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Oxygen evolution reaction (OER) process is the "bottleneck" of water splitting, and the low-cost and high-efficient OER catalysts are of great importance and attractive but they are still challenging. Herein, a dual modification strategy is developed to tune and enrich the structure of cobalt silicate (Co 2 SiO 4 ) showing boosted OER properties. Cobalt oxide (Co 3 O 4 ) decorated Co 2 SiO 4 nanobelts, denoted as CS, is firstly prepared using a Co-based precursor by a facile hydrothermal reaction. Then, cobalt phosphide (CoP) nanoparticles are in-situ grown on CS (denoted as CS-P) by the phosphorization process, which provide many active sites and boost the surface reactivity. The experimental results and density function theory (DFT) calculations both reveal that the CoP on CS can improve the conductivity and ensure fast kinetics, thus leading to boost the OER properties of Co 2 SiO 4 . When the phosphorization temperature is at 400 °C (CS-P400), it gains the lowest overpotential of 297 mV, which is much lower than CS (340 mV) and Co 2 SiO 4 (409 mV) at 10 mA·cm -2 , and even superior to the state-of-the-art transition metal silicates. CS-P400 also achieves high electrochemical active surface area (ECSA) and small Tafel slope owing to its porous structures with large specific surface area and nanosheet-like structures which are good for exposing many active sites and favorable to the fast kinetics. This work not only provides a dual modification route to boost catalytic activity of Co 2 SiO 4 (CS-P400), but also sheds light on a new avenue for developing highly dispersed CoP on silicates to boost OER performances., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Developing effective and long-lasting electrocatalysts for oxygen evolution reaction (OER) is critical for increasing sustainable hydrogen production. This paper describes the production and characterization of CoFeP nanoparticles (CFP NPs) as high-performance electrocatalysts for OER. The CFP NPs were produced using a simple hydrothermal technique followed by phosphorization, yielding an amorphous/crystalline composite structure with improved electrochemical characteristics. Our results reveal that CFP NPs have a surprisingly low overpotential of 284 mV at a current density of 100 mA cm -2 , greatly exceeding the precursor CoFe oxide/hydroxide (CFO NPs) and the commercial RuO 2 catalyst. Furthermore, CFP NPs demonstrate exceptional stability, retaining a constant performance after 70 h of continuous operation. Post-OER characterization analysis revealed transformations in the catalyst, including the formation of cobalt-iron oxides/oxyhydroxides. Despite these changes, CFP NPs showed superior long-term stability compared to native metal oxides/oxyhydroxides, likely due to enhanced surface roughness and increased active sites. This study proposes a viable strategy for designing low-cost, non-precious metal-based OER catalysts, which will help advance sustainable energy technology.

The sluggish kinetics of oxygen reduction reactions (ORRs) require considerable Pd in the cathode, hindering the widespread of alkaline fuel cells (AFCs). By alloying Pd with transition metals, the oxygen reduction reaction's catalytic properties can be substantially enhanced. Nevertheless, the utilization of Pd-transition metal alloys in fuel cells is significantly constrained by their inadequate long-term durability due to the propensity of transition metals to leach. In this study, a nonmetallic doping strategy was devised and implemented to produce a Pd catalyst doped with P that exhibited exceptional durability towards ORRs. Pd 3 P 0.95 with an average size of 6.41 nm was synthesized by the heat-treatment phosphorization of Pd nanoparticles followed by acid etching. After P-doping, the size of the Pd nanoparticles increased from 5.37 nm to 6.41 nm, and the initial mass activity (MA) of Pd 3 P 0.95 /NC reached 0.175 A mg Pd -1 at 0.9 V, slightly lower than that of Pd/C. However, after 40,000 cycles of accelerated durability testing, instead of decreasing, the MA of Pd 3 P 0.95 /NC increased by 6.3% while the MA loss of Pd/C was 38.3%. The durability was primarily ascribed to the electronic structure effect and the aggregation resistance of the Pd nanoparticles. This research also establishes a foundation for the development of Pd-based ORR catalysts and offers a direction for the future advancement of catalysts designed for practical applications in AFCs.

