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Phase engineering is an efficient strategy for enhancing the kinetics of electrocatalytic reactions. Herein, phase engineering was employed to prepare high‐performance phosphorous‐doped biphase (1T/2H) MoS2 (P‐BMS) nanoflakes for hydrogen evolution reaction (HER). The doping of MoS2 with P atoms modifies its electronic structure and optimizes its electrocatalytic reaction kinetics, which significantly enhances its electrical conductivity and structural stability, which are verified by various characterization tools, including X‐ray photoelectron spectroscopy, high‐resolution transmission electron microscopy, X‐ray absorption near‐edge spectroscopy, and extended X‐ray absorption fine structure. Moreover, the hierarchically formed flakes of P‐BMS provide numerous catalytic surface‐active sites, which remarkably enhance its HER activity. The optimized P‐BMS electrocatalysts exhibit low overpotentials (60 and 72 mV at 10 mA cm−2) in H2SO4 (0.5 M) and KOH (1.0 M), respectively. The mechanism of improving the HER activity of the material was systematically studied using density functional theory calculations and various electrochemical characterization techniques. This study has shown that phase engineering is a promising strategy for enhancing the H* adsorption of metal sulfides. [ABSTRACT FROM AUTHOR]

The escalating urgency to mitigate climate change and enhance energy security has prompted heightened exploration of hydrogen production via electrocatalysis as a viable alternative to conventional fossil fuels. Among the myriad of electrocatalysts under investigation, two-dimensional (2D) metal–organic frameworks (MOFs) stand out as a particularly appealing option. Their unique properties, including a large active specific surface area, distinctive pore structure, ample metal active sites, ultra-thin thickness, superior ion transport efficiency, fast electron transfer rate, and the ability to control the morphological synthesis, endow these frameworks with exceptional versatility and promising potential for electrocatalytic applications. In this review, we delineate the structural features and advantages of 2D MOFs and their derivatives. We proceed to summarize the latest advancements in the synthesis and utilization of these materials for electrocatalytic hydrogen evolution reactions (HER) and oxygen evolution reactions (OER). Finally, we scrutinize the potential and challenges inherent to 2D MOFs and their derivatives in practical applications, underscoring the imperative for continued research in this captivating field of electrocatalysis. [ABSTRACT FROM AUTHOR]

Interfacial microenvironment modulation has been proven to be a promising route to fabricate highly efficient catalysts. In this work, the lattice defect‐rich NiS2/MoS2 nanoflakes (NMS NFs) electrocatalysts are successfully synthesized by a simple strategy. Benefiting from the abundant lattice defects and modulated interfacial microenvironment between NiS2 and MoS2, the prepared NMS NFs show superior catalytic activity for water splitting. Particularly, the optimized NMS NFs (the molar ratio of Ni:Mo = 5:5) exhibit remarkable catalytic activity toward overall water splitting with a voltage of 1.60 V at 10 mA cm−2 in alkaline media, which is lower than that of the noble‐metal‐based electrocatalysts (1.68 V at 10 mA cm−2). The NMS NFs electrocatalysts also show exceptional long‐term stability (>50 h) for overall water splitting. The density functional theory results demonstrate that the injection of NiS2 into MoS2 can greatly optimize the catalytic kinetics and reduce the energy barrier for hydrogen/oxygen evolution reactions. The work does not only offer a promising candidate for a highly efficient water splitting electrocatalyst but also highlights that interfacial microenvironment modulation is a potential strategy to optimize the catalytic kinetics. [ABSTRACT FROM AUTHOR]

Here, we demonstrate the synthesis of sheet-shaped Co2P grown on carbon cloth (sheet-shaped Co2P-CC) through a facile route. Electrochemical measurements indicated that sheet-shaped Co2P-CC with a loading of 0.6 mg cm−2 Co2P (denoted Co2P-CC-0.6) exhibits exceptional electrocatalytic activity in the hydrogen evolution reaction (HER), with an overpotential of 94 mV at a current density of 10 mA cm−2 and a small Tafel slope of 80 mV decade−1 in 1 M KOH. Similarly, sheet-shaped Co2P-CC-0.6 was also found to be an excellent electrocatalyst for the HER in 0.5 M H2SO4 and in 0.5 M phosphate buffer solution (PBS), with overpotentials of 95 and 231 mV at a current density of 10 mA cm−2, respectively. Sheet-shaped Co2P has a large surface area, meaning that it can provide a relatively large number of active sites on its surface, and CC is an highly conductive substrate that, when used in conjunction with Co2P, can enhance the conductivity of the electrocatalyst. These outstanding results show that sheet-shaped Co2P-CC could be an excellent candidate for a highly efficient electrocatalyst. [ABSTRACT FROM AUTHOR]

