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Green hydrogen production is emerging as an essential task for future energy. Water splitting is an effective approach to yield green hydrogen with high purity. However, expensive electrocatalysts are required that can increase the production cost. Herein, a novel procedure is proposed to incorporate iridium single atoms into zirconium‐doped pure‐phase cobalt phosphide (Ir@Zr–CoP) that can adjust the electronic properties and enhance the electrochemical active sites. When Ir@Zr–CoP serves as a bifunctional catalyst for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), it requires a low overpotential of 74 and 292 mV to accomplish a current density of 10 mA cm−2. Remarkably, when the Ir@Zr–CoP based electrode is assembled as a large‐scalable anion‐exchange membrane water electrolyzer, the device requires a small cell voltage of only 1.88 V to obtain a current density of 1.0 A cm−2 with high stability for 150 h. [ABSTRACT FROM AUTHOR]

The commercialization of electrochemical water splitting technology requires electrocatalysts that are cost‐effective, highly efficient, and stable. Herein, an advanced bifunctional electrocatalyst based on single‐atom Co‐decorated MoS2 nanosheets grown on 3D titanium nitride (TiN) nanorod arrays (CoSAs‐MoS2/TiN NRs) has been developed for overall water splitting in pH‐universal electrolytes. When applied as a self‐standing cathodic electrode, the CoSAs‐MoS2/TiN NRs requires overpotentials of 187.5, 131.9, and 203.4 mV to reach a HER current density of 10 mA cm–2 in acidic, alkaline, and neutral conditions, respectively, which are superior to the most previously reported non‐noble metal HER electrocatalysts at the same current density. The CoSAs‐MoS2/TiN NRs anodic electrode also shows low OER overpotentials of 454.9, 340.6, and 508.0 mV, respectively, at a current density of 10 mA cm–2 in acidic, alkaline, and neutral mediums, markedly outperforming current OER catalysts reported elsewhere. More importantly, an electrolyzer delivered from the cathodic and anodic CoSAs‐MoS2/TiN NRs electrodes exhibits an extraordinary overall water splitting performance with good stability and durability in pH‐universal conditions. [ABSTRACT FROM AUTHOR]

Herein, an efficient multifunctional catalyst based on phosphorus and sulfur dual‐doped cobalt oxide nanosheets supported by Cu@CuS nanowires is developed for water splitting and Zn–air batteries. The formation of such a unique heterostructure not only enhances the number and type of electroactive sites, but also leads to modulated electronic structure, which produces reasonable adsorption energy toward the reactant, thereby improving electrocatalytic efficiency. The catalyst demonstrates small overpotentials of 116 and 280 mA cm−2 to achieve 10 mA cm−2 for hydrogen and oxygen evolution, respectively. As a result, a developed electrolyzer displays a cell voltage of 1.52 V at 10 mA cm−2 and long‐term stability with a current response of 92.3% after operating for 30 h. Moreover, using such a catalyst in the fabrication of a Zn–air battery also leads to a cell voltage of 1.383 V, along with a power density of 130 mW cm−2 at 220 mA cm−2. [ABSTRACT FROM AUTHOR]

A novel hybrid of small core@shell structured CoSx@Cu2MoS4 uniformly hybridizing with a molybdenum dichalcogenide/N,S‐codoped graphene hetero‐network (CoSx@Cu2MoS4‐MoS2/NSG) is prepared by a facile route. It shows excellent performance toward the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) in alkaline medium. The hybrid exhibits rapid kinetics for ORR with high electron transfer number of ≈3.97 and exciting durability superior to commercial Pt/C. It also demonstrates great potential with remarkable stability for HER and OER, requiring low overpotential of 118.1 and 351.4 mV, respectively, to reach a current density of 10 mA cm−2. An electrolyzer based on CoSx@Cu2MoS4‐MoS2/NSG produces low cell voltage of 1.60 V and long‐term stability, surpassing a device of Pt/C + RuO2/C. In addition, a Zn‐air battery using cathodic CoSx@Cu2MoS4‐MoS2/NSG catalyst delivers a high cell voltage of ≈1.44 V and a power density of 40 mW cm−2 at 58 mA cm−2, better than the state‐of‐the‐art Pt/C catalyst. These achievements are due to the rational combination of highly active core@shell CoSx@Cu2MoS4 with large‐area and high‐porosity MoS2/NSG to produce unique physicochemical properties with multi‐integrated active centers and synergistic effects. The outperformances of such catalyst suggest an advanced candidate for multielectrocatalysis applications in metal‐air batteries and hydrogen production. [ABSTRACT FROM AUTHOR]

