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The development and utilization of electrochemical energy conversion and storage devices can maximize intermittent renewable energy and balance environmental issues. Aqueous metal‐redox bicatalyst batteries, incorporating value‐added electro‐reduction reactions during discharge process at the cathode, are considered a particularly attractive alternative for simultaneous electricity generation and valuable chemical production. In this review, for the first time, a holistic and subtle description of value‐added metal‐redox bicatalyst batteries is made, focusing on recent efforts to optimize the energy conversion/chemical production‐involved cathodic discharging reactions, including CO2 reduction reaction (CO2RR), nitrogen reduction reaction (NRR), nitric oxide reduction reaction (NORR), nitrate reduction reaction (NO3−RR), nitrite reduction reaction (NO2−RR), hydrogen evolution reaction (HER), and acetylene reduction reaction (ARR). A macroscopic understanding of design principles in terms of anodes, cathodes, and reaction parameters is provided. Some mechanism explorations, feasibility analyses, technoeconomic assessments, device combinations, and associated comparisons are involved to deepen the understanding of different systems and evaluate their application prospects. Perspectives on and opportunities for future research directions are also outlined. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) comprising five or more elements in near-equiatomic proportions have attracted ever increasing attention for their distinctive properties, such as exceptional strength, corrosion resistance, high hardness, and excellent ductility. The presence of multiple adjacent elements in HEAs provides unique opportunities for novel and adaptable active sites. By carefully selecting the element configuration and composition, these active sites can be optimized for specific purposes. Recently, HEAs have been shown to exhibit remarkable performance in electrocatalytic reactions. Further activity improvement of HEAs is necessary to determine their active sites, investigate the interactions between constituent elements, and understand the reaction mechanisms. Accordingly, a comprehensive review is imperative to capture the advancements in this burgeoning field. In this review, we provide a detailed account of the recent advances in synthetic methods, design principles, and characterization technologies for HEA-based electrocatalysts. Moreover, we discuss the diverse applications of HEAs in electrocatalytic energy conversion reactions, including the hydrogen evolution reaction, hydrogen oxidation reaction, oxygen reduction reaction, oxygen evolution reaction, carbon dioxide reduction reaction, nitrogen reduction reaction, and alcohol oxidation reaction. By comprehensively covering these topics, we aim to elucidate the intricacies of active sites, constituent element interactions, and reaction mechanisms associated with HEAs. Finally, we underscore the imminent challenges and emphasize the significance of both experimental and theoretical perspectives, as well as the potential applications of HEAs in catalysis. We anticipate that this review will encourage further exploration and development of HEAs in electrochemistry-related applications. [ABSTRACT FROM AUTHOR]

Highlights: Ultrathin P and Fe co-doped NiSe2 nanosheets supported on modified Ni foam are synthesized, which shows desirable bifunctional electrocatalytic hydrogen evolution reaction (HER)/hydrazine oxidation reaction (HzOR) performance in hydrazine-assisted water electrolysis and Zn-Hz battery. The coexistence of P and Fe heteroatoms induces an accelerated "2 + 2" reaction mechanism with a two-step HER process and a two-step HzOR step. Hydrazine-assisted water electrolysis is a promising energy conversion technology for highly efficient hydrogen production. Rational design of bifunctional electrocatalysts, which can simultaneously accelerate hydrogen evolution reaction (HER)/hydrazine oxidation reaction (HzOR) kinetics, is the key step. Herein, we demonstrate the development of ultrathin P/Fe co-doped NiSe2 nanosheets supported on modified Ni foam (P/Fe-NiSe2) synthesized through a facile electrodeposition process and subsequent heat treatment. Based on electrochemical measurements, characterizations, and density functional theory calculations, a favorable "2 + 2" reaction mechanism with a two-step HER process and a two-step HzOR step was fully proved and the specific effect of P doping on HzOR kinetics was investigated. P/Fe-NiSe2 thus yields an impressive electrocatalytic performance, delivering a high current density of 100 mA cm−2 with potentials of − 168 and 200 mV for HER and HzOR, respectively. Additionally, P/Fe-NiSe2 can work efficiently for hydrazine-assisted water electrolysis and Zn-Hydrazine (Zn-Hz) battery, making it promising for practical application. [ABSTRACT FROM AUTHOR]

