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Transition metal phosphides (TMPs) have emerged as an alternative to precious metals as efficient and low‐cost catalysts for water electrolysis. Elemental doping and morphology control are effective approaches to further improve the performance of TMPs. Herein, Fe‐doped CoP nanoframes (Fe‐CoP NFs) with specific open cage configuration were designed and synthesized. The unique nano‐framework structured Fe‐CoP material shows overpotentials of only 255 and 122 mV at 10 mA cm−2 for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively, overwhelming most transition metal phosphides. For overall water splitting, the cell voltage is 1.65 V for Fe‐CoP NFs at a current density of 10 mA cm−2, much superior to what is observed for the classical nanocubic structures. Fe‐CoP NFs show no activity degradation up to 100 h which contrasts sharply with the rapidly decaying performance of noble metal catalyst reference. The superior electrocatalytic performance of Fe‐CoP NFs due to abundant accessible active sites, reduced kinetic energy barrier, and preferable *O‐containing intermediate adsorption is demonstrated through experimental observations and theoretical calculations. Our findings could provide a potential method for the preparation of multifunctional material with hollow structures and offer more hopeful prospects for obtaining efficient earth‐abundant catalysts for water splitting. [ABSTRACT FROM AUTHOR]

Electrochemical conversion from nitrate to ammonia is a key step in sustainable ammonia production. However, it suffers from low productive efficiency or high energy consumption due to a lack of desired electrocatalysts. Here we report nickel cobalt phosphide (NiCoP) catalysts for nitrate‐to‐ammonia electrocatalysis that display a record‐high catalytic current density of −702±7 mA cm−2, ammonia production rate of 5415±26 mmol gcat−1 h−1 and Faraday efficiency of 99.7±0.2 % at −0.3 V vs. RHE, affording the estimated energy consumption as low as 22.7 kWh kgammonia−1. Theoretical and experimental results reveal that these catalysts benefit from hydrogen poisoning effects, which leave behind catalytically inert adsorbed hydrogen species (HI*) at Co‐hollow sites and thereupon enable ideally reactive HII* at secondary Co−P sites. The dimerization between HI* and HII* for H2 evolution is blocked due to the catalytic inertia of HI* thereby the HII* drives nitrate hydrogenation timely. With these catalysts, the continuous ammonia production is further shown in an electrolyser with a real energy consumption of 18.9 kWh kgammonia−1. [ABSTRACT FROM AUTHOR]

Highly efficient novel electrocatalysts for hydrogen/oxygen production are urgently required, for noble metal‐based catalysts substitution. Cobalt phosphides have shown great potential for serving as bifunctional catalysts, owing to the cost effectiveness and high conductivity. However, the water splitting ability of them is still not comparative with commercial noble counterparts. In this work, we reported a Br‐induced strategy, to obtain an ultra‐hydrophilic isostructural Br0.036─Co1.085P@NF catalyst by a gas‐solid reaction method. As a typical halogen element, the introduction of Br can greatly enhance the surficial hydrophilicity and thus further impart ideal adsorption ability for water molecules. Meanwhile, the electronic structure could be regulated to further induce the generation of isostructural cobalt phosphides (CoP/Co2P). As a result, the contact angle of Br0.036─Co1.085P@NF catalysts nearly cannot be caught owing to the ultra‐hydrophilicity. It is also confirmed that, the d‐band center of Co shows apparent negative shift after Br introduction, which reduces the adsorption energy of oxygen‐containing intermediates thereby facilitating the desorption process. Besides, the introduction of Br can also reduce the barrier of O2 formation, show more favorable dynamic behaviors. This work proved the accessibility for an effective design strategy on halogen‐induced isostructural transition metal phosphides catalysts for high‐performance overall water splitting. [ABSTRACT FROM AUTHOR]

The development of bifunctional, non‐noble metal‐based electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) through morphology and electronic engineering is highly attractive for efficient water splitting. Herein, hierarchical nanoarrays consisting of crystalline cobalt phosphide nanorods covered by amorphous Fe‐doped cobalt phosphide nanocuboids (CoP/FeCoPx) are constructed as bifunctional catalysts for both HER and OER. Experimental results and theoretical calculations reveal that the catalysts exhibit balanced dual‐catalytic properties due to simultaneous introduction of Fe doping and phosphorus vacancies, leading to an optimized electronic structure of the CoP/FeCoPx. Furthermore, the hierarchical nanoarrays made of crystalline/amorphous heterostructures significantly enhance the performance of the electrocatalysts. As a result, the CoP/FeCoPx catalyst demonstrates remarkable performance in both HER and OER, with overpotentials of 74 and 237 mV at 10 mA cm−2 in 1 m KOH, respectively, as well as a low cell voltage of 1.53 V at 10 mA cm−2 for alkaline overall water splitting. This work integrates the morphology engineering involving design of hierarchical crystalline/amorphous nanoarrays and the electronic engineering through Fe doping and phosphorus vacancies for efficient water electrolysis. It may open a new route toward rational design and feasible fabrication of high‐performance, multifunctional, non‐noble metal‐based electrocatalysts for energy conversion. [ABSTRACT FROM AUTHOR]

It is of great significance to design photoelectrodes with high carrier separation and transport efficiency in photocatalytic water separation systems. In this study, we used a simple electrochemical deposition method to regulate the load of co‐catalyst CoP on TiO2 nanorods to improve the photoelectrochemical properties. The photocurrent density of TiO2/CoP (20) photoanode at 1.23 V increases to 1.57 mA/cm2, which is 3.4 times that of original TiO2. Long‐term photoelectrolysis reveals that this electrode has excellent stability. Mechanistic studies support the role of CoP nanoparticles in improving photoelectrochemical property and imply that the excellent photoelectrochemical property of TiO2/CoP photoanode is mainly ascribed to the suppress of surface photogenerated electrons and holes recombination due to the construction of built‐in electric field between TiO2 and CoP. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) over perovskite oxides, upon undergoing a lattice oxygen oxidation mechanism, is strongly oxygen vacancy‐correlated as determined by the oxygen ion diffusivity. Despite substantial efforts having been devoted to tuning the oxygen vacancy concentration in perovskite oxides, the impact of the concomitant altering of oxygen vacancy ordering is often underestimated. In particular, the underlying mechanism of how the ordering and the concentration of oxygen vacancy affect the lattice OER, and how to well balance them still remain inadequately understood. Herein, a series of Sr1−xCaxCo0.5Fe0.5O3−δ with gradually increased oxygen vacancy concentration and ordering are synthesized. Theoretical calculations indicated that a higher oxygen vacancy concentration promoted the lattice oxygen migration, whereas a higher oxygen vacancy ordering impeded it. Particularly, Sr0.5Ca0.5Co0.5Fe0.5O3−δ with a relatively higher oxygen vacancy concentration and a lower ordering displayed the maximum oxygen diffusion rate and the optimal OER activity, affording a current density of 10 mA cm−2 at a quite low overpotential of 310.2 mV, together with a small Tafel slope of 55.87 mV dec−1. This study sheds light on the critical influence of oxygen vacancy configuration on the lattice OER, and paves a compromised avenue to screen and design advanced electrocatalysts for various electrochemical devices. [ABSTRACT FROM AUTHOR]

