Search

In this study, Fe1Pt3 nanoparticles are dispersed on MoS2 nanosheets to integrate the fascinating features of noble metal with highly exposed nanosheets. The MoS2 nanosheets supply good support for the uniform dispersion and easily accessibility of Fe1Pt3 nanoalloys, and ultrafine Fe1Pt3 nanoparticles provide a large number of active sites and enhanced catalysis/charge kinetics. The Fe1Pt3-MoS2 catalyst exhibits good hydrogen evolution performances in acidic media with low overpotential of 59 mV at current density of 10 mA cm−2 and robust catalysis kinetics (Tafel slope of 38 mV dec−1), making it high-efficiency HER catalyst with low Pt loading. [ABSTRACT FROM AUTHOR]

• Ultrafine Co–Ru alloys on N,P co-doped graphene are developed for HER. • Alloying Co with Ru improves the intrinsic activity and active site density. • N,P co-doping benefits CoRu dispersion and catalytic performance. • Showing good HER activity with η 10 of 52 mV and Tafel slope of 38 mV dec−1. Lacking inexpensive and efficiency-competitive alternatives to Pt-based electrocatalysts sets the main barrier for scalable generation of hydrogen from water splitting. Here we report an active and stable catalyst composed of ultrafine cobalt–ruthenium alloys on nitrogen and phosphorus co-doped graphene for hydrogen evolution. The nitrogen and phosphorus co-doping is beneficial for CoRu dispersion and contributes to boost the catalytic performance. Alloying cobalt with ruthenium resolves the challenge of simultaneously improving the intrinsic activity and active site density. The catalyst exhibits remarkable activity with low overpotential of 52 mV at 10 mA cm−2 and Tafel slope of 38 mV dec−1. [ABSTRACT FROM AUTHOR]

Nano-engineering is an effective strategy to achieve improved catalytic performance. A specific high-performance electrocatalyst of graphene quantum dots doped MoS 2 nanosheets with defect-rich structures and improved electrical conductivity, referred as GQDs-MoS 2 , has been rationally designed and successfully developed through a facile hydrothermal method. XRD, SEM, TEM, and Raman techniques are employed to reveal the formation and the structural features. The doping of GQDs into MoS 2 nanosheets plays the key role in enhancing the catalytic activity by creating abundant defect sites both in the edge plane and the basal plane, as well as enhancing the electrical conductivity. Endowed with this, the sample delivers remarkably improved catalytic properties for electrochemical hydrogen evolution reaction, including the large cathodic current (10 mA cm −2 at a small overpotential of 200 mV and 74 mA cm −2 at a small overpotential of 300 mV) and low onset potential (140 mV). [ABSTRACT FROM AUTHOR]

MoS 2 has emerged as an efficient hydrogen evolution catalyst and its activity is believed to be mainly determined by two factors: the amount of edge sites and electrical conductivity. To achieve improved catalytic activity, the few-layered oxygen-incorporated MoS 2 ultrathin nanosheets are prepared for the construction of hybrid nanosheets with graphene substrates using one-pot hydrothermal method for the first time. XRD, Raman, SEM, TEM, EDS and TGA techniques are used to characterize the hybrids. The moderate oxygen-incorporation into MoS 2 creates abundant edge sites and improves the conductivity. The tight coupling between the hybrid nanosheets expedites the electrical transfer. Endowed with the above advantages, the hybrid nanosheets are ideal electrocatalysts for hydrogen evolution reaction (HER) and exhibit high activity, which is demonstrated by the ultralow onset overpotential (120 mV), large cathodic current density (65.5 mA cm −2 at η = 300 mV), and small Tafel slope (51 mV decade −1 ), as well as superior cycling stability. Our enhanced understanding of this highly active MoS 2 hybrid catalyst for HER may facilitate the development of economical electrochemical hydrogen production systems. [ABSTRACT FROM AUTHOR]