Supramolecular self-assembly as a breakthrough methodology in the nanoscience and nanotechnology fields has attracted increasing attention. Highly ordered self-assembled supramolecular nanostructures aim to emulate natural light-harvesting and energy transfer and electron transfer processes, which have been an active and rapidly developing field for visible-light-driven photocatalytic applications. This Research Update aims to present the recent progress of the self-assembly of π-conjugated molecules, including perylene diimides (PDIs), porphyrin, and co-assembly of peptide–porphyrin as well as the shape-defined functional hierarchical structures. First, the basic principles of π-conjugated molecular structure design are described. The two nitrogen positions and the bay positions of PDIs can effectively regulate their electronic properties and geometric skeleton, and the functional groups and the good solvents of porphyrin effectively determine the choice of self-assembly methods. Then, the key morphology dependent optoelectronic properties and charge-transport and energy-transport functionalities are also discussed. These self-assembled supramolecular nanostructures' inherent optoelectronic properties correlated with applications in photocatalytic water splitting into hydrogen evolution are overviewed. By now, the self-assembled In(III) meso-tetraphenylporphine (InTPP) porphyrin nanostructures exhibited the highest photocatalytic hydrogen generation activity among the reported supramolecular nanostructures owing to the central metal of porphyrin and small size of the InTPP nanostructure. Finally, perspectives on the crucial issues and potential future research directions are addressed. This Research Update will provide a new reference for building high performance, stable, and durable photosensitizers based on the supramolecular assembly. [ABSTRACT FROM AUTHOR]

Over the past decade, transition metal phosphate materials have attracted enormous interest for various functional devices. In addition to being low‐cost, earth‐abundant and environmentally benign, transition metal phosphates have several unique advantages including high stability, unique chemical/physical characteristics and tunable multifunctionality, making them ideally suited for advanced highly‐efficiency energy conversion and storage applications. In this Review, the synthetic strategies for transition metal phosphates are summarized, and the most recent advances in the development of transition metal phosphates are described for efficient electrocatalysis such as oxygen evolution, hydrogen evolution and oxygen reduction reactions, highlighting the impact of their morphologies and structures on the electrochemical performance and practical applications in overall water splitting and rechargeable metal‐air batteries. Finally, the challenges facing the development of transition metal phosphates in the field of energy conversion and storage are outlined, together with directions of further research and perspectives. [ABSTRACT FROM AUTHOR]

As hydrogen has been increasingly considered as promising sustainable energy supply, electrochemical overall water splitting driven by highly efficient non‐noble metal electrocatalysts has aroused extensive attention. Transition metal phosphides (TMPs) have demonstrated remarkable electrocatalytic performance, including high activity and robust durability towards hydrogen evolution reaction (HER) in acidic and alkaline as well as neutral electrolytes. In this Review, up‐to‐date progress of TMP‐based HER electrocatalysts is summarized. Various synthesis strategies of TMPs based on selected phosphorus sources are presented, and the reaction mechanisms of HER as well as the contribution of phosphorus in the TMPs to HER activity are briefly discussed. The multiscale approaches for promoting the activity and stability of TMP‐based catalysts are discussed with respect to intrinsic electronic structure, hybrids, microstructure, and working electrode interface. Some crucial issues and future perspectives of TMPs are pointed out. These modulated approaches and challenges are also instructive for constructing other high‐activity energy‐related electrocatalysts. [ABSTRACT FROM AUTHOR]