A stable and highly active core‐shell heterostructure electrocatalyst is essential for catalyzing oxygen evolution reaction (OER). Here, a dual‐trimetallic core‐shell heterostructure OER electrocatalyst that consists of a NiFeWS2 inner core and an amorphous NiFeW(OH)z outer shell is designed and synthesized using in situ electrochemical tuning. The electrochemical measurements of different as‐synthesized catalysts with a similar mass loading suggest that the core‐shell Ni0.66Fe0.17W0.17S2@amorphous NiFeW(OH)z nanosheets exhibit the highest overall performance compared with that of other bimetallic reference catalysts for the OER. Additionally, the nanosheet arrays were in situ grown on hydrophilic‐treated carbon paper to fabricate an integrated three‐dimensional electrode that affords a current density of 10 mA cm−2 at a small overpotential of 182 mV and a low Tafel slope of 35 mV decade−1 in basic media. The Faradaic efficiency of core‐shell Ni0.66Fe0.17W0.17S2@amorphous NiFeW(OH)z is as high as 99.5% for OER. The scanning electron microscope, transmission electron microscope, and X‐ray photoelectron spectroscopy analyses confirm that this electrode has excellent stability in morphology and elementary composition after long‐term electrochemical measurements. Importantly, density functional theory calculations further indicate that the core‐shell heterojunction increased the conductivity of the catalyst, optimized the adsorption energy of the OER intermediates, and improved the OER activity. This study provides a universal strategy for designing more active core‐shell structure electrocatalysts based on the rule of coordinated regulation between electronic transport and active sites. [ABSTRACT FROM AUTHOR]

This study presents the synthesis and electrocatalytic performance of the cobalt(III) complex [Co3(μ1,1,1‐O)(μ1,3‐CH3CO2)(L)3]2(DMF)3 (Cotri), featuring a double deprotonated (N,O)‐donor ligand (L2‐), where the protonated form of it (H2L) is 2,2′‐(hydrazine‐1,2‐diylidenebis(ethan‐1‐yl‐1‐ylidene))diphenol. The X‐ray structure reveals a trinuclear cobalt cluster formed with three cobalt(III) centers interlinking through oxido (μ1,1,1‐O) and acetato (μ1,3‐O2CCH3) bridges in coupling with bis‐congregator‐type chelating ligands. Cotri adopts cobalt centers of octahedral and trigonal bipyramidal coordination geometries and bears a dominant Co(2)...H(DMF) agostic interactions appraised by lattice dimethyl formamide (DMF) molecules. Further, Cotri shows promising heterogeneous electrocatalytic hydrogen evolution activity in 1 M KOH, with an overpotential of 441 mV to achieve 10 mA/cm2 current density. Tafel slope analysis suggests the Volmer–Heyrovsky step as the rate‐determining step. The number of active sites and TOF for Cotri were estimated at 4.010 × 10−8 mol and 0.2467 s−1, respectively, ensuring its excellent hydrogen generation activity. Stability assessments through controlled potential electrolysis (CPE) and cyclic voltammetry (CV) for multiple cycles addressed the transformation of Cotri to Co2O3 nanoparticles, which turned out to be a more active Co2O3 electrocatalyst. The morphology and particle size of the in situ developed Co2O3 active catalyst under the electrochemical conditions attributes to the superior hydrogen evolution activity. [ABSTRACT FROM AUTHOR]

Ammonia borane (AB) has emerged as a promising chemical hydrogen storage material. The development of efficient, stable, and cost‐effective catalysts for AB hydrolysis is the key to achieving hydrogen energy economy. Here, cobalt phosphide (CoP) is used to anchor single‐atom Pt species, acting as robust catalysts for hydrogen generation from AB hydrolysis. Thanks to the high Pt utilization and the synergy between CoP and Pt species, the optimized Pt/CoP‐100 catalyst exhibits an unprecedented hydrogen generation rate, giving a record turnover frequency (TOF) value of 39911 molH2molPt−1min−1${\mathrm{mo}}{{{\mathrm{l}}}_{{{{\mathrm{H}}}_{\mathrm{2}}}}}{\mathrm{\ mo}}{{{\mathrm{l}}}_{{\mathrm{Pt}}}}^{{\mathrm{ - 1}}}{\mathrm{\ mi}}{{{\mathrm{n}}}^{{\mathrm{ - 1}}}}$ and turnover number of 2926829 molH2molPt−1${\mathrm{mo}}{{{\mathrm{l}}}_{{{{\mathrm{H}}}_{\mathrm{2}}}}}{\mathrm{\ mo}}{{{\mathrm{l}}}_{{\mathrm{Pt}}}}^{{\mathrm{ - 1}}}$ at room temperature. These metrics surpass those of all existing state‐of‐the‐art supported metal catalysts by an order of magnitude. Density functional theory calculations reveal that the integration of single‐atom Pt onto the CoP substrate significantly enhances adsorption and dissociation processes for both water and AB molecules, thereby facilitating hydrogen production from AB hydrolysis. Interestingly, the TOF value is further elevated to 54878 molH2molPt−1min−1${\mathrm{mo}}{{{\mathrm{l}}}_{{{{\mathrm{H}}}_{\mathrm{2}}}}}{\mathrm{\ mo}}{{{\mathrm{l}}}_{{\mathrm{Pt}}}}^{{\mathrm{ - 1}}}{\mathrm{\ mi}}{{{\mathrm{n}}}^{{\mathrm{ - 1}}}}$ under UV–vis light irradiation, which can be attributed to the efficient separation and mobility of photogenerated carriers at the Pt‐CoP interface. The findings underscore the effectiveness of CoP as a support for single‐atom metals in hydrogen production, offering insights for designing high‐performance catalysts for chemical hydrogen storage. [ABSTRACT FROM AUTHOR]