Abstract A Pt nanodots monolayer with ultra-low surface loading of 0.48 at% integrating onto a mesoporous complex nanostructure of Cu@Cu x O nanowires (NWs) supported by a three-dimensional substrate is developed via a versatile and effective deposition strategy of the galvanic displacement between Cu monolayer and PtCl 4 2- in an effort to minimize Pt catalyst usage. The uniform and ultra-small Pt nanodots (∼2 nm) achieved full coverage on NWs leads to significant structural modulation, along with increased hierarchical and disorder degree. It also generates high Pt-Cu interaction, as evidenced by the crystal lattice deformation of metallic phases and the charge transfer from Cu to Pt, leading to enhancement towards both of hydrogen evolution (HER) and oxygen evolution (OER) processes. The hybrid exhibits low overpotential values of 72 mV and 250 mV at 10 mA cm−2 for HER and OER, respectively, and these are superior to those of other surveyed materials. The mass activity of hybrid is around 3.1 times higher than commercial Pt-C (10 wt%) for HER and 6.4 times higher than Pt-C and RuO 2 -C for OER under similar testing conditions. This research may serve as a promising method for developing electrocatalysts with high activity but minimal Pt usage towards water splitting. Graphical abstract fx1 Highlights • Low surface loading of Pt nanodots (0.48 at%) on mesoporous Cu@Cu x O NWs was prepared. • Ultra-small Pt nanodots along with its electronic modulation improved HER process. • Unique dendritic nanostructures of vertical Cu x O layers on Cu NWs improved OER. • Synergetic effect of Pt and Cu-based materials accelerated overall water splitting. • The catalyst had better catalytic and mass activity, stability than Pt/C and RuO 2. [ABSTRACT FROM AUTHOR]

The metallic (1T) transition metal dichalcogenides (TMDCs) are known for their superior electrocatalytic performance, due to their high conductivity, active basal-planes, and exposed edges. Our novel approach of coupling a metallic-NiTe 2 /Ni nano-skeleton with 1T-Co-WS 2 nanosheet in a core–shell arrangement to develop a hybrid heterostructure (1T Co-WS 2 /NiTe 2 /Ni) has helped to outperform the trifunctional-electrocatalytic activity (HER, OER, and ORR). 1T-Co-WS 2 /NiTe 2 /Ni only requires ultralow overpotential (η HER = 88 mV@10, η OER = 290 mV@30), higher half-wave potential for ORR (E 1/2 = 0.781 V vs RHE), small Tafel slopes (HER = 68 mV dec-1, OER = 98 mV dec-1, and ORR = 63 mV dec-1) with high electrocatalytic surface area and robust stability in corresponding half-cell reactions. The designed heterostructured electrocatalyst (1T Co-WS 2 /NiTe 2 /Ni) presented exceptional total water-splitting performance, requiring a low voltage of 1.521 V to yield 10 mA cm−2 current with extensive structural and electrochemical durability. Such performance could be attributed towards improved nanochannel morphology with exposed active edge, fluent electrode-kinetics, facile adsorption–desorption of reaction intermediates owing to the intrinsically tuned 1T-WS 2 by cobalt-doping, and hybridized NiTe 2 /Ni nano-skeleton. The DFT study confirmed that the incorporation of Co atoms in basal plane and the edge sites of WS 2 lattice induces the redistribution and modulation of electronic structure for fast electron/charge transfer and the synergistic coupling of 1T NiTe 2 heterostructures bolstered the electrocatalytic activity of the as-prepared catalysts. These outcomes provide a prospect towards the design and application of efficient 2D/2D heterostructured electrocatalyst for zero emission energy goal. [Display omitted] • Developed multifunctional 1T Co-WS 2 shell-nanochannels layer at the metallic NiTe 2 /Ni core–nanoskeleton sheet electrocatalyst by facile hydrothermal strategy. • Staggering HER/OER/ORR catalytic efficacy of 1T-Co-WS 2 /NiTe 2 /Ni is observed with only η HER of 88 mV @ 10 mA cm-2, η OER of 290 mV @ 30 mA cm-2 and E 1/2 of 0.781 for ORR. • Superior overall water-splitting performance of 1T-Co-WS 2 /NiTe 2 /Ni(+,−) alkaline electrolyzer, required cell potential of 1.521 V at 10 mA cm−2. • DFT reveals the redistribution and modulation of electronic structure and synergistic coupling of the heterostructures. [ABSTRACT FROM AUTHOR]

