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[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] 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]

Platinum‐based catalysts play an outstanding role in alkaline hydrogen evolution reaction (HER) but with sluggish reaction kinetics. Herein, stimulated pH‐dependence phosphorus‐embedded PtNi nano‐alloy clusters (P@PtNi/C) with good alkaline HER catalytic activity are obtained. The overpotential of P@PtNi/C at a current density of 10 mA cm−2 is 26 mV in 1M KOH solution. At the overpotential of 70 mV, the mass activity of P@PtNi/C is 4.62 A mgPt−1, which is 21 times that of commercial 20 wt% Pt/C in terms of the unit mass of Pt. Due to the doping of P elements, the electronic interface is optimized, which enhances the OH− sensitivity and enables more OHad* to be involved in the overall alkaline cathode reaction. Density functional theory calculations suggest that PtNi3P/C can promote the further reduction of OHad* to generate Oad*, which plays an important role in the decomposition of H2O* to form OHad*. A closed‐looping H2O reduction process that exhibits the pH‐dependent characteristics of alkaline HER is proposed. OH− is appropriately integrated into the alkaline HER catalytic process based on P@PtNi/C catalyst, which provides a feasible consideration for the design of alkaline HER catalyst. [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]

Exploring earth‐abundant electrocatalysts with excellent activity, robust stability, and multiple functions is crucial for electrolytic hydrogen generation. Porous phosphorized CoNi2S4 yolk‐shell spheres (P‐CoNi2S4 YSSs) were rationally designed and synthesized by a combined hydrothermal sulfidation and gas‐phase phosphorization strategy. Benefiting from the strengthened Ni3+/Ni2+ couple, enhanced electronic conductivity, and hollow structure, the P‐CoNi2S4 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‐CoNi2S4 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. [ABSTRACT FROM AUTHOR]

Using low cost and high efficiency non-precious bimetallic phosphosulphide as electrocatalyst for hydrogen evolution reaction (HER) is not only convenient but also environment-friendly for industrial production. Therefore, we propose a simple and efficient method to prepare a series of Cu-doped bimetallic phosphosulphide nanosheet arrays on nickel foam (CuNiS@Ni 2 P/NF). The CuNiS@Ni 2 P/NF exhibits the superior HER performance with appropriate doping amount of Cu. It just needs a potential of 144 mV to obtain the current density of 10 mA cm−2 in 1.0 M KOH, which is smaller than that of CuNiS@Ni 2 P/NF-0.25 (206 mV) and CuNiS@Ni 2 P/NF-0.125 (219 mV). The excellent HER performance of CuNiS@Ni 2 P/NF nanosheet arrays can be ascribed to: (i) the moderate Cu-doped effectively optimized the electronic structure and morphology of the electrocatalyst; (ii) typical nanosheet arrays structures exposing more active sites; (iii) the high immanent activity excited by the multi-component synergy. • Cu-doped bimetallic phosphosulphide nanosheet arrays on Ni foam has been prepared. • The moderate amount of Cu doping could optimize the electronic structure of the product. • The typical structure and multi-component synergy contribute to the enhanced performance. [ABSTRACT FROM AUTHOR]