Promoting the intrinsic electronic structure and conductivity by hetero-element doping technique is an effective solution to acquire improved electrochemical energy storage and conversion activities of transition metals based materials. Herein, the rationally designed integrated electrode of vanadium doped NiS nanoparticles supported on carbon fiber cloth (V–NiS/ CC) is prepared via a one-step hydrothermal method. The physical analysis reveals the successful and homogeneous doping of vanadium in NiS. The electrochemical measurements indicate that V-doping is crucial to improve the electrochemical properties of NiS for lithium storage and water splitting. As anode for lithium-ion battery, V–NiS/CC exhibits high reversible capacity of 1056.3 mAh g−1 after 100 cycles at 0.1 A g−1 and good rate performance. Additionally, a low overpotential of 121 mV is achieved to generate catalysis current density of 10 mA cm−2 when V–NiS/CC serves for electrocatalytic hydrogen evolution. The remarkable electrochemical properties should be due to the optimized electronic structure and conductivity that are endowed by vanadium doping. This work provides a solid proof to design heteroatom doped transition metal sulfides for promising applications in electrochemical energy storage and conversion. [Display omitted] • Vanadium doped NiS nanoparticles are supported on carbon fiber cloth. • Optimized intrinsic activity and improved conductivity are obtained. • High capacity, stable cycle and good rate capability are shown as LIBs anode. • High-efficiency HER performances are achieved in alkaline solution. [ABSTRACT FROM AUTHOR]

• Electrochemical activation induces surface reconstruction of CoMo-LDH nanosheets. • The optimized electronic structure and enhanced intrinsic activity are obtained. • The increased catalysis sites and promoted charge transfer are achieved. • Generating 100 mA cm−2 at low overpotentials of 202 mV for HER. Surface reconstruction emerging in the electrochemical oxygen evolution process is regarded to be significantly important for the activated catalysis efficiency, however, which is rarely recognized for hydrogen evolution reaction (HER). Here, the electrochemical activation of CoMo layered double hydroxide (CoMo-LDH) nanosheet arrays is demonstrated to significantly activate the electrochemical HER property. The catalysis performance improvement originates from the surface transformation of CoMo-LDH to Co(OH) 2 /CoOOH, as well as the dissolution of Mo and its adsorption on the catalyst surface in K 2 Mo 3 O 10 phase. Based on the combined benefits of optimized electronic structure, increased catalysis sites, and promoted charge transfer, the overpotentials at catalysis current densities of 10 and 100 mA cm−2 are as low as 113 and 202 mV. This study demonstrates the electrochemical activation strategy to drive the surface reconstruction of bimetal hydroxides for enhanced HER performance, inspiring the research interests on the reconstruction and activation enhancement behaviors of HER electrocatalysts. [ABSTRACT FROM AUTHOR]

• Electrodeposition synthesis of Co 4 S 3 on NiCo LDH nanosheet array. • Lattice defects and distortions are achieved at interface as active sites. • Accelerated charge transfer and kinetics are obtained. • Improved HER activity in alkaline media is acquired. Interface engineering is considered as an effective solution to fabricate efficient composite catalysts for water electrolysis. We implement a two-step electrodeposition method for designing hetero-interfaces of Co 4 S 3 nanocrystals on NiCo layered double hydroxide (NiCo LDH) nanosheet arrays as electrocatalyst for hydrogen evolution. The interface constructing achieves improved hydrogen evolution catalysis by inducing lattice defects and distortions as active sites, and accelerating charge transfer and kinetics. The Co 4 S 3 -NiCo LDH/CC exhibits efficient catalysis performances with overpotential of 124 mV at 10 mA cm−2. This work provides not only advanced composite catalyst but also the facile and effective electrodeposition strategy for constructing hetero-interface electrocatalysts. [ABSTRACT FROM AUTHOR]