To meet the demands of the future green energy industry, there is a need for the cost-effective development of high-efficient electrocatalysts with optimal durability for water splitting and Zn-air batteries. In this work, a novel multifunctional electrocatalyst based on ultrafine Au@Co 2 N 0.67 core/shell nanodots interspersed 3D-NGr (Au@Co 2 N 0.67 /3D-NGr) with extraordinary activity and durability toward the hydrogen evolution reaction, oxygen evolution reaction, and oxygen reduction reaction has been developed that tends to show similar activity to the benchmark Pt/C and RuO 2 /C catalysts. Significantly, the Au@Co 2 N 0.67 /3D-NGr hybrid shows excellent overall water splitting potential while requiring small cell voltages of 1.58 and 1.79 V to achieve 10 and 50 mA cm−2, respectively. In addition, Zn-air batteries using the developed Au@Co 2 N 0.67 /3D-NGr hybrid demonstrate high performance, an expected open circuit potential of 1.46 V, a large power density of 142.8 mW cm−2, good rechargeability, and a high cycling life. [Display omitted] • Au@Co 2 N 0.67 /3D-NGr hybrid was preeminent multifunctional electrocatalysts towards HER, OER, and ORR. • Au@Co 2 N 0.67 /3D-NGr hybrid-based electrolyzer achieved 10 mA cm−2 catalytic current density at cell voltage of 1.58 V. • Au@Co 2 N 0.67 /3D-NGr hybrid-based Zn-air batteries demonstrated expectational performance. [ABSTRACT FROM AUTHOR]

Merging metal single atoms into a nanostructure is a novel approach to motivate the number and types of active centers for boosting catalytic activities towards both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water splitting. Herein, we reported a continuous molybdenum sulfide-carbide heterostructure-based nanosheets incorporated with ruthenium atoms (2.02 at%) and shelled over high-conductive 1D titanium nitride nanorod arrays (Ru-MoS 2 -Mo 2 C/TiN) to form a 3D hierarchical porous material via an effective synthesis strategy. The material with fine-tuned electronic structure and multi-integrated active sites exhibited small overpotentials of 25 and 280 mV at 10 mA cm−2 for HER and OER in 1.0 M KOH medium, respectively. An electrolyzer delivered from Ru-MoS 2 -Mo 2 C/TiN required an operating voltage of only 1.49 V at 10 mA cm−2, surpassing that of a commercial catalyst-based system as well as earlier reports. The good performance was identified by its enlarged electroactive surface area and superior charge-transfer ability. In addition, theoretical calculations further showed its reasonable density of states near the Fermi level together with optimum adsorption free energy for reactants. The result indicated that the Ru-MoS 2 -Mo 2 C/TiN on CC is an excellent bifunctional electrocatalyst for hydrogen production by electrochemical water splitting. [Display omitted] • A continuous Ru-doped MoS 2 -Mo 2 C heterostructure shelling over 1D TiN is synthesized. • Ru-MoS 2 -Mo 2 C/TiN demonstrates good catalytic activity for both HER and OER. • Ru-MoS 2 -Mo 2 C/TiN-based electrolyzer requires a cell voltage of 1.49 V at 10 mA cm−2. • DFT calculation suggests the optimum DOS and free energies of Ru-MoS 2 -Mo 2 C for water electrolysis. [ABSTRACT FROM AUTHOR]