Hydrogen (H 2) is a category of green energy with high energy density, which can be prepared by water electrolysis. Hydrogen evolution reaction (HER) has received extensive attention. Nevertheless, it is urgent to solve the shortage of highly efficient catalysts. Platinum (Pt), the most excellent HER catalyst, is restricted in industrial promotion due to its high cost and scarcity. Amounts of low-price, earth-abundant catalysts with high efficiency and stability have been then studied, especially transition metal compounds that receive enormous interest as a replacement for noble metal-based catalysts. Furthermore, one-dimensional (1D) nanomaterials have been widely applied owing to their unique structures and properties. In this review, the latest research progress on the 1D transition metal compound nanostructures for electrocatalyzing HER is summarized. The improved strategies and weaknesses of 1D catalysts in HER are discussed. An outlook of future development trends toward highly efficient and stable electrochemical catalysts is also provided. [Display omitted] • Review on HER catalytic activity of 1D transition metal compounds. • Comparison of TMPs, TMCs, TMOs, TMSs, TMNs in HER catalytic activity. • Role of three improved strategies on electrochemical HER. • Strategies for preparing 1D nanomaterials. [ABSTRACT FROM AUTHOR]

Abstract: Photocatalytic hydrogen production is crucial for solar‐to‐chemical conversion process, wherein high‐efficiency photocatalysts lie in the heart of this area. A photocatalyst of hierarchically mesoporous titanium phosphonate based metal–organic frameworks, featuring well‐structured spheres, a periodic mesostructure, and large secondary mesoporosity, are rationally designed with the complex of polyelectrolyte and cathodic surfactant serving as the template. The well‐structured hierarchical porosity and homogeneously incorporated phosphonate groups can favor the mass transfer and strong optical absorption during the photocatalytic reactions. Correspondingly, the titanium phosphonates exhibit significantly improved photocatalytic hydrogen evolution rate along with impressive stability. This work can provide more insights into designing advanced photocatalysts for energy conversion and render a tunable platform in photoelectrochemistry. [ABSTRACT FROM AUTHOR]

Hydrogen, as a clean energy, has broad prospects in renewable energy and environmental protect in the future. Mo 2 N is a promising candidate in electrocatalyzing the hydrogen evolution reaction (HER) due to its low-cost and resembled electronic properties. In this work, mesoporous Mo 2 N/NC composite catalysts are synthesized by polymerizing p -phenylenediamine ( p -PDA) with ammonium heptamolybdate and following calcination under N 2 atmosphere. These catalysts show excellent HER performance in 0.5 M H 2 SO 4 solution, allowing a low overpotential of 217 mV to produce H 2 at the electric current density of 10 mA cm −2 with catalyst loading of 0.5 mg cm −2 . After 1000 cycles of acceleration degradation tests, Mo 2 N/NC remains negligible overpotential losses. These stable electrochemical properties are mainly related to the strong interaction of Mo 2 N and NC materials, which accelerates the electron transfer further for hydrogen evolution, besides the unique mesoporous structures benefitting to the transmission of the electrolyte. This work also reveals the importance of amine’s structure in synthesizing high-performance Mo 2 N anchored on N-doped carbon materials. [ABSTRACT FROM AUTHOR]

Polydopamine-derived N,P-codoped microporous carbon spheres are rationally synthesized through the self-polymerization of dopamine induced by the phosphonic species, showing efficient performance towards electrocatalytic oxygen reduction and hydrogen evolution reactions, due to the well-developed porosity and doping effect. [ABSTRACT FROM AUTHOR]

