NiMn-Layered Double Hydroxide Porous Nanoarchitectures as a Bifunctional Material for Accelerated p-Nitrophenol Reduction and Freestanding Supercapacitor Electrodes

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.

Mesoporous carbon-supported flower-like Mn-doped Ni–Co layered double hydroxides with high cycling capacitance retention for supercapacitors

“…8(h), the energy density of the ASC device is 23.68 W h kg −1 at 325 W kg −1 and 6.4 W h kg −1 at 8550 W kg −1 . 36,44,49,[61][62][63][72][73][74][75][76] Furthermore, a red LED was successfully lit up by two ASC devices as shown in Fig. 8(i), confirming the feasibility of the ASC and showing the potential of SAC@NiCoMn-LDH in cathode material applications.…”

Manganese–cobalt hydroxide nanosheets anchored on a hollow sulfur-doped bimetallic MOF for high-performance supercapacitors and the hydrogen evolution reaction in alkaline media

“…The power-law relationship between scan rate v and current i can be calculated using the following equations to qualitatively examine the capacitive and diffusion-controlled effects present in the S-MnCo-MOF-74@MnCo LDH electrode. 62 i = aν b log i = b log( ν ) + log( a )…”

“…The power-law relationship between scan rate v and current i can be calculated using the following equations to qualitatively examine the capacitive and diffusion-controlled effects present in the S-MnCo-MOF-74@MnCo LDH electrode. 62 i ¼ aν b log i ¼ b logðνÞ þ logðaÞ a and b are adjustable parameters. b equals 0.5 for a diffusion-controlled process and 1 for a capacitive process.…”

Efficient improvement in the electrochemical performance of petal-like lamellar NiMn–LDHs with affluent oxygen vacancies derived from Mn MOF-74

“…5a), which should be attributed to 530.8 eV O 2− , 531.6 eV OH − and 532.9 eV at adsorbed water with good consistency between NiMn-LDH 3 and O-LDH samples about binding energy positions and shapes. 50 The intensity values of specific peaks assigned to different elements are listed in Tables S1-S3, † in which a high content of OH − (52.76% and 37,38 The binding energies of Ni 2p 3/2 in NiMn-LDH 3 and O-LDH samples were found to be 856.6 eV, 858.7 eV and 862.7 eV, which are attributed to Ni 2+ , Ni 3+ and satellite peaks, respectively. 37,38,46a,48a Similarly, Ni 2+ , Ni 3+ and satellite peaks derived from Ni 2p 1/2 can be seen in NiMn-LDH 3 and O-LDH samples with binding energies of 856.6 eV, 858.7 eV and 862.7 eV.…”