Phosphorization of molybdates has been shown to promote hydrogen evolution reaction (HER) activity but is usually detrimental to oxygen evolution reaction (OER) activity, frustrating efforts to create bifunctional HER/OER electrocatalysts. Herein, we show that Fe 2 O 3 -modulated P-doped CoMoO 4 on nickel foam (Fe-P-CMO) is an excellent bifunctional HER/OER electrocatalyst in alkaline media, with the adverse effect of phosphorization on the OER activity of CoMoO 4 being countered via Fe 2 O 3 introduction. An alkaline splitting electrolyser assembled directly using the self-supporting Fe-P-CMO electrode possessed outstanding long-term durability with ultralow cell voltages of 1.48 and 1.59 V required to achieve current densities of 10 and 100 mA cm−2, respectively. Detailed experimental investigations showed that during HER, P-doped CoMoO 4 in Fe-P-CMO underwent surface reconstruction with the in-situ formation of Co(OH) 2 on the P-CoMoO 4 (Co(OH) 2 /P-CoMoO 4). During OER, P-doped CoMoO 4 was deeply reconstructed to CoOOH with the complete dissolution of Mo, leading to the in-situ formation of Fe 2 O 3 /CoOOH heterojunctions. [Display omitted] • A heterostructured Fe 2 O 3 /P-CoMoO 4 catalyst on Ni foam (Fe-P-CMO) was prepared. • Fe-P-CMO is a state-of-the-art bifunctional catalyst for overall water splitting. • Only 1.59 V is needed for Fe-P-CMO to drive 100 mA cm−2 for overall water splitting. • The reconstruction processes of Fe-P-CMO during HER and OER were revealed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) have attracted considerable attention as an advanced electrocatalyst for hydrogen evolution reaction (HER). Nevertheless, the catalytic efficiency of single-component TMPs is still restricted that cannot endure long-term running and easy to be corroded especially under harsh conditions. In this work, a multicomponent electrocatalyst combined with CoP/Ni 2 P heteronanoparticles and Co/Ni single-atom active sites (denoted as N–C@CoP/Ni 2 P) is rational designed and prepared. The obtained N–C@CoP/Ni 2 P electrode material exhibits enhanced performance with the overpotential of 153 mV at 10 mA cm−2, and the small Tafel value of 53.01 mV dec−1 in 0.5 M H 2 SO 4 , and a satisfied result is obtained in basic media as well. The outstanding HER performance is mainly benefiting from the synergistic effect between CoP and Ni 2 P, and the highly catalytic faction of atomic Co/Ni dual sites. Furthermore, a powerful conductive network fabricated by N-doped carbon skeleton and in-situ grown CNTs improves the conductivity of catalyst. Such a stereoscopic 3D nanostructure is also facile to accelerate the shuttle of electrons and ions. • A multicomponent electrocatalyst is rational designed and prepared. • The synergistic and catalytic effect brings it remarkable HER activity. • The hybrid catalyst endows with outstanding long-term durability. [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]

The non-precious transition metal phosphides (TMPs) as robust and effective hydrogen evolution reaction (HER) catalysts have attracted enormous attention, due to the merits of earth-abundance, low price, desirable stability and high efficiency. However, the conventional preparation process of this kind of catalyst is inconvenient. Herein, we report a facile approach toward the fabrication of nickel phosphide (Ni 2 P) assembled on carbon cloth (CC) via the coupling method of electroless plating and low temperature phosphorization. Then, the crystallinity, morphology and chemical component of fabricated self-supporting Ni 2 P/CC catalyst employed for the HER process were characterized, and the HER property was successively evaluated in three types of electrolytes (i.e., acidic, neutral and alkaline solutions). The as-prepared Ni 2 P/CC catalyst displays a remarkable HER performance, which can be corroborated by the small Tafel slope (b = 50 mV dec−1), high exchange current density (j 0 = 6.6 × 10−2 mA cm−2), acceptable overpotential (119 mV) to attain the current density of 10 mA cm−2, as well as the superb stability (<5% decay after 24 h potentiostatic test) in 0.5 M H 2 SO 4. In addition, it should be noted that the HER process of Ni 2 P/CC catalyst can be competent for the reduction of nitrate from the solution, and an efficiency of 63.2% for this nutrient pollutant is achieved. Image 1 • Ni–P coating deposited on CC can be sufficiently phosphorized to Ni 2 P. • Ni 2 P/CC composite can be easily fabricated via a facile approach. • Ni 2 P/CC composite exhibits an excellent HER property. • The HER process is helpful to remove nitrate from the solution. • Ni 2 P/CC sample is competent for the recommended candidate of HER catalyst. [ABSTRACT FROM AUTHOR]