Suitable electrocatalysts for industrial water splitting can veritably promote practical hydrogen applications. Guided by density functional theory calculations, the interface-rich Ni 2 P-NiSe 2 nanoparticles anchored on amorphous MoO x nanorods on nickel foam (Ni 2 P-NiSe 2 /MoO x /NF) are fabricated. Ni 2 P-NiSe 2 /MoO x /NF exhibits exceptional HER performance with overpotentials of 23 and 263 mV at 10 and 500 mA cm−2, outperforming most reported non-Pt based electrocatalysts reported hitherto. Remarkably, the excellent oxygen evolution activity (241 mV at 10 mA cm−2) of Ni 2 P-NiSe 2 /MoO x /NF further realizes the full electrolyzer requiring the voltage of 1.63 V at 50 mA cm−2 with robust stability (1000 h at 20 mA cm−2) in 1.0 M KOH. At industrial conditions (30% KOH, 65 °C), only 2.02 V is required to reach 1000 mA cm−2 with satisfying durability (200 h at 200 mA cm−2). When deployed in anion exchange membrane water electrolyzer, the catalyst achieves 1.3 A cm−2 at 2.7 V, associated with the prolonged stability. [Display omitted] • Electronic structure and localized charge density at Ni 2 P-NiSe 2 heterointerface are optimized when coupling with MoO 2. • Optimized heterointerfaces facilitated water/hydrogen adsorption and reduced energy barrier for water dissociation. • Fabricated Ni 2 P-NiSe 2 /MoO x /NF exhibited exceptional HER and OER performance under industrial conditions. • AEM water electrolyzer with Ni 2 P-NiSe 2 /MoO x /NF showed larger current density and prolonged stability. [ABSTRACT FROM AUTHOR]

• Al-doped Ni 2 P nanoflowers exhibit excellent HER, HzOR and hydrazine-assisted water splitting activity. • Al induced electron redistribution and intermediate energy optimization contribute to the enhanced activity. • An integrated system consisting of Zn-hydrazine battery and hydrazine-assisted water splitting driven by sustainable solar energy is proposed. Hydrazine-assisted water electrolysis emerges as a promising strategy to replace conventional device for effective hydrogen generation. Limited to the great difference of intermediate adsorption energy for hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR), the design and fabrication of bifunctional catalysts is still a knotty challenge in industrial conditions. Herein, Al-doped Ni 2 P nanoflower architecture grown in-situ on nickel foam (Al-Ni 2 P/NF) is fabricated through the combination of hydrothermal process and subsequent phosphorization treatment. Ascribed to the redistribution of electron state and optimization of reaction intermediate energy induced by Al, Al-Ni 2 P/NF expresses distinguished bifunctional catalytic performance with ultralow potentials of −205 and 300 mV at 500 mA cm−2 for HER and HzOR, respectively. When integrated into hydrazine-assisted water splitting as both the anode and cathode, only 0.717 V is required to reach a large current density of 500 mA cm−2. Specially, a novel integrated system driven entirely by sustainable solar energy is proposed, generating energy-saving hydrogen and purify hydrazine-containing sewage simultaneously. This work provides an attracting and practical path for accelerating the development of hydrogen economy. [ABSTRACT FROM AUTHOR]

Defect and interfacial engineering are employed to design and construct a novel CZS/CoPPi-M composite photocatalyst, which exhibits excellent photocatalytic H 2 production activity. [Display omitted] Photocatalysts with highly efficient charge separation are of critical significance for improving photocatalytic hydrogen production performance. Herein, a cost-effective and high-performance composite photocatalyst, cobalt-phosphonate-derived defect-rich cobalt pyrophosphate hybrids (CoPPi-M) modified Cd 0.5 Zn 0.5 S is rationally devised via defect and interface engineering, in which the co-catalyst CoPPi-M delivers a strong interaction with host photocatalyst Cd 0.5 Zn 0.5 S, rendering Cd 0.5 Zn 0.5 S/CoPPi-M with a remarkably improved efficiency of charge separation and migration. Besides, Cd 0.5 Zn 0.5 S/CoPPi-M exhibits a hydrophilic surface with ample access to electrons and a strong reduction ability of electrons. Benefiting from these advantages, the integration of defect-rich cobalt pyrophosphate and Cd 0.5 Zn 0.5 S enables Cd 0.5 Zn 0.5 S/CoPPi-M−5% with high photocatalytic H 2 production rate of 6.87 mmol g−1h−1, which is 2.46 times higher than that of pristine Cd 0.5 Zn 0.5 S, and the notable apparent quantum efficiency (AQE) is 20.7% at 420 nm. This work provides a promising route for promoting the photocatalytic performance of non-precious hybrid photocatalyst via defect and interface engineering, and advances energy-generation and environment-restoration devices. [ABSTRACT FROM AUTHOR]