Non-precious metals have shown attractive catalytic prospects in hydrogen production from ammonia borane hydrolysis. However, the sluggish reaction kinetics in the hydrolysis process remains a challenge. Herein, P-bridged Fe-X-Co coupled sites in hollow carbon spheres (Fe-CoP@C) has been synthesized through in situ template solvothermal and subsequent surface-phosphorization. Benefiting from the optimized electronic structure induced by Fe doping to enhance the specific activity of Co sites, bimetallic synergy and hollow structure, the as-prepared Fe-CoP@C exhibits superior performances with a turnover frequency (TOF) of 183.5 min -1 , and stability of over 5 cycles for ammonia borane hydrolysis, comparable to noble metal catalysts. Theoretical calculations reveal that the P-bridged Fe-X-Co coupled sites on the Fe-CoP@C catalyst surfaces is beneficial to adsorb reactant molecules and reduce their reaction barrier. This strategy of constructing hollow P-bridged bimetallic coupled sites may open new avenues for non-precious metal catalysis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

In this study, the successful synthesis of bimetallic nickel/cobalt phosphide nanosheets (Ni-Co-P NSs) via the hydrothermal method and the subsequent high-temperature phosphorization process were both confirmed. Ni-Co-P NSs exhibited excellent electrocatalytic activity for the electrochemical non-enzymatic DA sensing. The surface morphologies and physicochemical properties of Ni-Co-P NSs were characterized by atomic force microscopy (AFM), field-emission scanning (FESEM), field-emission transmission electron microscopy (FETEM), and X-ray diffraction (XRD). Further, the electrochemical performance was evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The metallic nature of phosphide and the synergistic effect of Ni/Co atoms in Ni-Co-P NSs provided abundant catalytic active sites for the electrochemical redox reaction of DA, which exhibited a remarkable consequence with a wide linear range from 0.3~50 μM, a high sensitivity of 2.033 µA µM -1 cm -2 , a low limit of detection of 0.016 µM, and anti-interference ability. As a result, the proposed Ni-Co-P NSs can be considered an ideal electrode material for the electrochemical non-enzymatic DA sensing.

The electronic properties and structural characteristics of transition metal materials have a significant impact on their electrocatalytic performance. Therefore, precisely controlling the electronic states of core metals and fabricating catalysts with advanced structures are conducive to facilitating electrolysis process. Herein, we manipulate the electronic properties of the electroactive sites of catalysts by controlling the degree of phosphorization during the phosphorization process. The Co x P-FeP@C electrocatalysts, characterized by their sea-urchin morphology, were synthesized by subjecting CoFc-metal organic framework (MOF) precursors to phosphorization for specific time intervals. The optimized Co 2 P-FeP@C-5 electrocatalyst showed the optimum performance towards the oxygen evolution reaction (OER) catalytic efficiency with 239 mV overpotential and the hydrogen evolution reaction (HER) activity with 169 mV overpotential to reach 10 mA·cm -2 in 1.0 M KOH (PH = 13.8). For comparison, the extended duration of phosphorization resulted in the formation of CoP-FeP@C-15 and CoP-FeP@C-30 electrocatalysts, which exhibited compromised electrocatalytic performance due to the transformation of the electroactive core Co 2 P to CoP during subsequent phosphorization processes. The improved interfacial properties between Co 2 P and FeP play a crucial role in enhancing the efficiency of water decomposition, attributed to the higher density of states (DOS) at the Fermi Level and the increased availability of electroactive sites for the adsorption of intermediates and electrolysis. These findings are substantiated by density functional theory (DFT) calculations. This approach offers a highly effective means of manipulating the electronic properties of the electroactive transition metal core by controlling the degree of phosphorization, with the ultimate goal of achieving efficient water splitting., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Oxygen Evolution Reaction (OER) has gained significant attention due to its crucial role in renewable energy systems. The quest for efficient and low-cost OER catalysts remains a challenge of significant interest and importance. In this work, phosphate-incorporated cobalt silicate hydroxide (denoted as CoSi-P) is reported as a potential electrocatalyst for OER. The researchers first synthesized hollow spheres of cobalt silicate hydroxide Co 3 (Si 2 O 5 ) 2 (OH) 2 (denoted as CoSi) using SiO 2 spheres as a template through a facile hydrothermal method. Phosphate (PO 4 3- ) was then introduced to layered CoSi, leading to the reconstruction of the hollow spheres into sheet-like architectures. As expected, the resulting CoSi-P electrocatalyst demonstrated low overpotential (309 mV at 10 mA·cm -2 ), large electrochemical active surface area (ECSA), and low Tafel slope. These parameters outperform CoSi hollow spheres and cobaltous phosphate (denoted as CoPO). Moreover, the catalytic performance achieved at 10 mA cm -2 is comparable or even better than that of most transition metal silicates/oxides/hydroxides. The findings indicate that the incorporation of phosphate into the structure of CoSi can enhance its OER performance. This study not only provides a non-noble metal catalyst CoSi-P but also demonstrates that the incorporation of phosphates into transition metal silicates (TMSs) offers a promising strategy for the design of robust, high-efficiency, and low-cost OER catalysts., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Oxygen doping strategy is one of the most effective methods to improve the electrochemical properties of nickel-cobalt phosphide (NiCoP)-based capacitors by adjusting its inherent electronic structure. In this paper, O-doped NiCoP microspheres derived from porous nanostructured nickel metal-organic frameworks (Ni-MOFs) were constructed through solvothermal method followed by phosphorization treatment. The O-doping concentration has a siginificant influence on the rate performance and cycle stability. The optimized O-doped NiCoP electrode material shows a specific capacitance of 632.4 F-g -1 at 1 A-g -1 and a high retention rate of 56.9% at 20 A g -1 . The corresponding NiCoP-based asymmetric supercapacitor exhibits a high energy density of 30.1 Wh kg -1 when the power density is 800.9 W kg -1 , and can still maintain 82.1% of the initial capacity after 10 000 cycles at 5 A g -1 ., (© 2023 IOP Publishing Ltd.)

