ZIF-67-Derived (NiCo)S₂@NC Nanosheet Arrays Hybrid for Efficient Overall Water Splitting

Abstract

Electrocatalytic water splitting is considered a promising approach to obtain clean and sustainable hydrogen energy. The integration of optimal nanoarchitecture and multicomponent synergy has been a significant factor for designing a bifunctional electrocatalyst to promote the cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER). In particular, the charge migration, mass transfer, and gas release rate in the catalyzing process are closely correlated with the architecture of the catalyst. Here, ZIF-67-derived N-doped carbon nanofiber-supported (NiCo)­S2 nanosheet [(NiCo)­S2/NCNF] as a bifunctional electrocatalyst was synthesized using electrospinning, template etching, and subsequent gas sulfidation method. The hierarchical hybrid nanofiber with inner hollow cubes and outer nanosheets provides easy electron penetration, high charge/mass transportation efficiency, and robust structure stability. Furthermore, the MOF-derived carbon-encapsuled bimetal-sulfide and the synergistic effect of double active centers are conducive to an exceptional performance, showing low overpotentials of 177 and 203 mV to drive a current density of 10 mA cm–2 and robust stability for the HER and OER, respectively. Meanwhile, the (NiCo)­S2/NCNF electrodes exhibit a small voltage of 1.61 V for overall water splitting activity with an electrolyzer cell at current densities of 10 mA cm–2 over 12 h. This work presents novel insights into the bifunctional catalyst for promoting the overall water splitting via a MOF-derived nanoarchitecture and multicomponent synergy.

In situphosphoselenization induced heterointerface engineering endow NiSe2/Ni2P/FeSe2hollow nanocages with efficient water oxidation electrocatalysis performance

“…It is clearly found that the R ct value of NiFePSe was smaller than that of the other three competitors, implying optimal electron transfer and accelerated electrode kinetics. 43 Cyclic voltammetry (CV) curves were used to calculate the value of double-layer capacitance ( C dl ) to further measure the electrochemically active surface area (ECSA). Fig.…”

Synergistic Interfacial Engineering of Heterostructured Cobalt Phosphide Spheres/Cobalt Hydroxide Nanosheets for Overall Water Splitting

“…5 Although noble-metal electrocatalysts (e.g., IrO 2 /RuO 2 and Pt/C) exhibit favorable electrocatalytic performance toward water splitting, their rareness and high price severely limit their further commercialization. 6,7 Therefore, it is urgent to develop cost-effective and high-efficiency non-precious-metal bifunctional electrocatalysts for catalyzing the HER and OER, including phosphides, 7 sulfides, 8 carbides, 9 and oxides. 10 Recently, transition metal phosphides (TMPs) have attracted considerable attention probably because of the characteristics of outstanding catalytic activity, high conductivity, and low binding energy with hydrogen in alkaline solution.…”

“…However, due to the sluggish kinetics of hydrogen evolution (HER) and oxygen evolution (OER) reactions, electrochemical water splitting generally requires efficient electrocatalysts to accelerate the reaction rate of water electrolysis . Although noble-metal electrocatalysts (e.g., IrO 2 /RuO 2 and Pt/C) exhibit favorable electrocatalytic performance toward water splitting, their rareness and high price severely limit their further commercialization. , Therefore, it is urgent to develop cost-effective and high-efficiency non-precious-metal bifunctional electrocatalysts for catalyzing the HER and OER, including phosphides, sulfides, carbides, and oxides …”

Semicrystalline IrOx with Abundant Boundaries for Overall Water Splitting

“…The exploitation of new inorganic catalytic materials for efficient overall water splitting via accelerating the two half-reactions, namely, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), is of great significance for the development of the hydrogen economy. − To date, Ir/Ru oxides and metallic Pt are still the benchmark catalysts for OER and HER in terms of activity and stability, respectively. , In an integrated electrolyzer, the practical implementation of monofunctional electrocatalysts is usually limited by the mismatched working conditions . It is also noted that the development of efficient bifunctional catalysts for both OER and HER in the same solution is necessary, based on the fact that device fabrication can be simplified and thus the cost can be reduced. , However, most of the developed bifunctional electrocatalysts currently can be applied in only alkaline electrolytes. − To survive under a strongly acidic and oxidative environment for acidic overall water splitting at faster kinetics, the use of noble metals as the electrocatalysts is indispensable. − In spite of the wide application of noble metals, , individual Ir/Ru oxides or metallic Pt is monofunctionally active with regard to water splitting ut supra. , Designing bifunctional activities of noble metals remains challenging.…”