The mesoporous Cd-Zn-S solid solutions (E-Cd x Zn 1-x S) with abundant surface defects synthesized via ingenious inorganic self-template co-precipitation method at room temperature, exhibiting high-efficient activity and stability for photocatalytic hydrogen evolution. The practical application of photocatalytic water splitting for hydrogen evolution hinges on the development of high-efficient and low-cost photocatalysts. Defects engineering has emerged as a promising strategy to enhance photocatalytic activity effectively. Herein, a facile and versatile co-precipitation method is proposed to fabricate mesoporous Cd-Zn-S solid solutions (E-Cd x Zn 1-x S) with abundant surface defects by the inorganic salts formed in the reaction system as self-template. Compared with Cd-Zn-S solid solutions (W-Cd 0.65 Zn 0.35 S) prepared by the traditional co-precipitation method, the enhanced specific surface area and abundant surface defects endow E-Cd 0.65 Zn 0.35 S with more accessible active sites and effective separation of electron-hole pairs for the photocatalytic water splitting reaction. The E-Cd 0.65 Zn 0.35 S solid solution exhibits hydrogen evolution rate of 5.2 mmol h−1 g−1 without loading noble metal as cocatalyst under visible light, which is 1.13 times higher than that of W-Cd 0.65 Zn 0.35 S sample. The present work provides a simple, low-cost and prospective strategy for the synthesis of defective Cd-Zn-S solid solutions, and it also delivers guidance to design and develop the advanced visible-light photocatalyst in the future. [ABSTRACT FROM AUTHOR]

Activated carbons (ACs) were synthesized by a simple pyrolysis of polystyrene sulfonic acid-co-maleic acid sodium salt (PSC) at 800, 850 and 900 °C followed by water washing. The samples were characterized by potentiometric titration, transmission electron microscopy, nitrogen adsorption isotherms, and X-ray photoelectron spectroscopy. A change in a carbonization temperature caused variations in surface areas, pore structures and sulfur/nitrogen contents. During pyrolysis some intrinsic sulfonic acid groups of PSC were decomposed as SO 2 , and some were embedded in the carbon matrix as thiophene sulfur and sulfones. N 2 atmosphere at high temperature with a reducing capability of the carbon surface resulted in an incorporation of nitrogen species to the carbon matrix. ACs had a hierarchical pore structure and the sample at 900 °C (AC-900) had a specific surface area of 960 m2 g−1 with V micro /V total at 0.4. The sample was tested for hydrogen evolution reaction (HER) in 1 M KOH, at the current density of 10 mA cm−2. The overpotential of AC-900 was 450 mV with a Tafel slop of 163.32 mV dec−1. The results suggested an efficient Volmer dynamics process of HER and pyridinc-N were found as contributing to the catalytic activity. Micro and mesoporous carbon was pyrolized with organic salts. The temperature affected surface structure of carbon and functional groups on the surface could be adjusted through controlling the atmosphere and temperature. The hydrogen evolution reaction was improved with the N,S doped carbon. Image 1 • Activated carbon materials of high surface area are synthesized from organic salts. • Pyrolysis converts sulfonic groups into thiophene sulfur. • Pyrolysis in N 2 introduces pyridine groups into the carbon framework. • The surface of carbons pyrolyzed at 900 °C is rich in basic functional groups.. • AC-900 shows a marked catalytic activity in the hydrogen evolution reaction in KOH electrolyte. [ABSTRACT FROM AUTHOR]