Cobalt phosphides have been investigated as potentially useful electrocatalysts for accelerating hydrogen evolution. Cobalt phosphide electrocatalysts are synthesized in a single step at varied phosphating temperatures (350, 400, 450 °C) via the gas phase approach. Synthesized at a phosphating temperature of 350 °C, Co2P (CP‐350) transforms into a mixed phase that contains both Co2P and CoP (CP‐400 and CP‐450) as the phosphating temperature goes up which is confirmed by XRD. CP‐350, CP‐400, and CP‐450 exhibited overpotentials of 181, 270, and 293 mV respectively with Tafel slopes of 112, 146, and 175 mV/dec. In contrast to CP‐400 and CP‐450, CP‐350 revealed superior hydrogen evolution reaction (HER) performance and stability for up to 12 h due to its pure phase (Co2P), high surface area (151 m2/g), and high electrochemical surface area (7.02 cm2) with low charge transfer resistance. According to our work, changing the phase and active surface area of transition metal phosphide catalysts can greatly increase their HER catalytic efficiency. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting offers a most promising pathway for "green hydrogen" generation. Even so, it remains a struggle to improve the electrocatalytic performance of non‐noble metal catalysts, especially bifunctional electrocatalysts. Herein, aiming to accelerate the hydrogen and oxygen evolution reactions, an oxygen‐bridged cobalt–chromium (Co‐O‐Cr) dual‐sites catalyst anchored on cobalt phosphide synthesized through MOF‐mediation are proposed. By utilizing the filling characteristics of 3d orbitals and modulated local electronic structure of the catalytic active site, the well‐designed catalyst requires only an external voltage of 1.53 V to deliver the current density of 20 mA cm−2 during the process of water splitting apart from the superb HER and OER activity with a low overpotential of 87 and 203 mV at a current density of 10 mA cm−2, respectively. Moreover, density functional theory (DFT) calculations are utilized to unravel mechanistic investigations, including the accelerated adsorption and dissociation process of H2O on the Co‐O‐Cr moiety surface, the down‐shifted d‐band center, a lowered energy barrier for the OER and so on. This work offers a design direction for optimizing catalytic activity toward energy conversion. [ABSTRACT FROM AUTHOR]

The commonly used "catalyst on carbon" architecture as a sulfur host is difficult to jointly achieve high gravimetric and volumetric energy densities for lithium–sulfur (Li–S) batteries due to the contradiction between low tap density/poor catalytic activity of carbon and the easy agglomeration of metal‐based compounds without carbon. Here, a non‐carbon‐dominated catalytic architecture using macroporous nickel/cobalt phosphide (NiCoP) is reported as the sulfur host for Li–S batteries. The macroporous framework, which accommodates a large amount of sulfur, can accelerate the electrochemical reaction kinetics by accelerated e− transport, Li+ diffusion, and superior adsorption and catalytic activity of inherent Ni2P/CoP heterostructures. The high tap density (0.45 g cm−3) and mechanically hard features contribute to the excellent structural and physicochemical stability of the NiCoP@S electrode after the pressing and rolling process. These features enable the Li–S coin cell to exhibit excellent electrochemical performance under conditions of high sulfur loading (10.2 mg cm−2) and lean electrolyte (electrolyte/sulfur of 2 µL mg−1). Inspiringly, the assembled pouch cell can simultaneously deliver a gravimetric energy density of 345.2 Wh kg−1 and an impressive volumetric energy density of 952.7 Wh L−1 based on the entire device configuration. [ABSTRACT FROM AUTHOR]

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

Metal–organic frameworks (MOFs) derived nanostructures receive immense research focus due to its high porosity, conductivity, and structural tailrolability features. In this work, porous Zeolitic Imidazole Framework‐67 (ZIF‐67) to synthesize cobalt phosphide/carbon composite (ZCoPC) that serves as a positive electrode is utilized. Furthermore, porous and conductive office paper derived carbon (OPC) are utilized as a negative electrode to make a hybrid system. The metalloid characteristics, high conductivity, and good porosity of ZCoPC material makes it a high‐performance battery like electrode. ZCoPC electrode achieves maximum specific capacity of 192.6 mAh g−1 at 1 A g−1 using 1 m potassium hydroxide (KOH) electrolyte. Furthermore, surface and diffusion charge participation investigation are also undergone for ZCoPC electrode that helps in determining the actual charge dynamics occurring in the electrode. In addition, a supercapattery device is assembled using ZCoPC as battery electrode and OPC as supercapacitor electrode. The as fabricated OPC//ZCoPC hybrid supercapattery device delivers extraordinary energy density of 31.6 Wh kg−1 with a power density of 700 W kg−1 and also a long cycle life of 92.3% even after 10,000 charge–discharge cycles. Hence, these outcomes demonstrate that the synergy of porous MOF derived metal phosphide and OPC electrodes are beneficial for supercapattery devices. [ABSTRACT FROM AUTHOR]

Transition metal phosphides are promising, selective, and air‐stable nanocatalysts for hydrogenation reactions. However, they often require fairly high temperatures and H2 pressures to provide quantitative conversions. This work reports the positive effect of phosphine additives on the activity of cobalt phosphide nano‐urchins for the semi‐hydrogenation of phenylacetylene. While the nanocatalyst's activity was low under mild conditions (7 bar of H2, 100 °C), the addition of a catalytic amount of phosphine remarkably increased the conversion, e. g., from 13 % to 98 % in the case of PnBu3. The heterogeneous nature of the catalyst was confirmed by negative supernatant activity tests. The catalyst integrity was carefully verified by post‐mortem analyses (TEM, XPS, and liquid 31P NMR). A stereo‐electronic map was proposed to rationalize the activity enhancement provided over a selection of nine phosphines: the strongest effect was observed for low to moderately hindered phosphines, associated with strong electron donor abilities. A threshold in phosphine stoichiometry was revealed for the enhancement of activity to occur, which was related to the ratio of phosphine to surface cobalt atoms. [ABSTRACT FROM AUTHOR]

Photocatalysts which are stable to photocorrosion and noble metal‐free, are highly desirable to achieve a light‐driven hydrogen production which satisfies the criteria of low production cost and environmental sustainability. Herein, a new heterostructure TiO2/BP/CoP has been developed, in which the BP nanosheets interact strongly with TiO2 and CoP, speeding up the transfer of photogenerated electrons and thus increasing H2 production. Once BP is added to TiO2 (P25) as only 1 % wt., the H2 evolution rate increases up to 4 times reaching a value of 830 μmol/g ⋅ h under UV‐Vis light irradiation. By integrating CoP nanoparticles as a cocatalyst up to 2 % wt., H2 production is further promoted to 7400 μmol/g ⋅ h, 37 times higher than pristine TiO2. Photoluminescence and electrochemical impedance measurements show that this heterostructure achieves a much more efficient charge separation and reduction of the internal resistance in comparison to pristine TiO2. Combining these data with UV‐Vis diffuse reflectance and Mott‐Schottky, a plausible mechanism was proposed. [ABSTRACT FROM AUTHOR]

In recent years, the elimination of organic pollutants using advanced oxidation processes (AOPs) based on peracetic acid (PAA) has drawn increasing attention due to the high oxidative potential and low byproducts. However, to explore more efficient and stable PAA‐based AOPs, there is still great room for study on the activation of PAA and degradation mechanism in the reaction process. In this study, a new PAA‐based AOP activated by metal–organic framework‐derived cobalt phosphide (CoP) and accompanied by chemiluminescence (CL) behaviour was explored. The CoP/PAA system could efficiently degrade 99.98% of RhB (20 mg L−1) within 5 min at pH 7 compared with the conventional Co3O4/PAA system (merely 17.29%), and the degradation process was matched well with the pseudo‐first‐order kinetic, and the kinetic constants was ~23.7 times higher than that of Co3O4 (0.546 min−1 for CoP vs. 0.023 min−1 for Co3O4). In the CoP/PAA/RhB process, the CL intensity was related to the concentration of 1O2, O2•– and acetyl peroxyl radicals [CH3C(O)OO• and CH3C(O)O•]. Therefore, CL analysis, combined with quenching tests and electron paramagnetic resonance analysis, was used to study the degradation mechanism in detail, and 1O2 was confirmed as the dominant contributor for the dye degradation. [ABSTRACT FROM AUTHOR]