Despite the intensive focuses on developing Prussian blue analogues (PBAs) derived catalysts, the direct utilization of PBAs for electrochemical water splitting to produce oxygen and especially hydrogen sources has rarely been reported, because of lacking effective strategies to improve the active site density and electrical transport of PBAs. Herein, we resolve such challenges by constructing the cubic NiCo-PBA bricks assembled 2D nanowalls on Ni foam (NF) through a Ni(OH) 2 nanosheet confined template technique. A great amount of sites are generated along the borders of brick subunits, and the 2D feature supplies downscaled charge diffusion path and high accessible surface area. Therefore, NiCo-PBA/NF exhibits impressive water electrolysis activities, with low overpotentials of 200 and 62 mV at 10 mA cm−2 for oxygen evolution reaction and hydrogen evolution reaction, respectively. Moreover, the NiCo-PBA/NF coupled two-electrode system achieves a low cell potential of 1.49 V at 10 mA cm−2 for overall water splitting, which is even better than the noble metal based IrO 2 -Pt/C system. This contribution sheds light on boosting the catalytic activity of PBAs and metal-organic frameworks toward water splitting, sensors, and other energy-related applications. Image 1 • NiCo-PBA cubes built nanowalls are developed using Ni(OH) 2 nanosheets. • Showing excellent OER activity with 200 mV at 10 mA cm−2. • Ni atoms are active but Co atoms in [Co(CN) 6 ] are inactive during OER. • Demonstrating the impressive HER activity that is close to Pt/C. • Showing excellent bifunctionality for overall water splitting. [ABSTRACT FROM AUTHOR]

After years of development, boosting the electrochemical hydrogen evolution performance of MoS 2 catalyst through the traditional methods, such as defect engineering and conductivity improvement, has reached their limit. In this work, we propose a novel functional catalyst that is fabricated by hybrid two-dimensional nanostructures composed of MoS 2 nanosheets and CoMo 2 S 4 nanoplates in situ grown on graphene substrate for electrochemical hydrogen evolution reaction. The MoS 2 -CoMo 2 S 4 /graphene hybrid catalyst shows robust hydrogen evolution performance with low onset potential of 110 mV, high cathode current density of 85 mA cm −2 at η = 300 mV, and small Tafel slope of 42 mV dec −1 , as well as good durability. The excellent hydrogen evolution performance of the hybrid catalyst is likely attributed to the nonequilibrium composition, 2D structural advantages, conductive graphene substrate, and the electrocatalytic synergistic effect between MoS 2 and CoMo 2 S 4 . [ABSTRACT FROM AUTHOR]

Advanced materials for energy conversion and storage are central to clean and reliable energy research. Herein, three-dimensional (3D) architectures composed of MoS 2 -graphene hybrid nanosheets are synthesized via a simple solvothermal method for this purpose. The architectures are self-assembled with hybrid nanosheets, which are fabricated through the in situ growth of few-layer MoS 2 nanosheets on the surface of graphene substrates. Rooted in the intriguing advantages of sheet-on-sheet structures and 3D features, the composite materials exhibit improved electrochemical lithium storage performances when used as anode materials, in terms of high reversible capacity, superior cycling stability (904 mAh g −1 after 200 cycles at 200 mA g −1 ), and high rate capability. It is also employed as integrated electrode for electrochemical water splitting and delivers remarkably enhanced catalytic performance for hydrogen evolution, such as low onset overpotential (110 mV), small Tafel slope (47 mV decade −1 ), and stable cycling performance. [ABSTRACT FROM AUTHOR]

• Hybrid 2D SnS-Ni 3 S 2 nanostructure on NF is solvothermally synthesized. • Lattice defects are achieved on interface as catalysis sites. • Good bifunctionality of HER and OER is obtained for water splitting. • Low cell voltage of 1.66 V for a high current density of 100 mA cm−2. Efficient and cheap catalysts that simultaneously catalyze hydrogen evolution and oxygen evolution are urgently desired. Herein, nickel foam supported hybrid SnS-Ni 3 S 2 is firstly developed via a solvothermal method as advanced dualfunctional catalysts in alkaline media. TEM and electrochemical tests reveal that, the hetero-interface between SnS and Ni 3 S 2 supplies a large number of defects as catalysis sites for improved activities. In addition, composite catalyst acquires improved charge transfer for catalysis. The present sample exhibits good bifunctionality with low overpotentials of 145 mV at 10 mA cm−2 for hydrogen evolution and 298 mV at 20 mA cm−2 for oxygen evolution. For overall water splitting, a low cell voltage of 1.66 V could generate a high current density of 100 mA cm−2 in a two-electrode cell, exhibiting great promise for practical application. [ABSTRACT FROM AUTHOR]