Highly efficient and durable multifunctional catalysts with attractive nanoarchitectures remain challenging for next-generation rechargeable metal-air batteries and water splitting devices. Herein, for the first time, a novel copper molybdenum oxynitride anchored nitrogen-doped graphene (CuMo 2 ON@NG) is synthesized by a simple, scalable, and cost-effective pyrolysis method. The rational design of CuMo 2 ON encased in NC shells anchored onto the NG matrix to enhance the electroactive sites and boost the electron-transport behaviors for oxygen reduction/evolution reactions (ORR/OER) and hydrogen evolution reaction (HER). The optimal CuMo 2 ON@NG reveals tremendous trifunctional activities, outperform benchmark Pt/C and IrO 2. First-principles calculations demonstrate that the excellent catalytic activity of CuMo 2 ON@NG is owing to the synergistic electron transfer between the active CuMo 2 ON nanoparticles, doped N species, and graphitic carbon. Formation of the O* intermediates on CuMo 2 ON lattice in the core-shell CuMo 2 ON@NG nanohybrid is an energetic rate-determining step to attain ORR and OER activities. The CuMo 2 ON@NG air-cathode based rechargeable quasi solid-state zinc-air battery delivers an ultra-high specific capacity of 736 mAh g zn −1, an exceptional energy density of 800.75 Wh kg−1, a record power density of 176.3 mW cm−2, and excellent reversibility (330 h at 10 mA cm−2). Furthermore, the CuMo 2 ON@NG-based water splitting device achieves a cell voltage of 1.49 V at a current density of 10 mA cm−2 and excellent reversibility of 120 h at a high current density of 100 mA cm−2, outperforming the benchmark Pt/C||IrO 2 (~1.53 V at 10 mA cm−2) and reported state-of-the-art catalysts. [Display omitted] • A novel copper molybdenum oxynitride@N-doped graphene (CuMo 2 ON@NG) is established. • The optimal CuMo 2 ON@NG catalyst exhibits superior multifunctional activities. • Rechargeable zinc-air battery (ZAB) achieves high power density and long cycle life. • Water splitting device entails the ultralow cell voltage of 1.49 V to obtain 10 mA cm−2. • The series-connected rechargeable ZABs successfully driven overall water splitting. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting stands out as a highly effective and environment‐friendly strategy for generating pure hydrogen. However, the expensive catalyst required, and the low efficiency of water electrolysis, are still of concern. Herein, a novel Rh–CoSe2/CoSeO3 nanocubes heterostructure is designed with a successful robust coupling between CoSe2 and CoSeO3, and employed as a bifunctional electrocatalyst for the water splitting system. The interaction enhances metal–substrate bonding and generates the anchor sites for intermediate species, which increases the electrocatalytic efficiency and mass transport kinetics, and offers exceptional stability. The water‐splitting device demonstrates remarkable performance, with a low voltage of 1.62 V at a current density of 20 mA cm−2 and long‐lasting durability for ‐100 h. This study opens a new avenue toward the creation of extremely effective and long‐lasting catalysts to be used at an industrial scale to allow alkaline water splitting and for other energy conversion devices. The Rh–CoSe2/CoSeO3 heterostructure offers promising prospects for advancing sustainable energy technologies and positively impacting the clean energy of the future. [ABSTRACT FROM AUTHOR]

Heteroatom doping engineering has emerged as an intriguing strategy to enhance electrocatalytic efficiency. Herein, a multiple transition metal doping approach is developed through the incorporation of both Co and Nb into hierarchical MoS 2 ultrathin nanosheets directly grown on micro-TiO 2 hollow spheres (Co,Nb-MoS 2 /TiO 2 HSs) to boost the hydrogen evolution (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). The Co and Nb dual-doping effects modify the electronic structure of the host MoS 2 towards maximizing the HER, OER, and ORR performance. Additionally, the unique hollow spherical structure and heterostructured synergistic effects between the TiO 2 core and MoS 2 shell provide effective channels for electron transfer and large surface area with abundant exposed void spaces for ion diffusion/penetration. Therefore, the Co,Nb-MoS 2 /TiO 2 HSs catalyst demonstrates extraordinary activity and stability with small overpotentials of 58.8 and 260.0 mV at 10 mA cm−2 for the HER and OER, respectively. When employed as both cathodic and anodic electrode in an electrolyzer, the catalyst requires an operating voltage of 1.57 V to achieve 10 mA cm−2. The catalyst also exhibits great potential for the ORR with high onset potential of + 0.96 V and half-wave potential of +0.87 V, as well as direct four-electron transfer process. [Display omitted] • Novel structure of Co,Nb dual-doped MoS2 NSs on TiO2 hollow spheres was prepared. • Co,Nb-MoS2/TiO2 HSs showed good activity and durability for HER, OER, and ORR. • Co,Nb-MoS2/TiO2 HSs-assembled electrolyzer displayed expected performance. [ABSTRACT FROM AUTHOR]