Oil–water separation membranes easily fail to oil foulants with low surface energy and high viscosity, which severely limits these membranes' applications in treating oily wastewater. Herein, an oil–water separation membrane by bioinspired bubble‐mediated antifouling strategy is fabricated via growing hierarchical cobalt phosphide arrays on stainless steel mesh. The as‐prepared membrane is superhydrophilic/superaerophobic and electrocatalytic for hydrogen evolution under water, which helps to rapidly generate and release abundant microbubbles surrounding the oil‐fouled region on the membrane. These microbubbles can spontaneously coalesce with the oil foulants to increase their buoyancy and warp their interface tension by morphing the oil shape. And this spontaneous coalescence also increases the kinetic energy of oil foulants resulting from the decreased bubbles' interface energy and potential energy. The synergy of the warped interface tension, increased buoyancy, and kinetic energy drives the efficiently dynamic antifouling of this membrane. This dynamic antifouling even can remove some solid sediment such as oily sand particles that causes more serious fouling of the membrane. Thus, this membrane maintains high flux (>11920 L m−2 h−1 bar−1) in the long‐term separation of oil–water and oil–sand–water emulsions by dynamically recovering the decayed flux on demand, which exhibits great potential in treating industrial oily wastewater. [ABSTRACT FROM AUTHOR]

Concave nanostructure with highly branched architecture and abundant step atoms is one kind of desirable materials for energy conversion devices. However, current synthetic strategies for non‐noble metal‐based NiCoP concave nanostructure still remain challenging. Herein, we demonstrate a site‐selective chemical etching and subsequent phosphorating strategy to fabricate highly branched NiCoP concave nanocrosses (HB‐NiCoP CNCs). The HB‐NiCoP CNCs are consisted of six axial arms in three‐dimensional space and each protruding arm is equipped with high‐density atomic steps, ledges and kinks. As an electrocatalyst towards oxygen evolution reaction, the HB‐NiCoP CNCs exhibit remarkably enhanced activity and stability, with small overpotential of 289 mV to reach 10 mA cm−2, surpassing the NiCoP nanocages and commercial RuO2. The superior OER performance of HB‐NiCoP CNCs is originated from the highly branched concave structure, the synergistic effect between bimetal Ni and Co atoms, as well as the electronic structure modulation from P. [ABSTRACT FROM AUTHOR]

In this paper, using density functional theory (DFT) methods, we meticulously investigated the structural properties of cobalt phosphide (CoP) and its Cu‐ and Ni‐doped counterpart. Then, on the surfaces of three catalysts, the hydrogen evolution reaction mechanism of ammonia borane (NH3BH3) was examined in turn, and four possible hydrogen evolution reaction paths of NH3BH3 on the catalyst surface were reviewed. The optimal reaction channel for each catalyst was found by comparing the activation energies of the control steps for several reaction paths, and activation energies of the optimal reaction for CoP, Cu, and Ni‐doped CoP were 31.4, 30.4, and 30.8 kcal/mol, respectively. Cu‐ and Ni‐ doped were beneficial to improve the hydrogen evolution reaction activity of NH3BH3. At the same time, the band structures and density of states of the stable catalysts were calculated. The results showed that near the fermi level, the electron cloud density of Cu and Ni‐doped CoP catalysts increased. The energy gap values of the three catalysts are 43.8, 41.0, and 41.7 kcal/mol, respectively, and the energy gap values of Cu and Ni doped CoP catalysts decrease. The energy gap values of the three catalysts are inversely proportional to their catalytic activities. We believe that these two factors together contribute to the increased catalytic activity of the doped CoP. Our results revealed the correlation between the physical properties of CoP and its metal‐doped catalysts and their catalytic activity. [ABSTRACT FROM AUTHOR]

In this paper, using density functional theory (DFT) methods, we meticulously investigated the structural properties of cobalt phosphide (CoP) and its Cu‐ and Ni‐doped counterpart. Then, on the surfaces of three catalysts, the hydrogen evolution reaction mechanism of ammonia borane (NH3BH3) was examined in turn, and four possible hydrogen evolution reaction paths of NH3BH3 on the catalyst surface were reviewed. The optimal reaction channel for each catalyst was found by comparing the activation energies of the control steps for several reaction paths, and activation energies of the optimal reaction for CoP, Cu, and Ni‐doped CoP were 31.4, 30.4, and 30.8 kcal/mol, respectively. Cu‐ and Ni‐ doped were beneficial to improve the hydrogen evolution reaction activity of NH3BH3. At the same time, the band structures and density of states of the stable catalysts were calculated. The results showed that near the fermi level, the electron cloud density of Cu and Ni‐doped CoP catalysts increased. The energy gap values of the three catalysts are 43.8, 41.0, and 41.7 kcal/mol, respectively, and the energy gap values of Cu and Ni doped CoP catalysts decrease. The energy gap values of the three catalysts are inversely proportional to their catalytic activities. We believe that these two factors together contribute to the increased catalytic activity of the doped CoP. Our results revealed the correlation between the physical properties of CoP and its metal‐doped catalysts and their catalytic activity. [ABSTRACT FROM AUTHOR]

The high intermediate (H*, OH*) energy barriers and slow mass/charge transfer increase the overpotential of alkaline water electrolysis at large‐current‐density. Engineering the electronic structure with the morphology of the catalyst to reduce energy barriers and improve mass/charge transportation is effective but remains challenging. Herein, a Ce‐doped CoP nanosheet is hybrid with Ni3P@NF (Ni foam) support to enhance mass/charge transfer, tune energy barriers, and improve water‐splitting kinetics through a synergistic activation. The engineered Ce0.2‐CoP/Ni3P@NF cathode exhibits an ultralow overpotential (η500, η1000) of −185, and −225 mV at −500 and −1000 mA cm−2 in 1.0 m KOH, along with an excellent pH‐universality. Impressively, an electrolyzer using the Ce0.2‐CoP/Ni3P@NF cathode can afford 500 mA cm−2 at a cell voltage of only 1.775 V and maintain stable electrolysis for 200 h in 25 wt% KOH (50 °C). Characterization and density functional theory calculation further reveal the Ce‐doping and CoP/Ni3P hybrid interaction synergistically downshift d‐band centers (εd = −2.0 eV) of Ce0.2‐CoP/Ni3P to the Fermi level, thereby activate local electronic structure for accelerating H2O dissociation and optimizing Gibbs free energy of hydrogen adsorption (∆GH*). [ABSTRACT FROM AUTHOR]

