Integrated Energy Aerogel of N,S-rGO/WSe₂/NiFe-LDH for Both Energy Conversion and Storage

Abstract

High-performance active materials for energy-storage and energy-conversion applications require a novel class of electrodes: ones with a structure conducive to conductivity, large specific surface area, high porosity, and mechanical robustness. Herein, we report the design and fabrication of a new ternary hybrid aerogel. The process entails an in situ assembly of 2D WSe nanosheets and NiFe-LDH nanosheets on a 3D N,S-codoped graphene framework, accomplished by a facile hydrothermal method and electrostatic self-assembly technology. The obtained nanocomposite architecture maximizes synergistic effects among its three 2D-layer components. To assess the performance of this hybrid material, we deployed it as an advanced electrode in overall water splitting and in a supercapacitor. Results in both scenarios attest to its excellent electrochemical properties. Specifically, serving as a catalyst in an oxygen evolution reaction, our nanocomposite requires overpotentials of 1.48 and 1.59 V to obtain current densities of 10 and 100 mA cm, respectively. The hybrid material also efficiently electrocatalyzes hydrogen evolution reactions in base solution, necessitating overpotentials of -50 and -237 mV for current densities of 1.0 and 100 mA cm, respectively. The 3D hybrid, when applied to a symmetric supercapacitor device, achieves 125.6 F g capacitance at 1 A g current density. In summary, our study elucidates a new strategy to maximize efficiency via synergetic effects that is likely applicable to other 2D materials.

Recent Progress in Two‐Dimensional Layered Double Hydroxides and Their Derivatives for Supercapacitors

“…The delamination of nitrate intercalated LDH is more effective than that of chloride andc arbonatei ntercalated LDH, due to the weaker electrostatic intercalation of nitrate anions with cationsint he hostl ayers. [115] Additionally, somea nions with al arge size, such as dodecyl sulfate [116] and citrate, [117] can be intercalated into LDHs by means of one-step precipitation or anion-exchange methods, which can swell the interlayer spacing and causeaweakening of the interaction between the host layer and interlayer.S ubsequently,e asy delamination into 2D single layers with positive charges is assisted by an infinite solvation process. In severalc ases, formamide is used as the solvent for the exfoliation of LDHs.…”

“…Selenide has similar properties to those of the sulfides,s uch as high electrical conductivity.S ome studies on composites containing LDHs and selenides have been reported. [117,151] An N,S-rGO/WSe 2 /NiFe LDH composite was assembled from WSe 2 and NiFe LDH nanosheets on N,S-codoped G. [117] There is a close interfacial contact between the three 2D layered components of N,S-rGO, WSe 2 ,a nd NiFe LDH, which helps to stabilize the architecture during the charge/discharge process. Mean-while, ah ierarchically porous structure facilitates rapid ion/ electront ransfer and provides accessible active sites.…”

“…Selenide has similar properties to those of the sulfides, such as high electrical conductivity. Some studies on composites containing LDHs and selenides have been reported . An N,S‐rGO/WSe 2 /NiFe LDH composite was assembled from WSe 2 and NiFe LDH nanosheets on N,S‐codoped G .…”

Noble metal-free two dimensional carbon-based electrocatalysts for water splitting

“…Significant attempts have been exercised to develop 2D carbon-based hybrids, including 2D nanocarbons with transition metal compounds and metal-free g-C 3 N 4 for water splitting. The integration of transition metal compounds, such as transition metal sulfides, oxides, and phosphides or metal-free materials including g-C 3 N 4 and exfoliated black phosphorus (EBP) with carbon skeleton provides abundant catalytic active sites, while the carbon supports prevent the aggregation of transition metal compounds or metal-free substances, and provide high conductivity, which can enhance electrocatalytic activities of 2D carbon-based hybrids towards HER, OER, and overall water splitting [119][120][121][122][123][124][125][126][127].…”

Co2P Nanoparticles Wrapped in Amorphous Porous Carbon as an Efficient and Stable Catalyst for Water Oxidation

“…In recent years, plenty of transition-metal-based OER electrocatalysts have been reported because of their relatively high intrinsic activities and low cost, mainly including transition-metal oxides (Xu et al, 2016a ), oxyhydroxides (Smith et al, 2013 ; Friebel et al, 2015 ), selenides (Xu et al, 2017 ), and phosphides (Xu et al, 2016b ; Song et al, 2017 ; Ye et al, 2017 ; Hong et al, 2018 ; Zhang et al, 2018 ). Among these extensively researched electrocatalysts, transitional metal phosphides have attracted considerable attention (Gao et al, 2018 ).…”