The p/n-junction in heteroatoms-doped carbon might be engineered to adjust the population of the charge carriers to perform the oxygen evolution reaction (OER) with holes in a p-type region and hydrogen evolution reaction (HER) with electrons in a n-type region. The carbons (AC) with introduced Fe, Ni and Co species of hierarchical porous structures were derived by pyrolysis of melted poly (styrenesulfonic acid-co-maleic acid) salts. The obtained materials were used as HER, OER and water splitting catalysts. Although all samples were catalytically active, their activity differed depending on the kind of metal. The most promising results were obtained on Ni-AC. An overpotential of Ni-AC to reach 10 mA cm−2 was 259, 382 and 640 mV for HER, OER and water splitting, respectively. Mott-Schottky tests indicated that Ni-AC has p / n -type semiconductor features. While its n -type region was responsible for HER, the p -type region governed OER. A high dispersion of the nickel-based catalytic centers in the hierarchical pore system resulted in an efficient utilization of the active sites for the electron transfer processes. Besides the satisfactory performance, the advantage of the derived catalyst is in its simple synthesis from a commodity polymer. The Ni doped Hierarchical porous carbon was obtained through the melting assisted method. The Ni-AC electrode represented a high stability in HER, OER, and water splitting with a p/n-junction Image 1 • Hierarchical porous carbon was derived from melted polymer salts by pyrolysis. • Highly dispersed transition metals (Ni, Fe and Co) were dispersed within the carbon matrix. • Addition of Ni promoted a high surface area of 832 m2 g-1 with preserved a hierarchical porous structure. • Ni-AC exhibited an overpotential of 640 mV for water splitting due to its p/n -junction. [ABSTRACT FROM AUTHOR]

Abstract Development of high-performance electrocatalysts for overall water splitting is vital for the production of renewable hydrogen energy. Monolithic Ni(OH) 2 nanosheets are fabricated through a facile hydrothermal oxidation procedure of commercial Ni foam. And Ni 2 P, Ni 2 S 3 and NiSe 2 nanosheets are obtained by subsequent low-temperature phosphorization, sulfurization and selenization of the monolithic Ni(OH) 2 nanosheets, respectively. The resultant monolithic materials can be directly employed as self-supported electrodes for efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media, especially, Ni(OH) 2 nanosheets for OER and Ni 2 P nanosheets for HER, respectively, revealing their versatile and practical nature for hydrogen production. Moreover, a well water electrolyzer through a matched electrode pair with Ni(OH) 2 nanosheets as anode and Ni 2 P nanosheets as cathode can achieve a water splitting current density of 10 mA cm−2 at a cell voltage of 1.64 V, and maintains this current density as least 48 h without evident decay in 1.0 mol L−1 KOH electrolyte. These efficient electrocatalysts with a low-cost, facile synthesis procedure and additive-free properties have great potential for emerging realistic energy storage and conversion fields. Graphical abstract A facile strategy was developed for the fabrication of monolithic Ni x M y (M = OH, P, S, Se) nanosheets on Ni foam with integrated configuration. The resultant materials as self-supported electrodes exhibit significant activity and durability for efficient oxygen/hydrogen evolution reactions. Image 1 [ABSTRACT FROM AUTHOR]