A photoredox/cobalt dual catalytic procedure has been developed that allows benzoylation of olefins. Here the photoredox catalyst effects the decarboxylation of α‐ketoacids to form benzoyl radicals. After addition of this radical to styrenes, the cobalt catalyst abstracts a H‐atom. Hydrogen evolution from the putative cobalt hydride intermediate allows a Heck‐like aroylation without the need for a stoichiometric oxidant. Mechanistic studies reveal that electronically different styrenes lead to a curved Hammett plot, thus suggesting a change in product‐determining step in the catalytic mechanism. [ABSTRACT FROM AUTHOR]

Exploring a general method for synthesizing 2D compounds with high accessible surface area and nano‐thickness as advanced electrocatalysts is essential yet challenging. Herein, a self‐assembly induced reverse micelle templating method followed by topochemical transformation is developed to synthesize a series of cobalt‐based compounds with varied anions and similar ultrathin 2D structures. Electrocatalytic behaviors for the hydrogen evolution reaction (HER) are systematically investigated, which demonstrate enhanced performances of ultrathin 2D compounds than their agglomerated counterparts. Among them, 2D CoP is particularly prominent. The overpotential of 144 mV at 10 mA cm−2, together with superb stability, place it among the best single‐phase phosphide HER catalysts reported thus far. Theoretical calculation and experimental results demonstrate the favorable valence electronic structure with moderate hydrogen adsorbability and good intracrystalline conductivity, as well as the homogeneous ultrathin 2D configuration with sufficiently exposed active sites and shortened intracrystalline electron transport route, are the dominant reasons that 2D CoP exhibits optimal electrocatalytic activity for HER. This study presents a novel and extendable strategy for synthesizing various 2D metal‐based compounds with valuable insights into the modulation essence of advanced electrocatalysts. [ABSTRACT FROM AUTHOR]

A hierarchically ordered porous carbon electrocatalyst with exclusively surface‐anchored cobalt species, dubbed Co@HOPC, is synthesized from polyaniline and cobalt‐functionalized silica microparticles templates, and its high electrocatalytic activity for the oxygen evolution reaction (OER) is demonstrated. The material requires a small potential (320 mV) to drive the reaction with a current density of 10 mA cm−2 and a small Tafel slope of 31.2 mV dec−1. Moreover, Co@HOPC shows better catalytic activity for OER than in situ cobalt‐doped and surface cobalt‐loaded hierarchically ordered porous carbon materials synthesized by traditional methods. This is due to the abundant surface cobalt species present in Co@HOPC and the material's good electrical conductivity. This work provides a new strategy to utilize functionalized silica microparticles as templates to synthesize hierarchically ordered porous carbon materials with metal‐rich surfaces and efficient electrocatalytic activities. [ABSTRACT FROM AUTHOR]

Designing a stable and efficient dual‐functional catalyst for the hydrogen evolution and oxygen evolution reactions (HER/OER) is of great significance to the development of hydrogen production by water splitting. This work reports on novel halogen (X = F, Cl, and Br)‐doped carbon dots modifying amorphous cobalt phosphide (X‐CDs/CoP), which can be tuned by the choice of X‐CDs to have urchin, Pinus bungeana, and Albizia julibrissin type structures. The different characteristics of the various X‐CDs led to different formation mechanisms and final structures. As a bifunctional catalyst, urchin‐shaped F‐CDs/CoP crystals achieve superior electrocatalytic performance, exhibiting excellent HER/OER activity and sustained stability in an alkaline solution. For overall water splitting, they provide current density of 10 mA cm−2 and require a low cell voltage of 1.48 V in 1 M KOH. In addition, the catalytic performance shows negligible degradation after 100 h, thus demonstrating excellent long‐term cycling stability. Density functional theory calculations show that the improved electrocatalytic performance of F‐CDs/CoP catalysts is due to the coupling interface between CoP and F‐CDs, which optimizes the hydrogen/oxygen adsorption energy and accelerates the water splitting kinetics. This work provides guidance for the rational design of transition metal phosphide electrocatalysts with outstanding performance. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries have aroused great interest in the context of rechargeable batteries, while the shuttle effect and sluggish conversion kinetics severely handicap their development. Defect engineering, which can adjust the electronic structures of electrocatalyst, and thus affect the surface adsorption and catalytic process, has been recognized as a good strategy to solve the above problems. However, research on phosphorus vacancies has been rarely reported, and how phosphorus vacancies affect battery performance remains unclear. Herein, CoP with phosphorus vacancies (CoP‐Vp) is fabricated to study the enhancement mechanism of phosphorus vacancies in Li–S chemistry. The derived CoP‐Vp features a low Co‐P coordination number and the introduced phosphorus vacancies mainly exist in the form of clusters. The obtained CoP‐Vp can reinforce the affinity to lithium polysulfides (LiPSs) and thus the shuttle effect can be restrained. In addition, the reduced reaction energy barriers and the promoted diffusion of Li+ can accelerate redox kinetics. Electrochemical tests and in situ Raman results confirm the advantages of phosphorus vacancies. The S/CNT‐CoP‐Vp electrode presents outstanding cycling performance and achieves a high capacity of 8.03 mAh cm−2 under lean electrolyte condition (E/S = 5 μLE mg−1S). This work provides a new insight into improving the performance of Li–S batteries through defect engineering. [ABSTRACT FROM AUTHOR]

Seawater electrolysis under alkaline conditions presents an attractive alternative to traditional freshwater electrolysis for mass sustainable high‐purity hydrogen production. However, the lack of active and robust electrocatalysts severely impedes the industrial application of this technology. Herein, carbon‐doped nanoporous cobalt phosphide (C‐Co2P) prepared by electrochemical dealloying is reported as an electrocatalyst for hydrogen evolution reaction (HER). The C‐Co2P achieves an overpotential of 30 mV at a current density of 10 mA cm−2 in 1 m KOH, along with impressive catalytic activity and stability at large current densities in artificial alkaline seawater electrolyte containing mixed chlorides of NaCl, MgCl2, and CaCl2. Experimental analysis and density functional theory calculations reveal that the C atom with strong electronegativity and small atomic radius can tailor the electronic structure of Co2P, leading to weakened Co–H bonding toward promoted HER kinetics. Moreover, the C doping introduces a two‐stepped H delivery pathway by forming C–Had intermediate, thus reducing the energy barrier of water dissociation. This study offers a new vision toward the development of seawater electrolysis for large‐scale hydrogen production. [ABSTRACT FROM AUTHOR]

Cobalt phosphide (CoP) has been demonstrated as a cocatalyst for visible‐light‐sensitized CO2 reduction, but just with moderate selectivity, due to the competitive H2 generation reaction. Herein, the porous N‐doped carbon (NC) layer is in situ coated on the surface of CoP nanoparticles to fabricate the core‐shell CoP@NC composite cocatalyst. Benefiting from the outstanding electric conductivity and high surface area of the NC shell, the CoP@NC hybrid attains strengthened capabilities for charge separation/transfer and CO2 capture/activation. Besides, the direct contact of CoP with H2O is prevented by the porous NC shell with high hydrophobicity. Consequently, the photosensitized CO2‐to‐CO conversion efficiency and selectivity of CoP@NC hybrid are enhanced by 2.7 and 2.4 times, respectively, compared to bare CoP. [ABSTRACT FROM AUTHOR]