A robust electrode material with outstanding stability at high current density is crucial for the practical application of water splitting. We present an intertwined heterostructure composed of in-situ confined cobalt nanoparticles (Co np) in nitrogen-doped carbon (N–C), derived from functionalized zeolitic imidazolate framework–67 (ZIF−67), and composited with the hetero phase bimetallic cobalt vanadium phosphide (Co 2 P−VP) through a hydrothermal reaction, room temperature aging, and chemical vapor deposition (CVD) for simultaneous phosphidation, graphitization, and reduction. The synergistic effect generated across the multiple heterointerfaces of Co 2 P, VP, and Co np in the N−doped carbon on nickel foam, as the Co 2 P–VP@N–C/Co heterostructure, exhibits outstanding electrocatalytic performance for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and electrochemical water splitting. The Co 2 P–VP@N–C/Co (+,−) alkaline electrolyzer demonstrates a low potential of 1.49 and 1.71 V to achieve current densities of 10 and 100 mA cm−2, respectively. It exhibits outstanding stability during continuous operation for 100 h at 100 mA cm−2, with 98.02 % retention. The outstanding performance is credited to the synergistic interaction and d-electronic modulation of the metallic hetero phasic Co 2 P–VP moiety and confined Co np in a functionalized N−doped porous carbonaceous heterostructure. Density Functional Theory (DFT) validates the regulation of electronic structure for efficient redistribution of local charges and electron transfer. [Display omitted] • A hetero phasic Co 2 P–VP@N–C/Co heterostructure synthized facilely. • Cobalt nanoparticles are confined via MOF. • Co 2 P–VP@N–C/Co demonstrates outstanding HER and OER activities. • Co 2 P–VP@N–C/Co (+,−) exhibits 1.49 and 1.71 V@10 and 100 mA cm−2. • It shows 100 h stability@100 mA cm−2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical NiP 2 /NbP nanosheets vertically grown on CNTs supported on 3D Ni foam (CNTs@NiP 2 /NbP). • The CNTs@NiP 2 /NbP catalyst possessed efficient water splitting performance. • The heterointerface of bimetallic phosphides and core–shell structure yielded high catalytic activity. Earth-abundant and efficient bifunctional electrocatalysts for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are crucial for electrochemical water splitting to produce green hydrogen fuel. In this work, core–shell heterostructure catalyst by NiP 2 /NiP nanosheets shelled carbon nanotubes supported on three-dimensional framework were prepared by new effective approach. Benefiting from the unique morphological feature of carbon nanotubes architecture, the synergy of inner carbon nanotubes and outer NiP 2 /NiP nanosheets, and the good couple interactions at interface between NiP 2 and NbP phases, this electrocatalyst showed low overpotential of 137.0 and 248.2 mV for HER and OER at a current density of 20 mA cm−2, respectively. These overpotentials were one of the smallest values of noble-metal-free electrocatalyst for HER and OER in alkaline electrolyte. Moreover, when the advanced catalyst was assembled in two-electrode configuration for full water electrolysis, a very low cell voltage of 1.51 V was required to achieve 10 mA cm−2 current density and a higher current density of 100 mA cm−2 was reached at a cell voltage of only 2.32 V. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1T−Mn−VS 2 @Co 2 P@CC was synthesized by hydrothermal fallowed to CVD method. • Synergism of 1T−Mn−VS 2 and Co 2 P enhances the overall water splitting. • DFT validates defect engineering with interface modeling for fast charge transfer. • As-synthesized catalyst exhibits 98 and 250 mV for HER and OER at 10 mA cm−2. • 1T−Mn−VS 2 @Co 2 P@CC electrolyzer exhibits excellent 100 h stability at 500 mA cm−2. The rational integration of a 2D layered transition metal sulfide and phosphide in a single heterostructure can bring a breakthrough to produce hydrogen through controlled manipulation of electronic structure. Here, we report a novel design of a hierarchical 2D−2D tangled 3D heterostructure of manganese-doped 1T vanadium disulfide (1T−Mn−VS 2), assembled with cobalt phosphide (Co 2 P), at the flexible carbon cloth as 1T−Mn−VS 2 @Co 2 P@CC. The HER active 1T−Mn−VS 2 bearing catalytically active edge sites, with numbers of basal planes and OER active Co 2 P, create synergism and hastening rection kinetics towards bifunctional water splitting. The heterostructure display significantly low over potential of 98 and 250 mV for HER and OER at 10 mA cm−2. The 1T−Mn−VS 2 @Co 2 P@CC (+,-) electrochemical cell needs 1.50 V to reach a current density of 10 mAcm−2. The implication of defect engineering along with interface modeling validated by DFT study, induces the regulation of electronic structure for fast redistribution of local charges/electron transfer. [ABSTRACT FROM AUTHOR]

