Au/Ni12P5 core/shell nanocrystals from bimetallic heterostructures: in situ synthesis, evolution and supercapacitor properties

Abstract

A synthetic route to achieve core/shell nanostructures consisting of noble metal cores and single crystal semiconductor shells with different crystal systems is proposed, which involves a simple phosphorization process from corresponding bimetallic heterostructures. The triphenylphosphine is designed to serve as both a capping agent and a phosphorous source during the formation of Au/Ni 12 P 5 core/shell nanoparticles (NPs) from Au-Ni bimetallic heterodimers. The semiconductor shells of the obtained Au/Ni 12 P 5 nanostructures are controlled to form single crystals with a thickness of B5 nm. The structure-dependent supercapacitor properties of Au-modified Ni 12 P 5 nanostructures were further investigated. The synergistic effect of the metal/semiconductor nanostructure is observed to be superior to its oligomer-like counterpart when serving as a supercapacitor electrode. The specific capacitance of an electrode fabricated from core/shell NPs is 806.1 F g À1 with a retention of 91.1% after 500 charge-discharge cycles.

Rich‐Mixed‐Valence NixCo3−xPy Porous Nanowires Interwelded Junction‐Free 3D Network Architectures for Ultrahigh Areal Energy Density Supercapacitors

“…Owing to the similar nanostructure, both NiCoP‐CoP PNWCHAs and NiCo 2 S 4 nanotube‐woven nanostructures (62% capacitance retention from 1 to 20 A g −1 ) have high rate capability. Especially, the rate capability of our NiCoP‐CoP is superior to that of recently reported electrodes based on other transition‐metal phosphides nanostructures and composites at a similarly 10 times higher current density (Table S2, Supporting Information) …”

“…In particular, the C g is also much higher than those of recently reported phosphides nanostructures and composites (data are listed in Table S2, Supporting Information). The C g = 1969 F g −1 is roughly six times of that for Cu 3 P nanocrystals (332 F g −1 at 0.5 A g −1 ), two times of that for Ni 12 P 5 nanocapsules (949 F g −1 at 1 A g −1 ) and that for mesoporous Ni 2 P nanobelts (1074 F g −1 at 0.6 A g −1 ), and higher than twice of other transition‐metal phosphides based composites such as Ni 2 P‐Ni 5 P 4 particles (843 F g −1 at 1 A g −1 ), rGO/Ni 2 P (890 F g −1 at 1 A g −1 ), Au/Ni 12 P 5 (806 F g −1 at 0.2 A g −1 ), Ni x Co 1− x O/Ni y Co 2− y P@C (820 F g −1 at 1 A g −1 ) . Even at 20 A g −1 , a specific capacitance corresponds to 68% of the value at 1 A g −1 , can still be obtained, thus showing the exceptional rate capability.…”

Metal Phosphides and Phosphates‐based Electrodes for Electrochemical Supercapacitors

“…[47] In another example, Ni 12 P 5 nanoparticles (NPs) were developed, where TPP was also used as the phosphorus source. [76] Besides the examples mentioned above, MPs can be synthesized by certain direct-growth strategies, such as electrochemical deposition. In the electrochemical deposition, the desired MPs are deposited onto the surface of a conductive substrate by electrolysis of a solution precursor containing the desired metal ion or its chemical complex.…”

“…Taking Co 2 P as an example, Co 2 P nanostructures with both rod‐like and flower‐like morphologies have been synthesized by decomposition of Co(acac) 3 in OAm (oleylamine) and TPP (triphenylphosphine), where TPP is used as the phosphorus source . In another example, Ni 12 P 5 nanoparticles (NPs) were developed, where TPP was also used as the phosphorus source …”

An Approach to Preparing Ni–P with Different Phases for Use as Supercapacitor Electrode Materials

“…In their work, pure Ni 12 P 5 was successfully synthesized and investigated as a supercapacitor electrode material. However, the tedious and toxic preparation process, low specific capacitance (806.1 F g −1 at 0.2 A g −1 ) and poor cycle stability (a retention of about 80 % after 500 charge–discharge cycles) made it difficult to meet the demands of practical applications 37. Therefore, one would expect nickel phosphide to be a promising candidate for high‐performance pseudocapacitor electrode materials.…”