Electronic regulation via interface engineering is recognized as an attractive strategy for boosting electrocatalytic activity. In this work, a self-supported heterostructure electrocatalyst is explored by a feasible hydrothermal-pyrolysis strategy, in which Ni 2 P nanoparticles are anchored on NiMoP 2 nanosheet arrays grown on carbon cloth (Ni 2 P/NiMoP 2 /CC). Benefitting from the nanosheet array architecture and the synergy effect between the Ni 2 P and NiMoP 2 , the as-prepared Ni 2 P/NiMoP 2 /CC manifests highly efficient activity and stability toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Density functional theory calculations further indicates that the heterointerface in Ni 2 P/NiMoP 2 /CC enable optimized interface electron structure and reduce the activation barriers for intermediates, improving the intrinsic electrocatalytic activity. Remarkably, the Ni 2 P/NiMoP 2 /CC||Ni 2 P/NiMoP 2 /CC electrolyzer affords 10 mA cm -2 at a low voltage of 1.59 V, outperforming its monometallic phosphides counterparts and most of transition metal-based bifunctional electrocatalysts. The electrolyser was powered by a solar cell to produce H 2 and O 2 simultaneously, indicating its potential application in solar-to-hydrogen conversion., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

NiCoP nanosheets (NSs) were successfully synthesized using the hydrothermal and high-temperature phosphorization process. The obtained NiCoP NSs were immobilized on a glassy carbon electrode (GCE) and used to construct a novel sensing platform for electrochemical non-enzymatic H 2 O 2 sensing. Physicochemical characteristics of NiCoP NSs were obtained by field-emission scanning electron microscopy (FESEM), field-emission transmission electron microscope (FETEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In addition, the electrochemical properties of NiCoP NSs were obtained by cyclic voltammetry (CV) and chronoamperometry (CA) towards the non-enzymatic detection of H 2 O 2 . FESEM and FETEM images provided a morphological insight (the unique nanosheets morphology of NiCoP) that could expose more active sites to promote mass/charge transport at the electrode/electrolyte interface. XRD and XPS results also confirmed the crystalline nature of the NiCoP nanosheets and the coexistence of multiple transitional metal oxidation states in NiCoP nanosheets. These unique physicochemical characteristics had a degree of contribution to ensuring enhancement in the electrochemical behavior. As a result, the synthesized NiCoP NSs composed of intercalated nanosheets, as well as the synergistic interaction between bimetallic Ni/Co and P atoms exhibited excellent electrocatalytical activity towards H 2 O 2 electroreduction at neutral medium. As the results showed, the electrochemical sensing based on NiCoP NSs displayed a linear range of 0.05~4 mM, a sensitivity of 225.7 μA mM -1 cm -2 , a limit of detection (LOD) of 1.190 μM, and good selectivity. It was concluded that NiCoP NSs-based electrochemical sensing might open new opportunities for future construction of H 2 O 2 sensing platforms.