• Heterostructure of Ru 2 P particles decorated Ni 2 P nanosheets is prepared. • Synergism induces accelerated kinetics and intrinsic activity. • Improved active sites density and enhanced charge transfer are obtained. • Showing robust activity and stability for HER in wide pH range. Lacking efficient and pH-universal catalysts is currently the main obstacle for the large-scale production of hydrogen through electrochemical water splitting. The hetero material of Ru 2 P nanoparticles and Ni 2 P nanosheets is constructed on carbon fiber cloth as pH-tolerant catalyst for hydrogen generation. The designed heterointerface provides synergism and structure advantages for improved intrinsic catalysis activity, more accessible active sites, and enhanced charge transfer for hydrogen evolution. The electrochemical measurements demonstrate the active hydrogen production properties, such as low overpotentials (46 mV, 47 mV, and 51 mV in 0.5 M H 2 SO 4 , 1 M KOH, and 1 M phosphate-buffered saline, respectively) at a current density of 10 mA cm−2, as well as rapid catalysis kinetics with small Tafel slopes and good stability. [ABSTRACT FROM AUTHOR]

• Uniformly dispersed CuRu alloy nanoparticles are supported on carbon black. • Improved intrinsic HER activity is obtained. • Increased site density and enhanced charge transfer are acquired. • Pt-like HER activities are achieved in both neutral and alkaline solutions. There is an increasing demand for efficient electrocatalysts for hydrogen evolution reaction (HER) in neutral solution. Herein, uniformly dispersed CuRu alloy nanoparticles on carbon black (CuRu/CB) are firstly synthesized for robust HER. Based on the combined benefits of improved intrinsic activity, increased site density, and enhanced charge transfer, the as-obtained CuRu/CB exhibits Pt-like catalysis activity in both neutral and alkaline solutions, with exchange current densities of 1.02 and 1.09 mA cm−2 that are comparable to Pt/C of 1.32 and 1.44 mA cm−2, respectively. For splitting water, CuRu/CB generates the current density of 10 mA cm−2 at 91 and 85 mV in 1 M phosphate-buffered saline and 1 M KOH, respectively. [ABSTRACT FROM AUTHOR]

• Core-shell catalyst of graphene layer coated MoNi 4 -NiMoO 4 is developed. • High intrinsic activity and large ECSA are achieved. • Graphene layer accelerates charge transfer and benefits for durability. • Low overpotentials of 55 and 206 mV at 10 mA cm−2 for HER and OER. • High bifunctionality of 1.44 V at 10 mA cm−2 for overall water splitting. Developing active and cheap bifunctional electrocatalysts is crucial and challenging for overall water splitting. This work reports a core-shell structured catalyst supported on nickel foam, which is composed of hybrid MoNi 4 alloy and NiMoO 4 encapsulated in graphene shell layer. The core catalyst of MoNi 4 -NiMoO 4 supplies robust intrinsic activity and high conductivity. The graphene shell accelerates the charge transfer and provides additional protection for core catalyst. Hence, the present G@MoNi 4 -NiMoO 4 /NF exhibits excellent catalytic properties for alkali water splitting, with low overpotentials of 55 mV and 206 mV at 10 mA cm−2 for HER and OER, respectively. The efficient activity for overall water splitting is further demonstrated by a low cell voltage of 1.44 V at 10 mA cm−2 in the bifunctional G@MoNi 4 -NiMoO 4 /NF electrodes assembled electrolyzer, showing great promise for practical application. [ABSTRACT FROM AUTHOR]