• Hierarchical Ni–Co phosphide nanoneedle arrays supported carbon spheres is prepared. • The hybrid as bifunctional catalyst exhibits high activity toward HER and OER. • The electrolyzer of hybrid showed smaller cell voltage than device of RuO 2 /C + Pt/C. • The electrolyzer of hybrid achieved superior stability to device of RuO 2 /C + Pt/C. Due to the easy recyclability and pollution-free nature of hydrogen fuel, its highly purified production through electrochemical water splitting process has been attracting increasing attention. In this work, a hybrid of hierarchical porous nickel–cobalt phosphide nanoneedle arrays supported micro-carbon spheres was successfully synthesized and employed as robust bifunctional electrocatalyst for overall water splitting. The optimized Ni 1 Co 3 –P@CSs displayed catalytic activity with a low overpotential (η) of 57 mV at 10 mA cm−2 for hydrogen evolution and a η of 330 mV at 20 mA cm−2 for oxygen evolution, along with good stability after testing for 30 h. The water splitting cell of the Ni 1 Co 3 –P@CSs delivered smaller cell voltage at a current density of 50 mA cm−2 and much better durability than a similar device based on RuO 2 /C and Pt/C. The enhanced performance was assumed to the unique hierarchical three-dimensional urchin nanostructure of bimetallic phosphide nanoneedles, which resulted in the synergetic effects to modulate electronic properties and electroactive surface area. These improved the reactant's intermediates adsorption energy, number of exposed active sites, and various shortened channels for charge transfer and reactant/electrolyte diffusion. Our finding offers an attractive electrocatalyst with low cost and high catalytic activity for efficient water electrolysis. [ABSTRACT FROM AUTHOR]

Multiple interfaces and phases between the electrode and electrolyte play a key role in prompting the overall electrocatalysis, due to the high chances of the formation and cleavage of chemical bonds. Here, we employed the most common tactic of coupling functional components into a hybrid heterostructure with improved synergistic effects between organic and inorganics. The functional metal nodes-organic bridge ligands integrated on polyvalent tungsten oxide–carbide interfaces with highly-porous nano-dendritic architectonic is developed. The FeCu–BTC/WO 3 –WC showed excellent electrochemical half-cell (HER/OER/ORR), and Full-cell (aqueous ZAB and water electrolysis) performances with Ε 1/2, ORR = 0.81 V, η 10, OER = 249 mV, η 10, HER = 99 mV, Ε 10, water splitting = 1.531 V, and PD ZAB = 135.2 mW cm−2 with profound durability. Hence, the multi-interfacial dendritic FeCu–BTC/WO 3 –WC ternary nanocomposite offers the prospect of a good harbinger for aggressive reform of energy technologies towards the zero-emission energy goal. [Display omitted] • A unique pseudomorphic transformation synthesis protocol to fabricate highly crystalline WO 3 –WC nanorods was adopted. • FeCu–BTC MOF moiety integrated with WO 3 –WC nanorods to procure the multifunctionality in electrocatalyst (FeCu–BTC/WO 3 –WC). • Nanodendritic FeCu–BTC/WO 3 –WC with dense oxide–carbide/MOF heterointerfaces exhibits promising electrocatalytic performance in half-cell reactions (HER, OER, ORR). • Two or more functional components in nanodendritic structure showed admirable full cell device performances (water splitting and zinc–air battery). [ABSTRACT FROM AUTHOR]