Designing non-precious electrocatalysts with multiple active centers and durability toward overall water splitting is of great significance for storing renewable energy. This study reports a low-cost Mo, Fe codoped NiCoP x electrocatalysts derived from Co-Fe Prussian blue analogue and following phosphorization process. Benefitted from the optimized electronic configuration, hierarchical structure and abundant active sites, the Mo,Fe-NiCoP x /NF electrode has shown competitive oxygen evolution reaction (ƞ 10  = 197 mV) and hydrogen evolution reaction performance (ƞ 10  = 99 mV) when the current density is 10 mA cm -2 in 1 M KOH solution. Moreover, the integrated water splitting device assembled by Mo,Fe-NiCoP x /NF as both anode and cathode only needs a voltage of 1.545 V to reach 10 mA cm -2 . Density functional theory results further confirm that the Mo, Fe codoped heterostructure can synergistically optimize the d-band center and Gibbs free energy during electrocatalytic processes, thus accelerating the kinetics of electrochemical water splitting. This work demonstrates the importance of rational combination of metal doping and interface engineering for advanced catalytic materials., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Inc.)

Transition-metal compounds have attracted enormous attention as potential energy storage materials for their high theoretical capacity and energy density. However, the most present transition-metal compounds still suffer from severe capacity decay and limited rate capability due to the lack of robust architectures. Herein, a general metal-organic framework-derived route is reported to fabricate hierarchical carbon-encapsulated yolk-shell nickelic spheres as anode materials for sodium-ion batteries. The nickelic metal-organic framework (Ni-MOF) precursors can be in situ converted into hierarchical carbon-encapsulated Ni 2 P (Ni 2 P/C), NiS 2 (NiS 2 /C) and NiSe 2 (NiSe 2 /C) by phosphorization, sulfuration, and selenation reaction, respectively, and maintain their yolk-shell sphere-like morphology. The as-synthesized Ni 2 P/C sample can deliver much lower polarization and discharge platform, smaller voltage gap, and faster kinetics in comparison with that of the other two counterparts, and thus achieve higher initial specific capacity (3222.1/1979.3 mAh g -1 ) and reversible capacity of 765.4 mAh g -1 after 110 cycles. This work should provide new insights into the phase and structure engineering of carbon-encapsulated transition-metal compound electrodes via MOFs template for advanced battery systems., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

3D porous Ni is fabricated via an easily scalable electroless plating method using a dynamic template formed through in-situ hydrogen bubbles. The pore size in the range of several micrometers is controllable through adjusting the Ni 2+ depositing rate and hydrogen bubbles releasing rate. The Ni 3 S 2 nanosheet arrays anode is then grown on the unique 3D porous Ni current collector followed by subsequent surface phosphorization. The tremendous interconnected pores and rich voids between the Ni 3 S 2 nanosheet arrays cannot only provide rapid transferring channels for Na + , but also accommodate volumetric changes of the Ni 3 S 2 electrode during cycling, guaranteeing the integrity of the active material. In addition, the surface phosphorized layer enhances the electronic conductivity through providing an electron transport highway along the 3D Ni 3 S 2 , NiP 2 layer, and 3D porous Ni current collector, and simultaneously stabilizes the electrode/electrolyte interphase as a protecting layer. Because of these merits, the phosphorized 3D porous Ni 3 S 2 (3D P-Ni 3 S 2 ) electrode is capable of delivering an ultra-stable capacity of 387.5 mAh g -1 at 0.1 A g -1 , and a high capacity retention of 85.3% even at a high current density of 1.6 A g -1 ., (© 2021 Wiley-VCH GmbH.)

Exploring earth-abundant electrocatalysts with excellent activity, robust stability, and multiple functions is crucial for electrolytic hydrogen generation. Porous phosphorized CoNi 2 S 4 yolk-shell spheres (P-CoNi 2 S 4 YSSs) were rationally designed and synthesized by a combined hydrothermal sulfidation and gas-phase phosphorization strategy. Benefiting from the strengthened Ni 3+ /Ni 2+ couple, enhanced electronic conductivity, and hollow structure, the P-CoNi 2 S 4 YSSs exhibit excellent activity and durability towards hydrogen/oxygen evolution and urea oxidation reactions in alkaline solution, affording low potentials of -0.135 V, 1.512 V, and 1.306 V (versus reversible hydrogen electrode) at 10 mA cm -2 , respectively. Remarkably, when used as the anode and cathode simultaneously, the P-CoNi 2 S 4 catalyst merely requires a cell voltage of 1.544 V in water splitting and 1.402 V in urea electrolysis to attain 10 mA cm -2 with excellent durability for 100 h, outperforming most of the reported nickel-based sulfides and even noble-metal-based electrocatalysts. This work promotes the application of sulfides in electrochemical hydrogen production and provides a feasible approach for urea-rich wastewater treatment., (© 2021 Wiley-VCH GmbH.)