Recently, metal selenides/phosphides have attracted increasing interest as electrode candidates for energy storage devices due to their high conductivity, redox activity, and specific capacity. Herein, we report the cobalt selenate-cobalt phosphide (CoSeO 3 -CoP 3) composite materials by a two-step synthesis method. Initially, the CoSeO 3 was rapidly synthesized via a facile single-step hydrothermal method for 30 min (CSO-30). Benefitting from rich redox-activity and morphological advantages, the CSO-30 electrode exhibited a higher areal capacity (C A) of 351 µAh cm−2 (specific capacity (C S) of 159.5 mAh g−1) at 2 mA cm−2 than those of the CSO electrodes obtained for 15 and 45 min. In the next step, the phosphorization process was performed to modify/alter the CSO-30 crystal structure by incorporating the phosphorus element, which leads to the formation of CoSeO 3 -CoP 3 (CSO-CP) composite. The resultant CSO-CP electrode delivered an improved C A of 627.7 µAh cm−2 (C S of 179.3 mAh g−1) at 2 mA cm−2 compared to the CSO-30 electrode. Furthermore, a hybrid supercapacitor (HSC) cell was fabricated with CSO-CP and activated carbon electrodes. The HSC revealed a maximum energy density of 0.43 mWh cm−2 and a maximum power density of 18.1 mW cm−2. Moreover, the feasibility of the HSC was verified by powering various electronic devices. • The CoSeO 3 was successfully synthesized by a single-step hydrothermal method within 30 min • The phosphorus was incorporated into the CSO-30 electrode in the presence of N 2 gas atmosphere. • The CSO-CP electrode showed an enhanced C A of 627.7 µAh cm−2 (C S of 179.3 mAh g−1). • The CSO-CP electrode illustrated the retention of 101.4 % after 12500 GCD cycles. • The fabricated hybrid supercapacitor cell showed excellent energy storage properties. [ABSTRACT FROM AUTHOR]

The development of a low cost, high performance and stable catalyst is an important prerequisite for the widespread application of efficient hydrogen production from sodium borohydride (NaBH 4). Herein, Ni-BTC is derived into CoP-NiCoP/NC catalyst consisting of CoP-NiCoP nanorods and nitrogen-doped carbon (NC) microsphere by hydrothermal and gas-phase phosphorylation methods. The CoP-NiCoP/NC catalyst exhibits good catalytic activity, with a high hydrogen evolution rate of NaBH 4 reaching 7052 mL·min−1·g−1 at 303 K, and an activation energy of only 35.57 kJ·mol−1. This is significantly better than most catalysts reported previously. In addition, the CoP-NiCoP/NC catalyst demonstrates good durability with 75 % of the original catalytic activity after 10 performance testing. This excellent catalytic performance is achieved thanks to its porous microsphere structural design and the cooperative effect between CoP and NiCoP. This catalyst with high catalytic performance and mild preparation conditions is promising for future actual applications. • Novel CoP-NiCoP/NC catalyst was prepared by three-step simple methods. • The CoP-NiCoP/NC catalyst composed of CoP-NiCoP nanorods and nitrogen-doped carbon (NC) microspheres. • The synergistic catalysis of CoP and NiCoP effectively improved the catalytic activity. • The catalyst achieved excellent hydrogen production performance and lower Ea of 35.57 kJ·mol−1. [ABSTRACT FROM AUTHOR]

Abstract Developing cheaper but efficient electrocatalysts toward hydrogen evolution reaction (HER) are highly desirable for the sustainable energy conversion techniques. The nanostructured CoP has been proved to be one of the most efficient non-noble metal HER catalyst. However, to further improve their performance in hydrogen evolution reaction (HER) is still a challenging task. In the present work, we prepare the nanohybrid CeO 2 -CoP-C catalyst with high porosity through a co-ionic-exchange with Co and Ce ions using the metal-organic frameworks (MOFs) as template followed with a low-temperature phosphorization route. The high porosity of the catalysts is conductive to the diffusion and mass transfer of the reactants on the catalyst surface. Meanwhile, the doping of rare earth (RE) element modulates the electronic structure of the CoP nanoparticles, and the carbon skeleton left over from the annealed MOF is beneficial to the electronic conduction in the catalyst. Electrochemical tests showed that the ternary CeO 2 -CoP-C/CC hybrid nanostructure presented overpotential of 71 mV at 10 mV cm−2 (η 10), which is much higher than that of the binary CoP-C/CC catalysts (i.e., 132 mV). In addition, the ternary catalyst also presented a superior long-term durability in an acidic electrolyte. This work opens up a potential strategy for designing more efficient CoP-based catalysts toward electrochemical water splitting. Graphical abstract The porous ternary CeO 2 -CoP-carbon skeleton hybrid nanoparticles were synthesized with MOF (ZIF-8) as a template via a modified co-ionic exchange and phosphorization method, and they show an obvious enhancement in their HER performance. Image 1 Highlights • A porous ternary CeO 2 -CoP-C hybrid nanostructure was constructed. • The carbon skeleton provided a superior mass diffusion and connectivity. • The CeO 2 -dopping greatly promotes the HER performance of CoP. [ABSTRACT FROM AUTHOR]

