NiMn-Layered Double Hydroxide Porous Nanoarchitectures as a Bifunctional Material for Accelerated <i>p</i>-Nitrophenol Reduction and Freestanding Supercapacitor Electrodes
Vikas Sharma, Mohd Salleh Aman, Shobit Omar
Abstract
The prolonged reactions for phase and morphology stabilization remain an issue in layered double hydroxides (LDHs), for example, NiMn LDH. The present work proposes a rational strategy for tuning the interfacial surface chemistry in the NiMn LDH phase to obtain grassy-mat-like porous nanoarchitectures. The approach gifts a morphology possessing a high specific surface area available for the ions’ adsorption and desorption, thereby enhancing the extent of reversible reactions. The porous nanoarchitecture displays excellent catalytic activity by reducing p-nitrophenol in just ∼300 s with a rate constant of 0.231 min–1 at a 2 mg mL–1 concentration. Alongside, as a freestanding binder-free supercapacitor electrode, the material delivers a high specific capacitance of ∼568 F g–1 at 1 mA cm–2, which is highest among all NiMn LDH variants prepared at different reaction times. The fabricated symmetric supercapacitor exhibits an excellent energy and a power density of ∼22 W h kg–1 at 1 mA cm–2 and ∼6429 W kg–1 at 10 mA cm–2, respectively. The device retains ∼83% capacitance, at 10 mA cm–2, after 5000 charge–discharge cycles. To the best of our knowledge, this is the first report where NiMn LDH is optimized in a shorter duration and proposed as a competitive bifunctional material for heterogeneous catalysis and supercapacitors.