Design and develop of cost-effective non-enzymatic electrode materials is of great importance for next generation of glucose sensors. In this work, we report a high-performance self-supporting electrode fabricated via direct epitaxial growth of nickel phosphide on Ni foam (Ni 2 P/NF) for nonenzymatic glucose sensors in alkaline solution. Under the optimal conditions, the uniform Ni 2 P nanosheets could be obtained with an average thickness of 80 nm, which provides sufficient active sites for glucose molecules. As a consequence, the Ni 2 P/NF electrode displays superior electrochemistry performances with a high sensitivity of 6375.1 μ A mM -1 cm -2 , a quick response about 1 s, a low detection limit of 0.14 μ M (S/N = 3), and good selectivity and specificity. Benefit from the strong interaction between Ni 2 P and NF, the Ni 2 P/NF electrode is also highly stable for long-term applications. Furthermore, the Ni 2 P/NF electrode is capable of analyzing glucose in human blood serum with satisfactory results, indicating that the Ni 2 P/NF is a potential candidate for glucose sensing in real life., (© 2021 IOP Publishing Ltd.)

Efficient and durable electrocatalysts are highly desirable for overall water splitting. Herein, a facile strategy is demonstrated to rationally construct CoFe Prussian blue analogues (PBA)@CoP cube-on-sheet hierarchical structure by etching reaction with intermediated CoO to form PBA nanocubes. Benefitting from the heterostructured engineering, the as-synthesized CoFe PBA@CoP presents remarkable electrocatalytic performance in 1.0 m KOH, only requiring overpotentials of 100 mV for hydrogen evolution reaction (HER) and 171 mV for oxygen evolution reaction (OER) to reach the 10 mA cm -2 current density with good stability. Extraordinarily enhanced electrocatalytic performance is ascribed to not only the rapid charge transfer of active species, but also the synergistic effect between each component to achieve tuned electronic structure and abundant electrocatalytic active sites. Especially, the assembled two-electrode cell using CoFe PBA@CoP as both cathode and anode delivers the current densities of 10 mA cm -2 at a relatively low cell voltage of 1.542 V, outperforming most of low-cost bifunctional electrocatalysts reported to date. The controllable and versatile strategy will open up an avenue to prepare hybrid films for advanced electrochemical energy storage and conversion., (© 2021 Wiley-VCH GmbH.)

Developing cost-effectiveness and superior electrocatalysts is crucial to improve the efficiency of oxygen evolution reaction (OER) in water splitting system. Hence, flower-like phosphorus doped Ni 3 S 2 /CoFe 2 O 4 arrays (P-Ni 3 S 2 /CoFe 2 O 4 /NF) were generated on three-dimensional (3D) nickel foam (NF) via the two-step hydrothermal treatment and subsequent phosphorization. Additionally, a series of control experiments were conducted to investigate the formation mechanism. By virtue of the unique 3D configurations and multi-compositions, the as-prepared catalyst exhibited greatly improved OER performance in 1.0 M KOH solution, with the overpotential of only 254 mV at 50 mA cm -2 and low Tafel slope of 54.43 mV dec -1 . This study provides a feasible approach for preparing advanced electrocatalyst in energy conversion and storage devices., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

To solve energy-related environmental problems and the energy crisis, efficient electrochemical materials have been developed as alternative energy storage and conversion systems. Abundant transition metals and their sulfides are attractive electrochemical materials. Herein, we report an efficient phosphorization strategy, which improves the overall electrochemical performance of metal sulfides. In detail, CoS hexagonal bipyramids were synthesized through simple calcination combined with in situ sulfurization of a cobalt-based metal-organic framework template, and then phosphate ion-functionalized CoS (P-CoS) was prepared through a phosphorization reaction. P-CoS exhibited outstanding electrochemical activity as both supercapacitor electrode and oxygen evolution reaction (OER) catalyst. Supercapacitors based on CoS and P-CoS as the electrodes had high specific capacitances of 304 and 442 F g -1 , respectively, and remained stable for over 10 000 cycles at 5 A g -1 . For OER, P-CoS showed a current density of 10 mA cm -2 at an overpotential of 340 mV, with a small Tafel slope. In conclusion, functionalizing CoS with phosphate ions is a promising method for enhancing chemical reactivity and accelerating ion and electron transfer., (© 2020 Wiley-VCH GmbH.)