The phosphorized radial microspheres of Ni-Co-O on a porous Ti plate (Ni-Co-O/Ti) were fabricated for the electrocatalysis of hydrogen evolution reaction (HER). They are characterized by SEM, TEM, XRD, XPS and BET. The Ni-Co-P/Ti exhibited the low onset potential of −100 mV, achieving the current densities of 10 and 50 mA/cm 2 at the overpotentials of 20 and 80 mV, respectively. The Tafel slope is approximately 43 mV/dec, which is close to that of commercial Pt catalyst and lower than many previous reports. On the other hand, the Ni-Co-O/Ti exhibited high electrocatalytic oxidation of glucose with a relatively low onset potential at 0.29 V, where glucose was introduced to decrease the cell potential of water splitting. [ABSTRACT FROM AUTHOR]

Hitherto, WP has been used as hydrogen evolution reaction (HER) catalyst. However, its activity and complexity of nanostructure synthesis greatly limit applications in hydrogen production. Therefore, in this work, the coral-like WP nanorod arrays propagated on W foils (C-WP/W) are synthesized through an in situ oxidation and phosphorization route. The obtained 3D C-WP/W catalysis system can directly work as hydrogen evolution reaction (HER) electrode, and exhibits excellent activity and stability in either acid or alkaline media. It only requires a small overpotential of 109 and 133 mV at 10 mA/cm 2 , and 189 and 206 mV at 100 mA/cm 2 in 0.5 M H 2 SO 4 and 1.0 M KOH, respectively, which is the best HER catalyst ever reported among pure tungsten phosphide materials. This study paves the way for integrations of 3D HER electrodes with low-cost, high performance and for efficient applications under complicated conditions. [ABSTRACT FROM AUTHOR]

The metal-organic frameworks (MOFs)/derivates emerged as promising catalysts for hydrogen generation from electrolyzing water, however, further improvements in the activities are still awaited. Herein, bimetallic MOFs and the derivates were developed for catalyzing the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) by regulating the morphology, and activity of the intermediates. We demonstrated the activity and morphology of the catalysts strongly correlated with the atomic ratio of Ni and Co in bimetallic MOFs. The hierarchical Ni 0.1 Co 0.9 -MOF delivered a relatively low overpotential of 384 mV to afford 100 mA/cm2 for OER, but a high overpotential of 512 mV for HER. While the phosphide Ni 0.1 Co 0.9 P only needed an overpotential of 276 mV to deliver 100 mA/cm2 for HER. And we discussed the roles of bimetallic sites and phosphorous in OER and HER in depth. More importantly the Ni 0.1 Co 0.9 -MOF and Ni 0.1 Co 0.9 P were integrated to drive the overall water splitting, at a current density of 10 mA/cm2, the overpotential value is 500 mV. This work provided insights into the exploration of efficient MOFs/derivates catalysts and shed new light on the novel combination for water electrolysis. [Display omitted] • The hierarchical nanoflower morphology is elaborately fabricated. • The OER activity highly depends on the metallic atomic ratio in NiCo-MOF. • Ni 0.1 Co 0.9 -MOF performs the most superior OER performance. • Boosted HER performance is achieved by phosphorization (Ni 0.1 Co 0.9 P). • Paring Ni 0.1 Co 0.9 -MOF and Ni 0.1 Co 0.9 P generate excellent water electrolysis. [ABSTRACT FROM AUTHOR]