Modulating electronic asymmetricity of catalysts is a novel option to regulate the electrocatalytic performance. Nevertheless, the efficient regulation of asymmetric degree of heterostructured catalysts at the atomic level still remains challenging. Herein, Ru nanoclusters (NCs, average particle size of ∼ 1.3 nm) were anchored on carbon materials doped by controllable N functional groups to optimize the electronic asymmetricity toward efficient hydrogen evolution reaction (HER). The electronic interaction between Ru and N species, and hence, the asymmetric electronic distribution of Ru NCs is subjectively manipulated by precisely tailoring the type of N dopants, especially pyrrolic-N, of carbon substrates. As a result, the pyrrolic-N dominated Ru-based heterostructures exhibit excellent HER activity compared to most of the current Ru-based electrocatalysts in basic media. Multiple spectroscopy experiments and density functional theory simulations demonstrate that the asymmetric distribution of surface electron of Ru-based heterostructures not only accelerates H 2 O adsorption and dissociation at interfacial Ru sites with positive charge but also facilitates the adsorption behavior of hydrogen on surface Ru sites with negative charge, thereby simultaneously optimizing the elementary steps in basic HER process. The present findings would provide some crucial understanding in manipulating the local electronic asymmetricity toward reasonable design and fabrication of advanced catalysts and beyond. [Display omitted] • Ru nanoclusters supported on N-doped carbon exhibits high performance for HER. • Electronic asymmetricity of Ru nanoclusters is manipulated by tailoring the type of N dopants. • Electronic asymmetry of Ru nanoclusters facilitates the formation of different active sites towards basic HER. [ABSTRACT FROM AUTHOR]

Nanocarbon is an important metal-free catalyst for various applications including oxidative dehydrogenation and direct dehydrogenation reactions. The surface oxygen-containing groups of nanocarbon are regarded as active sites in oxidative dehydrogenation reaction. However, the active sites for direct dehydrogenation are still not totally clear. Herein, multiwall carbon nanotubes (MWCNTs) are activated by different oxidation processes and thermal treatments, and used as effective catalysts for direct dehydrogenation of propane to propylene. The physicochemical properties of the oxidized MWCNTs are characterized by SEM, TEM, XRD, N 2 sorption, Raman, TGA, TPD-MS and XPS techniques. It is revealed that the concentrations of the oxygen-containing groups could be well controlled by sequential acid oxidation and thermal treatment. The activities of these nanocarbon catalysts exhibit a good linear dependence on the number of carbonyl/quinone groups, confirming the active sites are C O groups on the surface of the MWCNTs. [ABSTRACT FROM AUTHOR]

The rapid growth of environment pressures and fast depletion of fossil fuels compel public to pay more attention on developing affordable and efficient catalysts for renewable energy production. Metal (Co, Fe, Ni, etc.) phosphide nanoparticles uniformly encapsulated in porous N,P-codoped nanofibrous carbon coated on carbon paper (MeP@NPC/CP) are prepared through one-pot carbonization-phosphorization strategy, which are potential for effective electrocatalytic water reduction/oxidation reactions. The well-designed self-supported structure and the abundant accessible active centers together contribute to the high electrocatalytic performance for hydrogen and oxygen evolution. Remarkably, an alkaline electrolyzer assembled from CoP@NPC/CP as cathode and anode can afford the current density of 10 mA cm −2 at the voltage of 1.67 V for overall water splitting in alkaline media with excellent stability. The easily prepared route with suitable structural and textural properties endows this self-supported materials with versatile function as abundant metal catalysts for realistic energy conversion and storage systems. [ABSTRACT FROM AUTHOR]

Engineering active and robust catalysts for hydrogen evolution and oxidation reactions (HER and HOR) are of importance for the realization of green hydrogen economy. To make catalysts economically competitive for large−scale applications, even−increasing interests have been shifted to designing nonprecious materials for HER and HOR with active and robust performance. Herein, with the guidance of interface engineering, the monolithic catalyst of Ni−MoO 2 heterojunctions on nickel foam (Ni−MoO 2 /NF) was deliberately fabricated by the in−situ corrosion−growth under hydrothermal condition and following thermal−reduction procedure, which exhibits extraordinary HER and HOR performance, for instance, nearly Pt−like catalytic activities, robust long−term durability even under large current density, and superior Faradaic efficiency in alkaline electrolyte. Coupling with the active urea oxidation catalyst of NiMoO 4 /NF as anode (treating the hydrothermal product in Ar atmosphere), the assembled overall urea splitting electrolyzer with Ni−MoO 2 /NF as cathode affords the lower voltage of 1.53 V at 20 mA cm−2, and keeps this performance overall 120 h without decay. The systematic physicochemical characterization and electrochemical investigations reveal that the heterointerface-induced charge redistribution, individual electrocatalytic functions, superaerophobic/superhydrophilic electrode surface, and monolithic electrode structure together collaborate to the efficient catalytic activity and stability under larger current density. [Display omitted] • Ni-MoO 2 heterostructures and NiMoO 4 octahedron as monolith electrodes are synthesized and scaled up. • Charges directly transfer from the nickel foam substrate to catalysts in the monolith electrodes. • Catalysts bonded to the substrates give excellent mechanical stability to withstand large current densities. • Overall urea splitting electrolyzer with Ni-MoO 2 cathode and NiMoO 4 anode exhibits great energy efficiency. [ABSTRACT FROM AUTHOR]

