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[Display omitted] 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. [ABSTRACT FROM AUTHOR]

[Display omitted] 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. [ABSTRACT FROM AUTHOR]

[Display omitted] 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. [ABSTRACT FROM AUTHOR]

[Display omitted] 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. [ABSTRACT FROM AUTHOR]

[Display omitted] 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. [ABSTRACT FROM AUTHOR]

[Display omitted] 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. [ABSTRACT FROM AUTHOR]

The hierarchical carbon-encapsulated yolk-shell nickelic composites were fabricated by a general MOF-derived route via Ostwald ripening and anion exchange strategy. Benefitting from the unique yolk-shell carbon framework, synergistic effect and satisfied phys-chemical characters, the nickel phosphide displays superior sodium storage properties compared with sulfide and selenide counterparts. [Display omitted] 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. [ABSTRACT FROM AUTHOR]

• MoP particles were uniformly dispersed on the MoO 3 nanowires by the phosphorization method. • Various percentage of MoP particles loading was regulated by different phosphorous precursor. • Enhanced selective photocatalytic oxidation of benzyl alcohol to benzaldehyde performance was achieved. • Enhanced selective photocatalytic performance can be owing to synergistic effect. The selective oxidation of small molecules to high-value-added products is regarded as a promising approach to alleviating the worldwide energy crisis. In this work, heterogenous non-noble-metal molybdenum(III) phosphide (MoP) catalysts were anchored onto MoO 3−x nanowires (MoP@MoO 3−x) via a facile phosphorization method using various amounts of phosphorus precursor. Because of the combined attributes of the MoP and the MoO 3−x nanowires, the novel MoP@MoO 3−x nanowire catalysts not only provide more active sites but also enhance electron–hole separation efficiency. The results show that the selective transformation of benzyl alcohol to benzaldehyde was achieved with 67% selectivity. A comprehensive study including field-emission transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, Brunauer–Emmett–Teller analysis, X-ray diffraction analysis, UV–vis diffuse reflectance spectrum, electron-spin resonance, photocurrent measurements, electrochemical impedance spectroscopy, and density functional theory (DFT) computations was conducted. The selective photocatalytic oxidation results and the DFT calculations indicate that the MoP particles anchored onto the MoO 3−x substrate display an important role in enhancing the selective photocatalytic oxidation of benzyl alcohol. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Two charge transfer pathways of interface coupling and shallow traps. • We prepared P-doped In 2 S 3 nanosheets with an amorphous InPO x shell on FTO. • The photocurrent density increased 15-times compared with pristine In 2 S 3 nanosheets. • Two charge transfer pathways of interface coupling and shallow traps were proposed. • The prepared photoanode showed very favorable stability on a layer of TiO 2. Photoelectrochemical (PEC) water splitting via semiconductors is an effective and feasible method for synthesizing renewable hydrogen (H 2) fuels. In this study, β-In 2 S 3 nanosheets were first grown on conductive glass. Then, we prepared P-doped β-In 2 S 3 nanosheets with an amorphous InPO x overlayer via the incomplete phosphorization of pristine β-In 2 S 3 nanosheets. When we used this material as photoanode in a PEC cell for water splitting, the photocurrent density drastically increased to 2.2 mA cm−2 at 1.23 V versus a reversible hydrogen electrode (vs. RHE). It enhanced 15 times as the pristine β-In 2 S 3 nanosheets, which was only 0.15 mA cm−2 at 1.23 V vs. RHE (solar standard spectrum, 100 mW cm−2). The photoelectric conversion efficiency as high as 0.65% at a low potential of 0.81 V vs. RHE was achieved for the phosphorized β-In 2 S 3 nanosheets. A series of experiments proved that the P-doping accelerated semiconductor charge-transport and the InPO x overlayer played cocatalyst role. We penetratingly investigated the pathway of charge transfer via femtosecond transient absorption. The results showed one pathway of charge transfer in pristine β-In 2 S 3 photoanode. However, there were two pathways (core/shell coupling and shallow trap states) for charge transfer in the phosphorized β-In 2 S 3 photoanode, which improved the performance of its PEC water oxidation. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract 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. [ABSTRACT FROM AUTHOR]