In this work, smart strategies are conducted to design advanced multifunctional electrocatalysts: Co 3 S 4 /CoO x heterostructured nanosheets-assembled nanotube arrays on 3D framework integrated with single Rh atoms and subnanometer clusters. The catalyst can reach current density of 10 mA cm−2 at low overpotentials of 248.2, and 56.1 mV for oxygen evolution reaction, and hydrogen evolution reaction, respectively. The catalyst also shows very low potential of 1.32 V for urea oxidation reaction at 10 mA cm−2. A water electrolyzer that achieves current density of 10 mA cm−2 at small cell voltage of 1.45 V is prepared under action of the developed catalyst. We also conduct urea electrolysis assembled with the catalyst and find that the device requires a cell voltage of only 1.35 V to drive a current density of 10 mA cm−2, proving the great potential of our catalyst for simultaneous energy-saving H 2 production and the treatment of urea-rich wastewater. [Display omitted] • Constructing Rh-Co 3 S 4 /CoO x heterostructures for overall water and urea electrolysis. • Single Rh atoms and clusters play as promising adjutant for the host Co 3 S 4 /CoO x. • The developed Rh-Co 3 S 4 /CoO x shows extraordinary HER, OER, and UOR performance. • The overall water and urea electrolysis show excellent performance under action of the Rh-Co 3 S 4 /CoO x electrode. [ABSTRACT FROM AUTHOR]

The rational design of the highly active, durable, and cost-effective catalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) is essential for next-generation water splitting systems and zinc-air batteries. Herein, a novel strategy is demonstrated to design iron tin oxyselenide (Fe x Sn 1−x OSe) with enriched oxygen vacancies through a simple and straightforward hydrothermal and subsequent selenization process. The optimal Fe 0.33 Sn 0.67 OSe catalyst exhibits superior ORR, OER, and HER performances due to the numerous electroactive sites and high synergistic effects. The water electrolyzer requires a small voltage of 1.490 V and incredible reversibility over 24 h. Most interestingly, the Fe 0.33 Sn 0.67 OSe air-cathode based flexible ZAB exhibits a high power density of 153.96 mW cm−2 and ultralong cycle life for 400 h. This work opens a new strategy to establish highly active and durable multifunctional catalysts in next-generation energy conversion and storage systems. [Display omitted] • A novel 3D catalysts of iron tin oxyselenide grown on nickel foam is established. • The trifunctional catalyst exhibits excellent performance for OER, HER, and ORR. • Water splitting electrolyzer requires a small voltage of 1.49 V at 10 mA cm−2. • Zinc air battery delivers a peak power density of 153.96 mW cm−2, ultralong cycle-life for 400 h. [ABSTRACT FROM AUTHOR]

[Display omitted] • The oxygenated nickel tungsten selenide nanosheet have been developed and rational manipulated. • The optimal O-Ni 0.5 W 0.5 Se 2 catalyst displays exceptional performance for OER and HER. • The enriched oxygenated O-Ni 0.5 W 0.5 Se 2 improves the catalyst stability. • Water splitting devices required a small voltage of 1.56 V at 10 mA cm−2. The development of a bifunctional hierarchical nanostructure catalyst with high activity, low cost, excellent reversibility, and binder-free is an emerging key demand in industrial application for overall water splitting. In this work, a new strategy was employed for the rational design of 3D hierarchical oxygenated nickel tungsten selenide on conductive nickel foam substrate (O–Ni 1−x W x Se 2 /NF) by a low-cost hydrothermal process, followed by a partial controlled-selenization process. Owing to the enriched oxygenated intermediates and abundant active sites with nanoporous networks, the optimal O–Ni 0.5 W 0.5 Se 2 hierarchical nanostructure shows excellent catalytic activities for hydrogen evolution and oxygen evolution reactions, which exhibit a low overpotential of ∼ 109 and 238 mV at 20 mA cm−2, with remarkable durability. Most significantly, the O-Ni 0.5 W 0.5 Se 2 ||O-Ni 0.5 W 0.5 Se 2 electrolyzer required a small cell voltage of ∼ 1.56 V at 10 mA cm−2. The present study suggests a new strategy for designing highly active hierarchical 3D oxygenated enriched metal selenide as a durable bifunctional electrocatalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel Cu-implanted heterostructure of amorphous NiSe x /crystalline NiSe 2 is prepared. • Catalyst needs overpotential of 156.9 mV for HER and 339 mV for OER at 10 mA cm−2. • The catalyst-based electrolyzer requires a low cell voltage of 1.62 V at 10 mA cm−2. • The catalyst-based electrolyzer shows a long-term stability of 21.5 h in 1.0 M KOH. In this research, we designed a novel heterostructure of porous amorphous-crystalline nickel selenide incorporated with copper (Cu-(a-NiSe x /c-NiSe 2)) and shelled over one-dimensional TiO 2 nanorods (NRs) to simultaneously accelerate both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics in alkaline environment. The Cu-(a-NiSe x /c-NiSe 2)/TiO 2 NRs supported by carbon cloth displayed as an effective bifunctional catalyst, which required low overpotentials of 156.9 mV for HER and 339 mV for OER to achieve a current response of 10 mA cm−2 in 1.0 M KOH medium. An electrolyzer derived from the Cu-(a-NiSe x /c-NiSe 2)/TiO 2 NRs material allowed an operation voltage of 1.62 V at 10 mA cm−2 along with good long-term stability after 21.5 h operation towards water splitting in alkaline medium. This achievement was resulted from the fine-tuned 3D porous architecture of the amorphous NiSe x -crystalline NiSe 2 heterostructures doped by copper, which led to significant modulation of electronic properties as well as large surface of exposed electroactive site/types, thereby effectively promoting the catalytic performance. This study suggested a rational approach of structure and shape engineering to design a potential catalyst for producing green hydrogen via water spitting. [ABSTRACT FROM AUTHOR]

