The novel mushroom-like carbon nanotube top-supported FeNi alloy doped P material with ultra-high activity for OER/HER/ORR

The development of efficient and low-cost alternatives to precious metals as electrocatalysts for electrochemical oxygen evolution (OER), hydrogen evolution (HER) and oxygen reduction (ORR) reactions is an urgent task to solve the current resource shortage problem. Here, we designed a novel enoki shaped catalyst in which FeNi alloy was grown and P was doped on the top of carbon nanotubes (EM-FeNiP@HCNT). The positive repulsion effect between PDDA and Fe2+Ni2+ made FeNi alloy oriented to grow on the top of the carbon nanotubes. C18-L-Glu and pyrrole were used as template and carbon source, respectively. After high temperature calcination, C18-L-Glu surfactant template was removed, the hollow nanotube structure was formed, the N element was doped and the FeNi ion was reduced to FeNi alloy by one step. EM-FeNiP@HCNT provides superior HER/OER/ORR performance owing to its specific morphology, porous structure, doped P and the synergistic effect between FeNi alloy and P. The prepared EM-FeNiP@HCNT is capable of driving 10 mA cm−2 at 294 (OER) and −224 mV (HER), respectively. The initial and half-wave potential in the ORR reaction require only 0.90 V and 0.78 V. Moreover, the number of transferred electrons of EM-FeNiP@HCNT in the ORR reaction reaches 3.89. The synergistic effect between FeNi and P atom doped carbon substrates provides high electrocatalytic activity and high stability for HER, OER and ORR, which is comparable to or better than that of commercial RuO2 or Pt/C catalysts. Meanwhile, density functional theory (DFT) calculation shows the composite has low adsorption energy (0.80 V, HER; −2.21 eV, OER/ORR). Therefore, the prepared EM-FeNiP@HCNT shows great application potential as a three-function electrocatalyst.