Alkaline Water Electrolysis by NiZn-Double Hydroxide-Derived Porous Nickel Selenide-Nitrogen-Doped Graphene Composite

Abstract

The large-scale application of water electrolysis for the generation of hydrogen can be made viable only by the development of inexpensive, robust, and bifunctional electrocatalysts. Here, we report a self-templating method for the design of porous, edge-site-rich hybrid nanomaterials via the selective etching of layered double hydroxide precursors that contain an amphoteric metal by alkali treatment, followed by vapor phase selenization. The obtained hexagonal nickel selenide nanoplates anchored over nitrogen-doped graphene showed highly efficient and robust oxygen evolution reaction (OER) electrocatalysis due to the inherent in situ electrochemical oxidation property of selenides demonstrating low overpotential of 311 mV to achieve the 10 mA cm −2 water oxidation current density in 1 M KOH. The faster reaction kinetics and long-term stability of the catalyst encouraged us to demonstrate a real alkaline water electrolyzer, which enables high-performing overall water splitting with a low overpotential of 460 mV from theoretical potential of 1.23 V to generate sufficient amounts of H 2 and O 2 by achieving a current density of 10 mA cm −2 . This study thus provides a valuable strategy to tailor the surface texture of the catalyst as well as its effectiveness in developing robust multifunctional electrocatalysts, promoting the efficient design of porous materials for catalytic applications.

A NiFe layered double hydroxide-decorated N-doped entangled-graphene framework: a robust water oxidation electrocatalyst

“…However, the O 1s peak is found to intensify aer the NiFe-LDH loading, basically coming from the hydroxide moieties as well as intercalated carbonate and water species. [40][41][42] Furthermore, by high-resolution XPS, the NEGF and NiFe-LDH/NEGF are comparatively analyzed in the C 1s, N 1s, and O 1s core regions. Various chemical states of carbon, i.e., C-C, C]C (284), C-O (286), and C-N/C]N (400), with different binding energy values owing to the unique chemical environment of carbon are marked in the respective gures ( Fig.…”

Direct Regulation of Double Cation Defects at the A1A2 Site for a High-Performance Oxygen Evolution Reaction Perovskite Catalyst

“…As presented in Figure 5, C dl of A-LSCF10 (0.47 mF) and A-BSCF10 (0.34 mF) is ∼5.2 times and ∼4.8 times as high as A-LSCF0 (0.09 mF) and A-BSCF0 (0.07 mF), respectively. According to the calculating methods of the ECSA reported in the literature, 53 ECSAs of A-LSCF10 and A-BSCF10 are 11.75 and 8.5 cm −2 , respectively. 53 Subsequently, by normalizing the measured current relative to its ECSA, the intrinsic activity of A-LSCF and A-BSCF perovskites (j ECSA , Figure S15) was further compared.…”

“…According to the calculating methods of the ECSA reported in the literature, 53 ECSAs of A-LSCF10 and A-BSCF10 are 11.75 and 8.5 cm −2 , respectively. 53 Subsequently, by normalizing the measured current relative to its ECSA, the intrinsic activity of A-LSCF and A-BSCF perovskites (j ECSA , Figure S15) was further compared. The results show that their internal activity follows the same trend as a geometric activity.…”

Porous Co9S8 Nanosheet Arrays@Co Foam Electrode via in Situ Sulfidation at Room Temperature for Superior Supercapacitors

“…In order to understand the improved electrochemical performance of the CHP@CS-48 electrode, the electrochemical active surface areas (ECSA) of all the electrodes are estimated (eq S1 and S2). 48,49 As shown in Table S1, the CHP@CS-48 electrode has the largest electrochemical active surface area (70.75 cm 2 ), which is much larger than those of the other electrodes (CHP, 45.75; CHP@CS-6, 48.5; CHP@CS-24, 50.75; CHP@CS-72, 52.0 cm 2 ), i.e., CHP@CS-48 is superior to other electrodes. Figure 7d shows the CV curves of CHP@CS-48; it can be clearly seen that all the CV curves have a pair of well-defined peaks, corresponding to the following redox reaction of Co 9 S 8 in KOH electrolyte 50 Co S 9OH Co S (OH) 9e This unique redox characteristic indicates that the capacitance is mainly derived from the Faradaic pseudocapacitance.…”