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Self-reconstruction of catalysts during oxygen evolution reaction (OER) is crucial for the development of energy conversion technologies. However, the relationship between the specific atomic structure of pre-catalysts and their electrocatalytic behavior after reconstruction via dual-ion leaching has not been extensively researched. In this work, we design a highly effective non-noble metal OER catalyst with heterointerface through continuous self-reconstruction of Co2(OH)3Cl@NiMoO4 as pre-catalyst by a straightforward dual-ion (i.e. MoO42− and Cl−) leaching. In-situ Raman and in-situ Fourier transform infrared (FT-IR) spectroscopy have precisely identified the progressive phase transformation of the pre-catalyst during self-reconstruction, which results in a stable heterojunction of CoOOH and NiOOH (CoOOH@NiOOH). Further calculations based on density functional theory (DFT) of CoOOH@NiOOH evident that more electrons will be aggregated in the Fermi level of Co. Notably, Gibbs free energy (ΔG) for different OER steps of CoOOH@NiOOH exhibit lower energy costs of all intermediates, implying the well catalytic properties. Ultimately, the catalyst derived from dual-ion leaching displays outstanding OER performance, characterized by an overpotential of 275 mV at a current density of 10 mA·cm−2 and exceptional stability over 12 h reaction. This work successfully paves a way of finding high-performance OER catalysts based on non-noble metal through dual-ion leaching during self-reconstruction. [ABSTRACT FROM AUTHOR]

Heteroatom doping is one of the most promising strategies toward regulating intrinsically sluggish electronic conductivity and kinetic reaction of transition metal oxides for enhancing their lithium storage. Herein, we designed phosphorus-doped NiMoO4 nanorods (P-NiMoO4) by using a facile hydrothermal method and subsequent low-temperature phosphorization treatment. Phosphorus doping played an indispensable role in significantly improving electronic conductivity and the Li+ diffusion kinetics of NiMoO4 materials. Experimental investigation and density functional theory calculation demonstrated that phosphorus doping can expand the interplanar spacing and alter electronic structures of NiMoO4 nanorods. Meanwhile, the introduced phosphorus dopant can generate some oxygen vacancies on the surface of NiMoO4, which can accelerate Li+ diffusion kinetics and provide more active site for lithium storage. As excepted, P-NiMoO4 electrode delivered a high specific capacity (1,130 mAh·g−1 at 100 mA·g−1 after 100 cycles), outstanding cycling durability (945 mAh·g−1 at 500 mA·g−1 over 200 cycles), and impressive rate performance (640 mAh·g−1 at 2,000 mA·g−1) for lithium ion batteries (LIBs). This work could provide a potential strategy for improving intrinsic conductivity of transition metal oxides as high-performance anodes for LIBs. [ABSTRACT FROM AUTHOR]

NiMoO4 has attracted intensive attention as one of the promising ternary metal oxides because of its high specific capacitance and electrical conductivity compared to traditional transition-metal oxides. In this study, NiMoO4 nanorods uniformly decorated on graphene nanosheets (G-NiMoO4) are synthesized through a facile hydrothermal method. The prepared G-NiMoO4 composite exhibits a high specific capacitance of 714 C·g−1 at 1 A·g−1 and an excellent rate capability, with a retention ratio of 57.7% even at 100 A·g−1. An asymmetric supercapacitor (ASC) fabricated with the G-NiMoO4 composite as the positive electrode and Fe2O3 quantum dot-decorated graphene (G-Fe2O3-QDs) as the negative electrode delivers an ultrahigh energy density of 130 Wh·kg−1, which is comparable to those of previously reported aqueous NiMoO4-based ASCs. Even when the power density reaches 33.6 kW·kg−1, an energy density of 56 Wh·kg−1 can be maintained. The ASC device exhibits outstanding cycling stability, with a capacitance retention of 113% after 40,000 cycles. These results indicate that the G-NiMoO4 composite is a promising candidate for ASCs with ultrahigh energy density and excellent cycling stability. Moreover, the present work provides an exciting guideline for the future design of high-performance supercapacitors for industrial and consumer applications via the simultaneous use of various pseudocapacitive materials with suitable potential windows as the positive and negative electrodes. [ABSTRACT FROM AUTHOR]