Metal sulfides are considered excellent materials for oxygen evolution reaction because of their excellent conductivity and high electrocatalytic activity. In this report, the NiS-Cu2S composites were prepared on copper foam (NiS-Cu2S-CF) using a facile synthetic strategy. The scanning electron microscopy results confirmed that the NiS nanoneedles were successfully grown on Cu2S nanoflakes, greatly increasing the active sites. Particularly, the optimized 15% NiS-Cu2S-CF composite demonstrated excellent oxygen evolution activity with a small overpotential of 308 mV@20 mA cm−2, which is significantly smaller than that of noble metal-based electrocatalysts and other NiS-Cu2S-CF composites. The enhanced oxygen evolution activity is attributed to the unique morphology that can provide ample active sites, rich ion-transfer pathways, and the synergistic effect between NiS and Cu2S, which can boost the electron transfer rate. [ABSTRACT FROM AUTHOR]

In this study, cobalt phosphide (CoP 2) was synthesized onto a Nickel foam (NF) support via phosphorylation under an N 2 atmosphere. The resulting material was then coated with tetrahydroxyquinone (THQ), a conjugated microporous polymer, using a hydrothermal method. The as-synthesized CoP 2 /THQ@NF showed remarkable electrocatalytic performance for the hydrogen evolution reaction and excellent durability in acidic electrolytes. This was attributed to the synergistic effect of the NF support, CoP 2 , and THQ, which led to a modified electronic structure of CoP 2 and a high electron transfer rate of THQ. A low overpotential of 137 mV was required in a 0.5 M H 2 SO 4 solution to achieve a current density of 10 mA cm−2. • Integration of electrically conjugated polymers with non-precious metal phosphates boosts HER catalytic efficiency. • The development of CoP 2 /THQ@NF hybrid electrocatalysts through systematic methodological approaches is overviewed. • Merging organic polymers with inorganic materials elevates the catalytic prowess of non-precious metal catalysts. [ABSTRACT FROM AUTHOR]

Abstract In this work, nanosheet-shaped CuS (NS CuS) is successfully grown on carbon cloth (CC) by a two-step route in combination with electrodeposition and hydrothermal treatment via in situ sulfidations of Cu 2 O and Cu with exposure to thiourea at 120 °C or 24 h. Transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffractometry are performed to characterize the microstructure, morphology, composition, and crystal structure of the NS CuS CC samples. The electrochemical measurements demonstrate that the synthesized NS CuS CC electrocatalysts possess outstanding oxygen evolution reaction (OER) performance and superior long-term durability in 1 M KOH electrolyte. In particular, the NS CuS CC synthesized via the electrodeposition process at an applied current of 1.5 mA shows a low overpotential for the OER (358 mV at 10 mA/cm2), which is close to that of commercial IrO 2 (346 mV at 10 mA/cm2). The exceptional OER property is ascribed to the NS CuS having a large surface area to offer abundant reaction active sites and to the CC network structures supplying more ions and charge transfer channels during the electrocatalytic process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical CoS 2 /MoS 2 nanoflakes were successfully grown on graphene (CMSGr). • Hierarchical morphology provides more reaction sites and abundant charge transfer pathways. • The optimized CMSGr catalyst presents low overpotentials of 53 and 255 mV for HER and OER. • The optimized CMSGr catalyst shows a low voltage of 1.55 V for water splitting. Construction of cost-efficient and high-performance overall water splitting electrocatalysts for generating hydrogen and oxygen has recently received increasing research attention. Herein, hierarchical CoS 2 /MoS 2 (CMS) nanoflakes were successfully decorated on graphene (denoted as CMSGr) as an efficient electrocatalyst for overall water splitting. Owing to the distinct hierarchical flakes morphology, and optimized interfacial microenvironment between CoS 2 and MoS 2 , the fabricated CMSGr composites exhibit enhanced hydrogen and oxygen evolution reaction (HER/OER) activity. In particular, the optimized CMSGr-3 electrocatalyst presents the small overpotentials of 53 and 255 mV for HER and OER, and a low voltage of 1.55 V for overall water splitting in alkaline media under 10 mA cm−2. Theoretical calculations confirm that introducing CoS 2 into MoS 2 can greatly tune the electronic structure and optimize the adsorption energy during the water splitting. This work demonstrates that tuning the interfacial microenvironment of the binary metal sulfide composites is an effective route for developing high-performance water splitting electrocatalysts. [ABSTRACT FROM AUTHOR]