Electrocatalysis is a potential method for sustainable hydrogen production, and the development of non‐noble metal‐based effective electrocatalysts for electrochemical water splitting is the core of exploiting and utilizing renewable energy. Herein, a stupendous electrocatalyst with multiheterostructure interfaces and 3D porous structure is synthesized, and the mechanisms of enhanced electrocatalytic activity combining multicharacterizations and density functional calculations are clarified. Especially, the fabricated Co2P/N@Ti3C2Tx@NF (denoted as CPN@TC) exhibits an ultralow overpotential of 15 mV to arrive at a current density of 10 mA cm−2 with the long‐term durability and a small Tafel slope of 30 mV dec−1 in 1 m KOH, which even compares with noble metal catalysts favorably. The outstanding HER activity is ascribed to multiheterointerfaces for adsorbing H2O and H*, fine conductivity for the electronic transmission, and well‐designed structure for rapid transport of ions and gases. It is reasonable to think that the synthetic strategy of CPN@TC can be extended to the preparation of transition‐metal‐based phosphides for enhanced catalytic performance. [ABSTRACT FROM AUTHOR]

Catalysts based on earth‐abundant non‐noble metals are interesting candidates for alkaline water electrolysis in sustainable hydrogen economies. However, such catalysts often suffer from high overpotential and sluggish kinetics in both the hydrogen and oxygen evolution reactions (HER and OER). In this study, a hybrid catalyst made of iron‐doped cobalt phosphide (Fe‐CoP) nanowire arrays and Ni(OH)2 nanosheets is introduced that displays strong electronic interactions at the interface, which significantly improves the interfacial reactivity of reactants and/or intermediates with the hybrid catalyst surface. The combined experimental and theoretical study further confirms that the hybrid catalyst promotes the sluggish rate‐limiting steps in both the HER and OER. Full water electrolysis is thus enabled to take place at such a low cell voltage as 1.52 V to reach the current density of 10 mA cm−2 along with superior durability and high conversion efficiency. [ABSTRACT FROM AUTHOR]

Phosphorus-rich transition metal phosphides (TMPs) are considered efficient electrocatalysts for the hydrogen evolution reaction (HER). However, the actual activity of P-rich TMPs is not as good as expected because of the undesirable electronic structure. Transition metal doping has been shown to be effective in improving the HER activity of TMPs in both acid and alkaline media, but the underlying mechanism is ambiguous, especially for P-rich TMPs. Herein, cobalt-doped and phosphorus-rich tungsten phosphide nanowire arrays (Co/WP2 NWs/CC) are synthesized and the electrochemical properties and mechanism are determined by both experiments and theoretical calculation. The results reveal that Co dopants serve as inert catalytic sites and do not participate in HER process, but the Co/WP2 NWs/CC exhibits enhanced electrocatalytic activity as a result of the lower water dissociation barrier and hydrogen adsorption/desorption free energy on W or P sites and improved conductivity by strong electron-donating effects of Co dopants, thereby boosting the catalytic activity and kinetics. [ABSTRACT FROM AUTHOR]

Transition metal phosphides have been recognized as efficient co‐catalysts to boost the activity of semiconductor photocatalysts. However, a rigorous and quantitative understanding is still to be developed about how transition metal phosphides influence photoexcited electron dynamics. Here, we present a nanosecond time‐resolved transient absorption spectroscopy (TAS) study of the photoexcited electron dynamics in carbon nitrides (g‐C3N4) before and after Co and/or P modifications. Our spectroscopic study showed that Co or P lowered the initial electron density, whereas they promoted the photoexcited electron relaxation of g‐C3N4, with their half‐life times (t50%) of 2.5 and 1.8 ns, respectively. The formation of a CoP co‐catalyst compound promoted the electron relaxation (t50%=2.8 ns) without significantly lowering the charge separation efficiency. Density functional theory (DFT) calculations were undertaken to explore the underlying fundamental reasons and they further predicted that CoP, compared to Co or P modification, better facilitates photoexcited electron transfer from g‐C3N4 to reactants. [ABSTRACT FROM AUTHOR]

Atowar Rahman M. B Enhancing the photovoltaic performance of Cd-free Cu b SB 2 sb B ZnSnS b SB 4 sb B heterojunction solar cells using SnS HTL and TiO2 ETL. b I Solar Energy i 2021; B 215 b : 64-76. de Amorim Soares G, Carolus J, Daenen M, et al. B Round-robin of damp heat tests using CIGS solar cells. b I Solar Energy i 2021; B 214 b : 393-399. REVIEWS, FUNDAMENTALS AND NEW APPROACHES GENERAL CHARACTERISATION TECHNIQUES AND MODELLING Shimizu Y, Sai H, Matsui T, et al. B Crystallite distribution analysis based on hydrogen content in thin-film nanocrystalline silicon solar cells by atom probe tomography. b I Applied Physics Express i 2021; B 14 b (1): 016501. Liu Y, Pomaska M, Duan WY, et al. B Phosphorus catalytic doping on intrinsic silicon thin films for the application in silicon heterojunction solar cells. b I Acs Applied Materials and Interfaces i 2020; B 12 b (50): 56615-56621. Heitmann U, Bartsch J, Kluska S, et al. B Pathways and potentials for III-V on Si tandem solar cells realized using a ZnO-based transparent conductive adhesive. b I IEEE Journal of Photovoltaics i 2021; B 11 b (1): 85-92. [Extracted from the article]

Photocatalytic CO2 conversion is a promising method to yield carbon fuels, but it remains challenging to regulate catalytic materials for enhanced reaction efficiency and tunable product selectivity. This study concerns the development of a facile and efficient thermal post‐treatment method to improve the crystallinity and surface hydrophobicity of a cobalt phosphide (CoP) cocatalyst, which promotes the separation and transfer of photoexcited charge carriers, reinforces CO2 chemisorption, and weakens the H2O affinity. Compared with pristine CoP, the optimal CoP‐600 cocatalyst displays a 3.5‐fold enhancement in activity and a 2.3‐fold increase in selectivity for the reduction of CO2 to CO with a high rate of 68.1 μmol h−1. [ABSTRACT FROM AUTHOR]

In this work, we report the template‐free synthesis of zinc cobalt oxides/phosphides (Co2P/CoO/ZnCo2O4) hollow sub‐micron boxes as electrocatalysts for HER (hydrogen evolution reaction). The synthesis of such sub‐micron box starts with the preparation of the hollow oxide sub‐micron box and is followed by a phosphorization process. It is proven that the selective etching induces by cation exchange (Zn2+ and Co2+) was the key to the formation of the hollow structure. The analysis of chemical states and electrochemical activity further reveals Zn enhanced the intrinsic activity of catalysts by increasing the electron density of Co in final products. The optimized ZnCo‐OP hollow sub‐micron box exhibits good HER activity with overpotentials of 112 mV at 10 mA/cm2 and 197 mV at 250 mA/cm2. [ABSTRACT FROM AUTHOR]

