Coupling of Nd doping and oxygen-rich vacancy in CoMoO4@NiMoO4 nanoflowers toward advanced supercapacitors and photocatalytic degradation

Abstract

In this paper, we successfully prepared rare earth element-doped 0.8% Nd–CoMoO₄@NiMoO₄ nanoflowers with a large specific surface area using the sol–gel method for the first time. In the experiment, we added a structure-directing agent to successfully assemble the nanosheets into a three-dimensional ordered micro-flower shape. By using the strategy of forming a flower-shaped morphology with a structure-directing agent and doping Nd elements to generate oxygen vacancies, the problems of the collapse of the active material structure and slow reaction kinetics were solved. Through relevant electrochemical performance tests, it was found that when the rare earth element Nd was doped at a concentration of 0.8%, the material exhibited exceptional specific capacitance (2387 F g⁻¹ at 1 A g⁻¹) and cycling stability (99.3% after 10 000 cycles at 5 A g⁻¹). These performance characteristics far surpassed those of the other synthesized products. We assembled 0.8% Nd–CoMoO₄@NiMoO₄ with hydrophilic CNTs into an asymmetric device, 0.8% Nd–CoMoO₄@NiMoO₄//CNTs. This device exhibited high specific capacitance (262 F g⁻¹ at 1 A g⁻¹) and cycling stability (99.2% after 3000 cycles), with a good energy storage effect. In addition, 0.8% Nd–CoMoO₄@NiMoO₄ has a low band gap, which broadens the absorption range of the product and improves the utilization rate of visible light. The photocatalyst showed good degradation efficiency (all exceeding 96%) and cycling stability (96%) for all four dyes. This paper provides a new strategy and method for preparing doped polymetallic mixtures, which has potential application value.