Magnetic metal phosphide nanorods as effective hydrogen-evolution electrocatalysts

Tunable and Specific Formation of C@NiCoP Peapods with Enhanced HER Activity and Lithium Storage Performance

“…As shown in Figure 5a,t he complete surveys of peapodlikeN iCoP@CNT nanocompositesr eveal the existence of Ni 2p, Co 2p, P2 p, and C1 s. The binding energies (BE)f or oxidized Ni (856.1 eV), Co (781.6 eV), and P(133.6 eV) are assigned to Ni 2 + ,C o 2 + ,a nd P 5 + species, respectively. [19,23,35] The 1-778.2 eV). [19,23,35] The two peaks at 130.4 and 129.6 eV agree wellw ithP2p 1/2 and P2 p 3/2 from NiCoP.T he results are consistentw ith the previous observations that the P2 pr egion of transition-metal phosphides usually splits into two peaks for P2 p 1/2 and P2 p 3/2 in high resolution XPS spectra.…”

“…[19,23,35] The 1-778.2 eV). [19,23,35] The two peaks at 130.4 and 129.6 eV agree wellw ithP2p 1/2 and P2 p 3/2 from NiCoP.T he results are consistentw ith the previous observations that the P2 pr egion of transition-metal phosphides usually splits into two peaks for P2 p 1/2 and P2 p 3/2 in high resolution XPS spectra. [19,21,35] Furthermore, the spectrum of P2 pa lso presentsapeak with ah igh BE of 133.6 eV,w hich could be attributed to PO 4 3À or P 2 O 5 caused by oxidationd ue to air contact.…”

“…Figure6as hows the HER polarization curves of differentc atalysts, among which the peapodlike C@NiCoP nanocomposites exhibit the smallest onset potential (h)o f 45 mV and achievec urrent densities of 10 and 50 mA cm À2 at an overpotential of 76 and 125 mV,r espectively.A se xpected, the peapodlike C@Ni 2 Pn anocomposite catalysts give the lowest activity,f ollowed by C@Ni 1.5 Co 0.5 Pa nd C@NiCoP,w hich is consistentw ith what has previously been reportedt hat pure Ni 2 Pn anorods are less active than the Ni 2 Pn anorods alloying with Co (Ni 0.67 Co 1.33 Pn anorods). [23] These overpotentials for C@NiCoPn anocomposites compare favorably with the behavior of other transition-metal-phosphides, Co-or Ni-based compounds,H ER catalysts in acidic solution like Co x P y ,N i x P y ,M oP, Mo 3 P, FeP 2 @C, FeP and nanosheets WP 2 SMPs,C oMoS 2 @OMC, Co 3 ZnC/RGO, ZnCoC, CoS 2 -RGO-CNT,a nd Co-NRCNTse tc. (Table S2,S upporting Information).…”

“…The resultss how the best HER catalyst is Co 2 P, followedby Co 1.33 Ni 0.67 P, and Ni 2 Pn anorods. [23] Thus, we may deducet hat the introduction of the Co elementi nN i 2 Pm ay promote the HER activity.U nfortunately, these nanorod samples tend to aggregate into relativelyl arger compactp ieces,w hich would causea na dverse impact on the electrocatalyst performance. Moreover,m ost of the conventional nanostructured NiCoP materials are SiO 2 -supported and were generally synthesized by temperature-programmed reduction( TPR) or solid-state metathesis, with other routes being seldom reported.…”

Synthesis of Co2P/graphene nanocomposites and their enhanced properties as anode materials for lithium ion batteries

“…Recently, our study has shown that Co 2 P is more active than Ni 2 P in electrochemical production reaction of H 2 [22]. Consequently, better lithium conversion properties which are concerning to reactions able to be promoted by catalysts are reasonably expected by using Co 2 P. Moreover, it has shown that owing to the large interfacial surface which allows more Li ions to diffuse into the nanomaterials, nanoparticles are usually more active in conversion reaction with lithium than their bulk counterpart, and their reversibility is also superior [17,23].…”