Urchin‐type cobalt phosphide microparticles assembled by nanorod were encapsulated in a graphene framework membrane (CoP@GF), and used as a binder‐free electrode for alkali metal ion batteries. Electrochemical measurements indicate that this membrane exhibits enhanced reversible lithium, sodium, and potassium storage capabilities. Moreover, the energy storage properties of CoP@GF electrodes in alkali metal ion batteries display an order of Li>Na>K. DFT calculations on adsorption energy of CoP surfaces for Li, Na, and K indicated that CoP surfaces were more favorable to transfer electrons to Li atoms than Na and K, and the surface reactivity can be ordered as Li‐CoP>Na‐CoP>K‐CoP; thus, CoP@GF exhibits better storage capacity for lithium. This work provides experimental and theoretical basis for understanding the electrochemical performance of cobalt phosphide‐based membranes for alkali metal ion batteries. [ABSTRACT FROM AUTHOR]

Electrocatalytic water splitting is considered an attractive way to achieve clean and sustainable energy production. Herein, a series of self‐supported oxygen and molybdenum dual‐doped cobalt phosphides grown on Ni foam (O,Mo−CoP/NFs) were prepared. The O,Mo−CoP/NFs exhibited 3D hierarchical morphologies including urchin‐like nanostructures assembled with nanorods and nanoflowers assembled with ultrathin nanosheets. The optimized O,Mo−CoP/NFs‐2 nanoflowers exhibited superior electrocatalytic performance for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with an overpotential of only 59 mV at 10 mA cm−2 for HER and 301 mV overpotential at 100 mA cm−2 for OER. Moreover, the O,Mo−CoP/NFs‐2 nanoflowers exhibited efficient overall water splitting as low as 1.66 V for 100 mA cm−2 with outstanding long‐term stability, even superior to the commercial Pt−C/NF and RuO2/NF system. The superior activity of self‐supported O,Mo−CoP/NFs‐2 nanoflowers was attributed to the synergistic effect of O and Mo dual doping, which promoted its intrinsic catalytic activity, and its particular morphology of self‐supported 3D hierarchical nanoflowers, which could expose more catalytic sites and enable facile gas escape. Moreover, the device of overall water splitting can be powered by a single AA battery or a 1.5 V solar cell, showing its great potential for practical applications. [ABSTRACT FROM AUTHOR]

Developing efficient metal sulfides for pure water splitting is a challenging topic in the field of photocatalysis. Herein, inspired by natural photosynthesis, an all‐solid‐state Z‐scheme photocatalyst was constructed with Cd0.9Zn0.1S (CZS) for water reduction, red phosphorus (RP) for water oxidation, and metallic CoP as the electron mediator. RP@CoP core‐shell nanostructures were uniformly attached on the CZS nanorods, which gave rise to multiple monodispersed nanojunctions. The integrated Z‐scheme nanosystem exhibited an apparent quantum efficiency of 6.4 % at 420 nm for pure water splitting. Theoretical analysis and femtosecond transient absorption results revealed that the impressive performance was mainly due to efficient hole transfer of CZS, resulting from the intimate atomic contacts between CoP mediator and photocatalysts, together with favorable band alignment. Meanwhile, the multiple monodispersed Z‐scheme nanojunctions could provide abundant reaction sites, which was also important for the boosted activity. [ABSTRACT FROM AUTHOR]

Efficient and low‐cost bifunctional OER/HER electrocatalysts are important for overall water splitting. Herein, three‐dimensional self‐supported Fe‐doped NiCo‐based phosphide nanosheets arrays are in‐situ grown on carbon fiber paper. The catalyst shows superior bifunctional activity, with an OER overpotential of 230 mV and an HER overpotential of 95 mV at 10 mA cm−2 in alkaline electrolyte. It is evidenced that the Fe doping facilitates electron transfer from Co/Ni to P, thus optimizing the electronic structures of both Ni and Co active sites, in turn greatly enhancing intrinsic OER and HER activities. The OER and HER turnover frequency are largely improved after Fe doping. When used as both anode and cathode for water splitting, the catalyst enables the electrolyzer to achieve 10 mV cm−2 at a low cell voltage of 1.59 V with a long‐term stability up to 35 h. This work highlights the synergy effect of multi‐metal‐based phosphides for efficient water electrocatalysis. [ABSTRACT FROM AUTHOR]

Hydrogen evolution reaction (HER) from water electrolysis is an attractive technique developed in recent years for clean renewable energy. It is critical to develop a low‐cost, high activity and long‐time stability HER catalyst. In this work, a novel catalyst, Cobalt‐Molybdenum bimetal phosphides encapsulated in carbon matrix (Co‐Mo‐P@C), is synthesized using MOFs‐templated strategy by chemical vapor deposition (CVD) and phosphidation. The Co‐Mo‐P@C catalyst exhibits excellent catalytic performances with low overpotentials of 148 and 159 mV to reach current densities of 10 mA cm−2 for HER in both acidic and alkaline media, respectively, as well as long‐time durability over 20 h. This work introduces a new method for an efficient and stable HER catalyst and it may be extended to design other encapsulated bimetal nitrides, sulfides, and selenides for more applications. [ABSTRACT FROM AUTHOR]

Superstructures have attracted great interest owing to their potential applications. Herein, we report the first scalable preparation of a porous nickel‐foam‐templated superstructure of carbon nanosheets decorated with ultrafine cobalt phosphide nanoparticles. Uniform two‐dimensional (2D) Co‐metal organic framework (MOF) nanosheets (Co‐MNS) grow on nickel foam, followed by a MOF‐mediated tandem (carbonization/phosphidation) pyrolysis. The resulting superstructure has a porous 3D interconnected network with well‐arranged 2D carbon nanosheets on it, in which ultrafine cobalt phosphide nanoparticles are tightly immobilized. A single piece of this superstructure can be directly used as a self‐supported electrode for electrocatalysis without any binders. This "one‐piece" porous superstructure with excellent mass transport and electron transport properties, and catalytically active cobalt phosphide nanoparticles with ultrasmall size (3–4 nm), shows excellent trifunctional electrocatalytic activities for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR), achieving great performances in water splitting and Zn–air batteries. [ABSTRACT FROM AUTHOR]