• Triphenylphosphine (PPh3) was used for the phosphorization of g-C 3 N 4. • g-C 3 N 4 (PPh3) showed extended light absorption and promoted charge separation. • g-C 3 N 4 (PPh3) exhibited higher photocatalytic activity than g-C 3 N 4. It is an effective strategy to regulate the structure of photocatalysts for enhanced photocatalytic hydrogen evolution. In this work, a facile method was developed to introduce P atoms into g-C 3 N 4 via the thermal calcination treatment. In contrast to pristine g-C 3 N 4 , the obtained P-CN(PPh3) exhibited a negative shift of conduction band edge with enhanced light absorption after the introduction of P atoms into g-C 3 N 4 , thus benefiting the photocatalytic hydrogen evolution. Moreover, the introduction of P element in g-C 3 N 4 can also improve the charge separation during the photocatalytic hydrogen reaction, significantly accelerating the photocatalytic hydrogen production rate of P-CN(PPh3). [ABSTRACT FROM AUTHOR]

• The Co-Mo-Ni phosphide was used as bifunctional electrocatalysts with hierarchical heterostructured nanoarrays. • CMNP-X (X = 4,5,6 and 7) reveals low overpotential and outstanding overall water splitting performance with high stability. • The synergistic effect of phosphorylation and heterostructure could significantly modulate the electronic structures. At present, it is still a critical challenge to simultaneously facilitate the overall water splitting reaction by an electrocatalyst with high activity, good durability, and low cost. Herein, ultrathin nanosheets Co-Mo-Ni heterostructured phosphide bifunctional electrocatalysts were constructed on Cu(OH) 2 nanorod arrays toward an efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The electrocatalysts are rationally designed to be composed of heterostructure CoMoP, MoNiP, and Cu 3 P. The formation of M−P bonds can capture intermediates, avoid deactivation, and induce ligand effects to enhance catalytic performance. Therefore, the synergistic effect of heterogeneous structure and phosphorylation is the main contribution to promoting HER and OER. As a result, the bifunctional electrocatalysts exhibit highly efficient with HER overpotentials of 106 mV and 160 mV at current densities of 100 and 200 mA cm−2, and OER overpotentials of 243 mV and 280 mV, respectively. The constructed overall water-splitting cell realized a low potential of 1.65 V with a current density of 100 mA cm−2 and long-term stability, which is comparable to the reported bifunctional catalysts. [ABSTRACT FROM AUTHOR]

• Stainless steel mess with a three-dimensional network structure substrate to grow NiCoP-CoP electroactive catalyst. • NiCoP@SSM electrocatalyst reveals an excellent performance and stability towards hydrogen evolution reaction. • Synergetic effect between Pδ− with a high affinity towards proton-acceptor, and Coδ+/ Niδ+ as hydride-acceptor. The stainless steel mesh (SSM) has received remarkable attention for hydrogen and oxygen evolution reactions. It was demonstrated that the SSM exhibits admirable performance towards oxygen evolution reaction (OER) electrocatalysis, while its catalytic activity for hydrogen evolution reaction (HER) remains quite low. This obstructs the utilization of SSM-based catalysts for sustainable complete water electrolysis. In this study, a facile hydrothermal route followed by a phosphorization process was adopted to transform commercially available SSM materials into high-performance and stable electrocatalysts for alkaline HER. We report an interconnected NiCoP-CoP sponge-like structure on SSM substrate without polymer binder. Benefiting from the 3D construction with high exposed surface area, close contact between electroactive species and conductive surface, and facilitated infiltration of electrolyte, the as-prepared NiCoP@SSM electrocatalyst brought an improved catalytic activity for HER, required a low overpotential of 138 mV to derive a current density of 10 mAcm−2 in 1.0 M KOH aqueous solution. The high performance of the NiCoP@SSM catalyst has also unveiled fast reaction kinetics (presents a small Tafel slope of 74 mV/dec), a relatively large electrochemical active surface area (ECSA), and small charge transfer resistance. Furthermore, the NiCoP@SSM electrode also presented excellent stability during long-term measurements, making it one of the most encouraging HER electrodes to date. This research study paves the way for the development of HER-active electrocatalysts made from SSMs that are commercially available, low-cost, and highly active. [Display omitted] [ABSTRACT FROM AUTHOR]