• 3D Ni 1―x Mo x OSe with numerous oxygen vacancies is successfully developed. • Ni 0.5 Mo 0.5 OSe exhibits superior multifunctional activities for ORR, OER, and HER. • Flexible QSS-ZAB reveals ultrahigh peak power density and ultra-long cycle life. • Water electrolyzer entails the ultralow cell voltage of 1.51 V to obtain 10 mA cm−2. • Water electrolyzer is successfully driven by series-connected flexible QSS-ZABs. Rational design of 3D nickel molybdenum oxyselenide (Ni 1-x Mo x OSe) nanoarchitectures with numerous oxygen vacancies is developed through facile and low-cost hydrothermal and followed by selenium ion modulation approach. The experimental and theoretical studies reveal that the optimal Ni 0.5 Mo 0.5 OSe possesses ultrafast charge-transfer kinetics, which would boost the catalytic activities, enhance the accessibility of electroactive sites, and increase the diffusion networks for oxygen species. Most impressively, the optimal Ni 0.5 Mo 0.5 OSe affords superior trifunctional activities, outperforming benchmark Pt/C and IrO 2 catalysts. When employed as an air-cathode in flexible Zn-air batteries, it achieves a peak power density of 166.7 mW cm−2 and outstanding durability for 300 h in ambient air. Furthermore, the water electrolyzer realizes a current density of 10 mA cm−2 at a cell voltage of 1.51 V, outperforming benchmark Pt/C||IrO 2 couple and reported state-of-the-art catalysts. This consequence provides a general strategy to explore highly efficient multifunctional catalysts with enhanced durability. [ABSTRACT FROM AUTHOR]

• 3D-dendritic nanostructure of 1T-Fe/P-WS 2 @CC in a single step reaction is fabricated. • Doping of Fe and P helps in enrichment of 1T-phase of WS 2 , activation of the basal plane and the development of nanostructures with high surface area and porosity. • 1T-Fe/P-WS 2 @CC shows exceptionally high HER and OER catalytic efficacy, required over potential of 116 mV and 267 mV at current density 10 mA cm−2 respectively. • 1T-Fe/P-WS 2 @CC alkaline electrolyzers require only 1.53 V at current density 10 mA cm−2 for overall water splitting. 1T-WS 2 is known for its higher hydrogen evolution reaction (HER) performance than 2H-WS 2. However, the lack of thermodynamic stability and absence of large-scale synthesis procedures kept 1T-WS 2 significantly ignored to date. In this report, for the first time, we have fabricated 1T-WS 2 in 3D-dendritic nanostructures over flexible carbon cloth (CC) following doping and intercalation of Fe and P (1T-Fe/P-WS 2 @CC). The HER and OER activities of 1T-Fe/P-WS 2 @CC outperform state-of-the-art electrocatalysts, demonstrating a low overpotential (η HER =116 mV, η OER =267 mV @ 10 mA cm−2), small Tafel slope (HER =65 mV dec-1, OER =70.1 mV dec-1), and significant durability. The 1T-Fe/P-WS 2 @CC (+,−) alkaline elctrolyzer also shows exceptional high performance, required only 1.53 V cell voltage at the current density of 10 mA cm−2. Overall, this work opens up a new dimension for simple and scalable fabrication of highly efficient and low-cost electrocatalyst based on WS 2. [ABSTRACT FROM AUTHOR]