The highly active spherical hybrid catalysts with diameters of 3–8 μm for robust selective CO2 photoreduction and hydrogen production by switching solvent, CoP/(i)s‐SBA‐15 and CoP/(o)s‐SBA‐15, were in situ synthesized for the first time by incorporating CoP nanoparticles on the interior and outside of the spherical mesoporous Santa Barbara Amorphous (s‐SBA)‐type material s‐SBA‐15. CoP/(i)s‐SBA‐15 has a larger pore diameter of ∼9.5 nm, relative to ∼5.7 nm of CoP/(o)s‐SBA‐15, and a calculated Brunauer‐Emmett‐Teller surface area of ∼214 m2 g−1 compared with ∼336 m2 g−1 for the latter. In comparison with bare CoP, the composites exhibited excellent catalytic CO‐ and H2‐generating performance with product selectivity of up to 76.3 % and 99.9 % through switching solvents containing Ru‐based photosensitizer under ambient conditions, respectively. The influences of various solvents and electron donors, as well as the amounts of H2O, and catalyst on reaction kinetics for CO2 reduction and H2 production, and intrinsic properties of both catalysts were investigated and compared. [ABSTRACT FROM AUTHOR]

Interfacial engineering and defect modulation can provide abundant active sites for catalysts to further boost the catalysis process. In this work, we develop a strategy to grow multi‐heterogeneous cobalt phosphide (CoP) nanorods with rich interfaces and defects along the one‐dimensional (1D) nanostructure by dual incorporation of Fe and Ru (CoFeP@Ru). Such a catalyst exhibits high activity and stability towards the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with overpotentials of only 38 mV in 0.5 M H2SO4 and 48 mV in 1.0 M KOH for HER, and an overpotential of 340 mV in 0.1 M KOH for OER at 10 mA cm−2. Finally, as the bifunctional catalyst, an alkali electrolyzer is assembled and delivers at a low cell voltage, with almost 100 % Faradaic efficiency. Our experimental results demonstrate that Fe incorporation can disturb or even break the periodic structure of cobalt phosphides, causing a redistribution of the electronic structure and electron density of activity sites, while Ru can significantly enhance the catalytic kinetics, as well as electrochemical and mechanical stability. [ABSTRACT FROM AUTHOR]

Transition‐metal phosphides (TMP) prepared by atomic layer deposition (ALD) are reported for the first time. Ultrathin Co‐P films were deposited by using PH3 plasma as the phosphorus source and an extra H2 plasma step to remove excess P in the growing films. The optimized ALD process proceeded by self‐limited layer‐by‐layer growth, and the deposited Co‐P films were highly pure and smooth. The Co‐P films deposited via ALD exhibited better electrochemical and photoelectrochemical hydrogen evolution reaction (HER) activities than similar Co‐P films prepared by the traditional post‐phosphorization method. Moreover, the deposition of ultrathin Co‐P films on periodic trenches was demonstrated, which highlights the broad and promising potential application of this ALD process for a conformal coating of TMP films on complex three‐dimensional (3D) architectures. [ABSTRACT FROM AUTHOR]

Halide perovskite like methylammonium lead iodide perovskite (MAPbI3) with its prominent optoelectronic properties has triggered substantial concerns in photocatalytic H2 evolution. In this work, to attain preferable photocatalytic performance, a MAPbI3/cobalt phosphide (CoP) hybrid heterojunction is constructed by a facile in situ photosynthesis approach. Systematic investigations reveal that the CoP nanoparticle can work as co‐catalyst to not only extract photogenerated electrons effectively from MAPbI3 to improve the photoinduced charge separation, but also facilitate the interfacial catalytic reaction. As a result, the as‐achieved MAPbI3/CoP hybrid displays a superior H2 evolution rate of 785.9 µmol h−1 g−1 in hydroiodic acid solution within 3 h, which is ≈8.0 times higher than that of pristine MAPbI3. Furthermore, the H2 evolution rate of MAPbI3/CoP hybrid can reach 2087.5 µmol h−1 g−1 when the photocatalytic reaction time reaches 27 h. This study employs a facile in situ photosynthesis strategy to deposit the metal phosphide co‐catalyst on halide perovskite nanocrystals to conduct photocatalytic H2 evolution reaction, which may stimulate the intensive investigation of perovskite/co‐catalyst hybrid systems for future photocatalytic applications. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate morphology‐controlled synthesis of flower‐like cobalt phosphide decorated on nitrogen doped reduced graphene oxide (NrGO), which act as bifunctional electrocatalysts toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The as‐synthesized CoP‐NrGO, formed via hydrothermal reaction followed by gas‐solid reaction, attains an OER current density of 10 mA cm−2 at an overpotential of 0.38 V, which is on par with that of its Co(OH)2‐NrGO counterpart and the benchmarked IrO2 catalyst. On the other hand, the conversion of Co(OH)2 to CoP is seen to improve its HER performance drastically. CoP‐NrGO reached a current density of 10 mA cm−2 at an overpotential of 0.184 V which is 0.204 V anodic to Co(OH)2‐NrGO. The improved performance could be attributed to reduced charge transfer resistance following the phosphidation process. From the comparison of the electrocatalytic performance of the catalysts, it can be inferred that phosphidation has a considerable effect only on the cathodic HER. [ABSTRACT FROM AUTHOR]

The synthesis of nickel cobalt oxide materials and their electrocatalytic performance toward the oxygen reduction and evolution reactions are reported. Nickel cobalt oxides were synthesized in a sol‐gel process with different precursors, namely nitrate, sulfate, and chloride. Structural analyses show that the structures have mesoporous morphologies and indicate the formation of nickel cobalt oxide spinel structures with a size ranging from 35 to 65 nm. Furthermore, the physicochemical properties differ depending on the nature of the selected precursors, including the materials' morphology and the chemical composition. Electrocatalytic investigations demonstrate that the catalytic activity toward the oxygen reduction reaction (ORR) could be modulated between two‐ and four‐electron pathways, depending on the precursors used. The Cl−NiCoO sample displays a selective two‐electron reduction of O2, with H2O2 production higher than 90 %. The sample prepared using sulfate displays the highest performance toward the oxygen evolution reaction (OER), with a low overpotential value (0.34 V) to drive a current density of 10 mA.cm−1. Overall, these results confirm that the chemical composition of the precursor used during the nanomaterials synthesis can be used to tune the electrocatalytic performances toward ORR and OER. [ABSTRACT FROM AUTHOR]

Designing core‐shell heterostructures is essential for electrocatalytic hydrogen evolution reaction (HER). In this study, ultrathin MoS2 sheets are uniformly anchored on CoxP/nitrogen dual‐doped carbon nanocubes (CoxP/NC) through a template sacrificial method followed by a hydrothermal reaction. The resultant hybrid CoxP/NC@MoS2 possesses a core‐shell structure and superior catalytic activity to individual counterparts. The hybrid catalyst needs a low overpotential of 148 mV to drive the current density of 10 mA cm−2, together with an extremely small Tafel slope of 33 mV dec−1 and outstanding stability in acidic media. Most importantly, the best catalytic activity is achieved by coupling MoS2 nanosheets with the matrix CoxP/NC rather than Co/NC. The remarkably high HER activity of CoxP/NC@MoS2 mainly benefits from the core‐shell feature and strong synergistic interaction between CoxP/NC and MoS2. The present study inspires a continuous exploration of engineering MoS2 nanosheets on nanostructured metal phosphides for electrochemical applications. [ABSTRACT FROM AUTHOR]