demonstrated the smallest R ct value, affirming that calcination at 200 °C represents the optimal heating condition for improving the interfacial charge transfer properties.…”

“…The enhanced contribution of the Volmer–Tafel mechanism in the optimal metal coordination number primarily accounted for the improved HER activity of locally structured-optimized Ru metal nanosheets. Given the extensive library of exfoliated 2D nanosheets of metal oxides and metal chalcogenides, ,,, this phase transition route offers valuable opportunities to explore highly anisotropic metal nanosheets. Our current focus lies in applying this methodology to metal nanosheet-based nanocomposites with promising energy-functional materials.…”

Electronic Structure Regulated Nickel-Cobalt Bimetal Phosphide Nanoneedles for Efficient Overall Water Splitting

“…There are characteristic peaks of phosphate and pho phide in P 2p narrow scan spectrum. The peak at the lower binding energy of ~129.5 e could be assigned to P 2p1/2 and P 2p3/2 of phosphide, respectively, whereas the peaks ~132 eV could contribute to the P-O originated from the oxidation after exposure to t air [38]. The addition of Co induces a red shift in P 2p3/2 and a blue shift in Ni 2p3 XRD was used to determine the phases of the prepared materials.…”

“…The value of ECSA for each catalyst investigated in 1 M KOH for OER; Table S7: Comparison of overall water splitting performance with other reported electrocatalysts. References [34,37,38,[41][42][43][44][45]48,49,52,[55][56][57][58][59][60] are cited in the supplementary materials.…”