Transition-metal oxides as the pseudocapacitive material have been increasingly investigated due to their high theoretical specific capacitance for supercapacitors (SCs). However, restricted to lack of active sites and poor conductivity, they usually display limited experimental capacitance, barely satisfying high energy density of SCs. Herein, we describe phosphorus functionalized low-crystallinity Co 3 O 4 and Fe 2 O 3 nanorod arrays on carbon cloth (Co 3 O 4 -P and Fe 2 O 3 -P), which can respectively behave as the flexible 3D cathode and anode for SCs. The formed phosphide on the surface of metal oxide provides the enhancement of electron transfer and the reduction of ions diffusion pathway. The optimized Co 3 O 4 -P 1.0 h cathode and Fe 2 O 3 -P 1.0 h anode deliver a high capacitance of 1180 and 477 mF cm−2, respectively. The asymmetric supercapacitor Co 3 O 4 -P//Fe 2 O 3 -P has been verified with an operating voltage of 1.5 V and stability over 5000 cycles and delivers an energy density of 73.6 μWh cm−2 at a power density of 0.38 mW cm−2. The phosphorus activation is expected to be widely applicable for the fabrication of porous and low-crystalline transition-metal oxide, thus opening up new avenues for energy storage. [Display omitted] • Low-crystalline Co 3 O 4 -P and Fe 2 O 3 -P nanoarrays were fabricated by incomplete phosphorization treatment. • Structure defect of metal oxides by rational phosphorization favors electrolyte ions transport. • The formation of phosphide in bulk phase accelerates electrons transfer of electrode. • Co 3 O 4 -P//Fe 2 O 3 -P assembled ASC delivered high energy density and superior cycling stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • The CoMoP-rGO/CNT was synthesized by hydrothermal and phosphating. • The three-dimensional rGO/CNTs can improve the conductivity of substrate materials. • The vertical open structure of CoMoP nanosheet arrays facilitates mass transfer. • The CoMoP-rGO/CNT exhibits HER activity and durability in pH-universal. Although great progress has been made in the area of electrocatalysis, the design of earth-rich and efficient electrocatalysts remains a major challenge. It is of great significance to explore non-noble metal-based electrocatalysts with efficient and stable performance for hydrogen evolution reaction (HER) in the relatively wide pH range. Herein, a self-supporting three-dimensional (3D) CoMoP-rGO/CNT catalyst was synthesized to achieve high efficiency of HER in acidic and basic solution. The combination of CNTs and rGO improves the conductivity of the substrate material, while the self-supporting structure avoids the use of the binder to expose the active sites, and the open structure of the vertically arranged CoMoP nanosheet arrays is benefit for the interaction between the electrolyte and the active sites. Thus, the CoMoP-rGO/CNT showed excellent activity and durability for HER with a low overpotential of 66 mV and 86 mV at a current density of −10 mA·cm−2 in acidic (0.5 M H 2 SO 4) and basic (1 M KOH) solution, respectively. The three-dimensional structure of CoMoP-rGO/CNT can enhance electron migration and mass transfer, while Co and Mo also play an important role in regulating surface active sites. This work may open a new way for the design of earth-rich and low-cost nanomaterials for electrocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • The electrocatalytic activity of Ni and Co films for HER is enhanced by electro-phosphorization. • The electro-phosphorization are realized in hypophosphite solution under electric current action. • Ni film has an overpotential of 57 mV at 10 mA·cm−2 after phosphorization. The electrodeposited nickel and cobalt films are directly phosphorized in alkaline hypophosphite solution under the action of electric current. After the electro-phosphorization process, the morphology of nickel and cobalt films change obviously, and phosphorus element can be detected in the phosphorized films according to the EDS and XPS tests. The electrocatalytic performance of nickel and cobalt films for hydrogen evolution reaction are obviously enhanced by the electro-phosphorization treatment. Especially, the phosphorized nickel film has an overpotential of 57 mV at the current density of 10 mA·cm−2. [ABSTRACT FROM AUTHOR]

