Pseudocapacitive Ni‐Co‐Fe Hydroxides/N‐Doped Carbon Nanoplates‐Based Electrocatalyst for Efficient Oxygen Evolution

Abstract

The oxygen evolution reaction (OER) catalytic activity of a transition metal oxides/hydroxides based electrocatalyst is related to its pseudocapacitance at potentials lower than the OER standard potential. Thus, a well-defined pseudocapacitance could be a great supplement to boost OER. Herein, a highly pseudocapacitive Ni-Fe-Co hydroxides/N-doped carbon nanoplates (NiCoFe-NC)-based electrocatalyst is synthesized using a facile one-pot solvothermal approach. The NiCoFe-NC has a great pseudocapacitive performance with 1849 F g specific capacitance and 31.5 Wh kg energy density. This material also exhibits an excellent OER catalytic activity comparable to the benchmark RuO catalysts (an initiating overpotential of 160 mV and delivering 10 mA cm current density at 250 mV, with a Tafel slope of 31 mV dec ). The catalytic performance of the optimized NiCoFe-NC catalyst could keep 24 h. X-ray photoelectron spectroscopy, electrochemically active surface area, and other physicochemical and electrochemical analyses reveal that its great OER catalytic activity is ascribed to the Ni-Co hydroxides with modular 2-Dimensional layered structure, the synergistic interactions among the Fe(III) species and Ni, Co metal centers, and the improved hydrophily endowed by the incorporation of N-doped carbon hydrogel. This work might provide a useful and general strategy to design and synthesize high-performance metal (hydr)oxides OER electrocatalysts.

Natural‐Cellulose‐Nanofibril‐Tailored NiFe Nanoparticles for Efficient Oxygen Evolution Reaction

“…Notably, the XPS results implied that Fe species were constant, indicating there was no change for Fe species after OER measurement, which is contrast with Ni. However, previous literatures have proved that the Fe 3 + species can improve the OER activity of Ni-based catalyst by changing the electronic structure of Ni, [5,29] which is consistent with the XPS results of this work.…”

“…The Fourier transform infrared (FTIR) spectra at 3108 cm −1 of the NiFeNS and NiFeNSC corresponded to the stretching of NH 2 and/or OH groups (Figure f) . The band at 1131 cm −1 in the NiFeNSC spectrum was attributed to the C−N bonding .…”

“…[27,28] The Fourier transform infrared (FTIR) spectra at 3108 cm À 1 of the NiFeNS and NiFeNSC corresponded to the stretching of NH 2 and/or OH groups (Figure 2f). [5] The band at 1131 cm À 1 in the NiFeNSC spectrum was attributed to the CÀ N bonding. [16,29] For the OER process, it is the elementary step that water adsorption on the electrode surface.…”

“…Thus, efficient catalysts are desirable to decrease the overpotential and improve the OER activity. Although precious metal oxides, such as IrO 2 and RuO 2 , are the high‐performance OER catalysts, but their scarcity and high cost impede their practical applications . Therefore, designing highly active catalysts with low overpotentials and high efficiency toward the OER with abundant resources is greatly favorable …”

“…Although precious metal oxides, such as IrO 2 and RuO 2 , are the high-performance OER catalysts, but their scarcity and high cost impede their practical applications. [5] Therefore, designing highly active catalysts with low overpotentials and high efficiency toward the OER with abundant resources is greatly favorable. [4,6] Considerable efforts have therefore been devoted to developing non-precious metal catalysts for OER.…”