Exploring low-cost and outstanding bimetallic phosphides to substitute noble metals as electrocatalysts for oxygen evolution reaction (OER) in alkaline media is essential for renewable energy technologies. Herein, bimetallic nickel-iron phosphides nanoparticles (P-NiFe-800 NPs) with rich defects have been synthesized through gas annealing at 800 °C and phosphorization using uniform nickel-iron nanocubes (NiFe NCs) as precursor. At optimized calcination temperature, the obtained P-NiFe-800 NPs are composed of uniform nanoparticles with the rough surface, which suggests the larger surface area and more exposed rich active sites than other samples for OER. The introduction of P element to binary nickel-iron metals can optimize the crystalline and electronic structures of NiFe NCs and thus enhance electrocatalytic properties. Owing to the distinct morphological structure and synergistic effect between nickel-iron and phosphorus, P-NiFe-800 NPs demonstrate superior electrocatalytic activities for OER with lower overpotential of 270.1 mV to achieve a current density of 10 mA cm -2 , smaller Tafel slope of 39 mV dec -1 , lower electrochemical impedance spectroscopy (EIS) value, bigger determined double-layer capacitance (C dl ) of 2130 uF cm -2 and prominent stability than NiFe NCs, NiFe-600 NPs, NiFe-700 NPs, NiFe-800 NPs, NiFe-900 NPs, P-NiFe NCs, P-NiFe-600 NPs, P-NiFe-700 NPs and P-NiFe-900 NPs. The optimized phosphorization is helpful for fabricating the bimetallic phosphides as efficient catalysts for OER., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Application of transition metal phosphides (TMPs) for electrochemical energy conversion and storage has great potential to alleviate the energy crisis. Although there are many methods to get TMPs, it is still immensely challenging to fabricate hierarchical porous TMPs with superior electrochemical performances by a simple, green, and secure approach. Herein, we report a facile method to synthesize the CoP/C nanoboxes by pyrolysis of phytic acid (PA) cross-linked Co complexes that are acquired from reaction of PA and ZIF-67. The PA can not only slowly etch ZIF-67 and gain a hollow structure but also act as a source of phosphorus to prepare CoP/C nanoboxes. The CoP/C nanoboxes deliver an ultrahigh specific capacity (868 mA h g -1 at 100 mA g -1 ) and excellent cycle stability (523 mA h g -1 after 1000 cycles at 500 mA h g -1 ) when used as anode materials for lithium-ion batteries. Moreover, when used as an electrocatalyst for hydrogen evolution reaction, the CoP/C nanoboxes exhibit ultralow overpotential, small Tafel slope, and excellent durability in acidic media. The method to produce CoP/C nanoboxes is easy and environmentally friendly and can be readily extended to design other TMPs/C nanocomposites.

A novel oxygen evolution reaction (OER) catalyst (3 D S235-P steel) based on a steel S235 substrate was successfully prepared by facile one-step surface modification. The standard carbon-manganese steel was phosphorized superficially, which led to the formation of a unique 3 D interconnected nanoporous surface with a high specific area that facilitated the electrocatalytically initiated oxygen evolution reaction. The prepared 3 D S235-P steel exhibited enhanced electrocatalytic OER activities in the alkaline regime, as confirmed by a low overpotential (326 mV at a 10 mA cm -2 ) and a small Tafel slope of 68.7 mV dec -1 . Moreover, the catalyst was found to be stable under long-term usage conditions, functioning as an oxygen-evolving electrode at pH 13, as evidenced by the sufficient charge-to-oxygen conversion rate (faradaic efficiency: 82.11 and 88.34 % at 10 and 5 mA cm -2 , respectively). In addition, it turned out that the chosen surface modification delivered steel S235 as an OER electrocatalyst that was stable under neutral pH conditions. Our investigation revealed that the high catalytic activities likely stemmed from the generated Fe/(Mn) hydroxide/oxohydroxides generated during the OER process. Phosphorization treatment therefore not only is an efficient way to optimize the electrocatalytic performance of standard carbon-manganese steel but also enables for the development of low-costing and abundant steels in the field of energy conversion., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)