Ultrathin NiFe-Based Nanosheet Electrocatalysts for Efficient Water Oxidation

Abstract

Exploiting highly active, low cost, and stable electrocatalysts for overall water splitting is the central issue for conquering the energy crises and environmental pollution. Herein, an element-incorporation strategy is proposed to synthesize NiFe-based (oxy)hydroxide and selenide nanosheets anchored on a stainless steel mesh (SSM). The (Ni,Fe)OOH/SSM (D-Ni 2 Fe 1 /SSM) obtained via sputtering, alloying, and dealloying strategies and (Ni,Fe)Se 2 (S−Ni 2 Fe 1 /SSM-450) sintering at 450 °C based on the D-Ni 2 Fe 1 /SSM exhibit outstanding hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities in 1 M KOH, respectively. The preparation of precursor bimetallic hybrid films via sputtering is vital for the subsequent regulation of electronic structures near the active sites between Ni and Fe atoms. D-Ni 2 Fe 1 /SSM requires 176 mV to reach 10 mA cm −2 for the HER, whereas 194 mV is needed for S−Ni 2 Fe 1 /SSM-450 to reach 10 mA cm −2 for the OER. Additionally, these two electrodes are assembled into an alkaline electrolyzer for overall water splitting with a cell voltage of 1.64 V at 10 mA cm −2 and exhibit outstanding stability. The unique roughened nanosheet morphology, large electrochemical surface area, and optimized electronic structures are responsible for the outstanding HER/OER performances.

S-Doped Ni0.5Co0.5Fe2O4 Porous Single-Crystalline Nanosheets for Electrocatalytic Oxygen Evolution

“…Current research focuses on non-precious metal compounds, such as Fe, Ni, Co, and Mn-based oxides, sulfides, and hydroxides. − Some of these compounds are indeed prospective catalysts to activate OER. For instance, Co- and Fe-based oxides are stable in alkaline media; their OER properties are not so much different from those of Ru and Ir oxides. , In particular, spinel type oxides (general formula AB 2 O 4 ) have been accepted as promising OER catalysts owing to their multiple valence of cations and their ability to transform between different oxidation states. − Among spinel oxide structures, spinel ferrite (MFe 2 O 4 , M = Co, Ni, Mn, etc.)…”

M2+-Doped Nickel Selenide Nanoflowers (M = Co, Cu, and Zn) for Supercapacitors

“…New energy storage devices with high energy/power density, including supercapacitors (SCs) and lithium metal batteries (LMBs), have obtained increasing interest for the fast development of electric vehicles. − Transition-metal selenides (TMSes) have aroused much attention due to their unique optical and electronic properties, making them potential materials for applications in SCs, photocatalysis, and electrocatalysis. − Metal–Se bond is weaker than metal–O and metal–S bonds, which is kinetically favored over the conversion reaction; moreover, TMSes possess a special d -electronic structure and adjustable coordination environment. , Hence, TMSes are more suitable as electrode materials for SCs compared with transition-metal oxides/sulfides. Additionally, the electronic conductivity of half-metallic Se is larger than that of nonmetallic S (1 × 10 –5 vs 5 × 10 –28 S m –1 ); therefore, TMSes have gained tremendous attention in the field of SCs .…”

Construction of a Zn0.65Cd0.35S/SnO2 S-scheme heterojunction for efficient photocatalytic CO2 reduction

“…Yu et al created an S-scheme conduction mechanism in 2019. 8 Recently, several S-scheme heterostructures, such as Cs 3 Bi 2 Br 9 /Bi 2 WO 6 , 9 LaNiO 3 /CdLa 2 S 4 , 10 and g-C 3 N 4 /CDs/WO 3 , have been constructed, 11 indicating that the S-scheme heterostructure system has a strong reduction ability and high separation efficiency of charge carriers, thus improving the photocatalytic activity. 12,13…”