The main energy consumption of industrial water electrolysis is electric energy, which accounts for ca. 80% of the total cost of water electrolysis. Developing highly efficient bifunctional electrocatalyst for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential to reduce the energy consumption. Herein, nickel foam (NF)-supported NiCoP nanorod array catalyst is prepared and used for HER and OER. Not only at a small current density (10 mA/cm2), but also at the commercially required high current density (≥500 mA/cm2), NiCoP/NF catalyst shows excellent bifunctional properties with extremely low overpotential and high stability. Small overpotentials of 60 and 253 mV are needed to drive the current density of 10 mA/cm2 for HER and OER, respectively, and the cell voltage of overall water splitting is only 1.55 V. At the high current density of 500 mA/cm2, the overpotentials are 180 and 365 mV, and the corresponding cell voltage is only 1.83 V. Furthermore, the cell voltage hardly changes within 24 h of overall water splitting test, which makes the catalyst have promising applications in the industrial water electrolysis. The high performance of NiCoP/NF outperforms the commercial RuO 2 -Pt/C couple and most of the bifunctional Ni/Co-based catalysts reported so far. Image 1 • Ni foam-supported NiCoP nanorod array catalyst is prepared and used for HER and OER. • Not only at low but also at high current densities, NiCoP/NF shows high activity. • NiCoP/NF requires only 1.83 V to drive 500 mA/cm2 for overall water splitting. • Hydroxides in-situ formed in the catalytic process contribute to the high activity. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) is a vital process in numerous energy conversion systems, and therefore, considerable attention has been devoted to the fabrication of nonnoble and highly efficient electrode materials for OER. Herein, Co nanoparticles embedded in the N, P-codoped porous carbon (Co/P-N-C) are synthesized using a novel Co-based metal-organic polymer (Co-MOP) as the precursor through carbonization and a subsequent phosphorization treatment process. When the phosphorization treatment is carried out at pH 3, Co/P-N-C exhibits a very low overpotential of 300 mV for a current density of 10 mA cm−2 with a small Tafel slope of 61 mV dec−1 and excellent stability over 20000 s. The electrocatalytic performance of Co/P-N-C was even better than that of the commercial RuO 2 material. Density functional theory calculations were used to simulate the electrocatalytic process and to verify the experimental findings, which showed that the superior OER performance was attributed to the active sites of doped P and Co nanoparticles. This viable strategy of using a novel Co-MOP to create a novel phosphorized Co/P-N-C microporous carbon-based material may expand the opportunities for the exploration of high-performance and robust nonnoble metal electrocatalysts for energy-conversion reactions. Co atoms on N, P co-doped porous carbon via phosphorization on Co-MOP exhibit excellent OER performance due to the synergistic effects of P and Co. Image 1 • A phosphorization strategy to prepare a porous MOP-derived Co-P-N-C nanosphere. • The as-obtained yolk-shell Co-P-N-C nanosphere possesses the high electrocatalytic activity for OER. • Reveal the P and Co synergistic mechanism for forming more active sites of Co-P-N-C. [ABSTRACT FROM AUTHOR]

• Develop new CoP nanocrystals by phosphating the Co 3 O 4 nanocubes precursor. • New type of non-metallic HER catalyst with initial potential of only 87 mV. • Self-assembled CoP nanocrystals with good catalytic performance. • Provide new way for preparing efficient and inexpensive HER electrocatalysts. Electrocatalytic water splitting reactions include hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). It provides an effective method for producing high-purity hydrogen as a sustainable energy source. In order to solve the growing energy shortage and environmental damage, the development and synthesis of efficient and inexpensive hydrogen evolution reaction (HER) electrocatalysts is urgently needed. Traditional reaction catalysts such as Pt/Rh/Ir and their oxides (such as IrO 2 , RuO 2) have limited their wide application as electrocatalysts due to their high prices and small reserves. In this work, CoP nanocrystals by phosphating the Co 3 O 4 nanocubes precursor were successfully synthesized. CoP nanocrystals are a new type of non-metallic HER catalyst that can work under alkaline conditions. Its initial potential is only 87 mV at a current density of 10 mA cm−2, and the Tafel slope is 105 mV dec−1. The catalyst can maintain the catalytic performance for 12 h in 1 M KOH solution, and the performance can still be maintained above 95.44%. [ABSTRACT FROM AUTHOR]