The construction of S-scheme heterojunction catalysts is promising for efficient photocatalytic hydrogen production, but the conscious modulation of S-scheme charge transfer has remained largely underdeveloped. Herein, P and C modified Co 2 P/black TiO 2 S-scheme heterojunction photocatalyst (Co 2 P/PC- b -TiO 2) is prepared by pyrolyzing a mixture of cobalt phosphonate and TiO 2 under H 2 atmosphere. The in situ formed P and C dopants can not only enhance the ratio of surface active O species to bulk O defects but also inhibit anatase-to-rutile phase transformation, thereby ensuring the high intrinsic activity. More importantly, the S-scheme heterojunction between PC- b -TiO 2 and Co 2 P is modified by the incorporation of P and C, wherein the intimately coupled heterointerface and strong internal electric field can accelerate charge separation and migration and optimize the available redox potential. Accordingly, Co 2 P/PC- b -TiO 2 displays dramatically ascendant photocatalytic hydrogen evolution performance and outstanding stability. This study provides guidance for elaborately modifying S-scheme heterojunctions through heteroatom doping and heralds a new paradigm for engineering advanced heterojunction catalysts. [Display omitted] • S-scheme heterojunction modification strategy is performed on P,C-dual-doped Co 2 P/black TiO 2. • P and C dopants create high intrinsic activity, intimate heterointerface and strong internal electric field. • Modified S-scheme heterojunction accelerates charge separation and migration and optimizes available redox potential. • Co 2 P/PC- b -TiO 2 displays dramatically ascendant photocatalytic hydrogen evolution performance. [ABSTRACT FROM AUTHOR]

FeNiP nanoparticles dispersed on carbon nanosheets were fabricated by direct pyrolysis, which achieved the improved electrochemical activities through optimizing Fe/Ni ratio. • FeNiP nanoparticles dispersed on N,P-doped carbon nanosheets fabricated by a facile method. • The electrochemical activity of the FeNiP/NPCS improved through optimizing Fe/Ni ratio. • High electrocatalytic activity and stability for HER, OER, and ORR. • High performance for overall water splitting and rechargeable Zn-air batteries. Hybridization of non-precious metals with advanced carbon monolith provides a promising approach to substitute noble metal catalysts for various electrochemical reactions. The structural and electronic properties of non-precious metals significantly affect electrocatalytic performance, which depends on the physicochemical structure of carbon substrates and the types of metal components. Herein, binary FeNi phosphide nanoparticles coupled with N,P-modified carbon nanosheets were fabricated through an universal carbonization-phosphorization approach. Besides the structural advantage of 2D nanosheets, the electronic structure change of bimetallic FeNi phosphides via modulating Fe/Ni ratio is another reason responded for the exceptional activities with reduced overpotentials of this hybridized catalyst for both hydrogen evolution, oxygen evolution and oxygen reduction reactions. Furthermore, by employing the fabricated materials as electrode catalysts for overall water splitting and rechargeable Zn-air batteries with liquid and solid-state electrolytes, excellent performances are achieved in these energy conversion and storage devices, revealing the significant feasibility for practical applications. [ABSTRACT FROM AUTHOR]