• Develop new self-assembled Ni/Co phosphides composite spheres. • Carbon nanospheres via a hydrothermal process and effective manner. • Exhibit excellent HER electrocatalytic activity. • Significant potentials in composite electrocatalyst design. Because of their high catalytic activity and abundant resources, nonprecious transition metal phosphides are favorable substitutes for noble metals as hydrogen evolution reaction (HER) electrocatalysts. In this work, self-assembled Ni/Co phosphide composite N-doped carbon spheres were successfully prepared via a hydrothermal process, which had abundant exposed active sites for the HER. The as-obtained samples exhibited excellent electrocatalytic activity for the HER with an overpotential of only 160 mV (vs. RHE) at a current density of 10 mA cm−2 in a 0.5 M H 2 SO 4 solution and a comparatively low Tafel slope (57 mV dec−1). Additionally, the Ni 2 P/CoP spheres also show good stability after 120 h and 5000 cycles of a cyclic voltammetry test. Their highly efficient catalytic activity for the HER is attributed to the specific spherical structure, which provides exposed Ni 2 P and CoP for favorable adsorption and desorption of hydrogen. Therefore, nonprecious transition metal phosphide spheres may provide a promising strategy to improve the catalytic activity of HER electrocatalysts. [ABSTRACT FROM AUTHOR]

Constructing well-defined nanointerfaces is vital to enhance the catalytic performances through electronic coupling effects from different components. However, it is still a challenge to construct metal selenides-based interfacial nanomaterials with satisfactory oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performances for overall water splitting. Herein, sandwich-like structured NiSe 2 /Ni 2 P@FeP nanosheet arrays are rationally constructed, which starts from NiSe 2 arrays directly on carbon cloth as backbones, followed by coating FeP nanoparticles on the backbones through the phosphorization process. Further, abundant nanointerfaces with rich defects and disordered structure are constructed during the phosphorization process, which can boost the charge transfer rate and provide rich electroactive sites. Consequently, as-synthesized NiSe 2 /Ni 2 P@FeP nanosheet arrays exhibit good HER and OER performances with small overpotentials, low Tafel slopes and good stability. Further, the overall water splitting device built by NiSe 2 /Ni 2 P@FeP exhibits a voltage of 1.554 V to attain 10 mA cm−2. Our current work may provide some new insights on rationally constructing nanointerfaces with rich defects to boost the catalytic performances for overall water splitting. Image 1 • A two-step strategy is developed to construct NiSe 2 /Ni 2 P@FeP electrocatalysts. • The abundant interfaces can boost transfer rate and provide rich active sites. • NiSe 2 /Ni 2 P@FeP exhibits superior activities and stability in HER and OER tests. • A low voltage of 1.554 V is achieved at 10 mA cm−2 for the constructed full-cell. [ABSTRACT FROM AUTHOR]

Highlights from the article: Hydrogen Evolution: Embedding RhPx in N, P Co-Doped Carbon Nanoshells Through Synergetic Phosphorization and Pyrolysis for Efficient Hydrogen Evolution (Adv. Funct. Keywords: carbon nanoshells; hydrogen evolution reaction; phosphorization; pyrolysis; RhPx Pyrolysis, hydrogen evolution reaction, phosphorization, carbon nanoshells, RhPx.

Owning to the energy crisis and environmental pollution, it is urgent to develop an efficient and earth‐abundant electrocatalyst for water splitting. In this work, the Cu2O cubes are first synthesized through a modified precipitation method, and it is subsequently selected as the Cu2+ source to synthesize 3D MOF (metal‐organic framework, Cu‐BDC) nanoarray by a facile and efficient bottom‐up method. Next, porous Cu3P@C is prepared via the low‐temperature phosphorization of 3D Cu‐BDC nanoarray as a high‐performance electrocatalyst for oxygen and hydrogen evolution reactions (OER and HER). In particular, the effect of reaction temperature on the morphology of 3D Cu‐BDC precursor is studied in detail. Experimental results reveal that Cu3P@C‐120 derived from sea urchin‐like Cu‐BDC exhibits excellent electrocatalytic performance owning to the high special surface area, developed porous structure, and the uniform dispersion of Cu3P nanoparticles, which affords the current density of 10 mA cm−2 at low overpotentials of 300 and 124 mV for OER (alkaline medium) and HER (acidic medium) with Tafel slopes of 24 and 29 mV dec−1, respectively. Remarkably, Cu3P@C‐120 also exhibits an excellent durability for OER and HER, making it an efficient bifunctional electrocatalyst for application in the production of clean hydrogen fuel. [ABSTRACT FROM AUTHOR]