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Development of low-cost, efficient, and stable oxygen evolution electrocatalysts is crucial for the conversion and storage of renewable energy. Therefore, an effective integrated heterostructure catalyst is needed to achieve a lower overpotential during oxygen evolution process. In this paper, cobalt-zinc bimetallic MOF precursors are used as templates to prepare bimetallic cobalt-based selenides with good oxygen evolution catalytic activity and stability on carbon fiber paper. Due to the high specific surface area and porous structure of the coupling structure of nanorods and polyhedra, and the strong electronic coupling between CoSe 2 and ZnSe on nanorods. CoSe 2 -ZnSe/CP exhibits excellent electrocatalytic activity in 1 M KOH solution. It only requires an overpotential of 275 mV to reach the current density of 10 mA cm-2, and the Tafel slope is 68.9 mV dec-1. In addition, after 12 h of continuous operation of CoSe 2 -ZnSe/CP, the activity decay of the catalyst is negligible. This work provides a method for the design of heterogeneous bimetallic selenide integrated oxygen evolution electrocatalysts. [Display omitted] • The CoSe 2 -ZnSe/CP catalyst is obtained by selenization of MOF precursor at high temperature. • The catalyst has unique nanorod-coupled polyhedral morphology and high specific surface area. • The strong electron coupling between CoSe 2 and ZnSe improves the oxygen evolution activity. • CoSe 2 -ZnSe/CP exhibits low overpotential, high exchange current density and fast kinetics. [ABSTRACT FROM AUTHOR]

Ni-doped WC/Mo 2 C composites for hydrogen evolution reaction (HER) were synthesized in situ grown on carbon fiber paper (CFP) by molten salt method in argon at 1000 °C for 6 h, named as Ni-xWC-y/2Mo 2 C@CFP. The effects of different W/Mo molar ratios (3:1, 2:1, 1:1, 1:2, 1:3) on the phase composition, microstructures, and HER performances were investigated. The results showed that the W/Mo molar ratio had a synergistic effect in HER of Ni-doped WC/Mo 2 C composites, and as W/Mo molar ratio at 1:1, the composite presented the best electrocatalytic activity. Meanwhile, its surface appeared to have a wrinkle-like structure, and the biphasic heterostructure emerged at the intersection of the dual-phase WC and Mo 2 C lattices. The introduction of a biphasic heterostructure could promote charge transfer and improve HER efficiency. Predictably, the electrocatalysts with the optimal W/Mo molar ratio 1:1 exhibited the best hydrogen evolution performance, needed only 43.7 mV overpotential to reach 10 mA cm−2 current density with a Tafel slope at 21.3 mV dec−1. In this work, the high-efficiency electrocatalysts of Ni-doped 1WC-1/2Mo 2 C@CFP have been prepared, which provides an insight into theoretical research of composite carbon-based electrocatalysts. [ABSTRACT FROM AUTHOR]

Integrating more active components into a catalyst material could facilitate the development of multifunctional electrocatalysts for energy conversion and storage applications. In this study, we developed a multifunctional electrocatalyst, namely, Pd alloyed with Co-Fe deposited on N-doped mesoporous carbon derived from tissue paper (Pd@Co-Fe/N-TDC). The synergism in Pd@Co-Fe/N-TDC, stemming from the interatomic alloy between Pd and Co-Fe, N-doped mesoporous carbon with defective surfaces, distribution of polyhedral Pd nanoparticles, and strong metal-support interfacial interaction, resulted in significantly high electrocatalytic performance for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Pd@Co-Fe/N-TDC was found to be an efficient bifunctional oxygen electrocatalyst, and this was evidenced by a high onset potential (1.01 V) and kinetic current density (2.6 mA/cm2) for the ORR and by a low overpotential (296 mV) and a low Tafel slope value (38 mV/dec) for the OER, along with a small Δ E of 736 mV. The catalyst also exhibited high durability for both ORR and OER, even after 10000 and 5000 cycles, respectively. Theoretical assessment provides an insight into the synergism of active metal sites in Pd@Co-Fe/N-TDC, which showed its potential for use as a non-Pt electrocatalyst for energy applications. [ABSTRACT FROM AUTHOR]

NiFe2O4 material is grown on carbon paper (CP) with the hydrothermal method for use as electrocatalysts in an alkaline electrolyzer. NiFe2O4 material is used as the anode and cathode catalysts (named NiFe(+)/NiFe(−) hereafter). The results are compared with those obtained using CP/NiFe as the anode and CP/Ru as the cathode (named NiFe)(+)/Ru(−) hereafter). During cell operation with NiFe(+)/Ru(−), the current density reaches 500 mA/cm2 at a cell voltage of 1.79 V, with a specific energy consumption of 4.9 kWh/m3 and an energy efficiency of 66.2%. In comparison, for NiFe(+)/NiFe(−), the current density reaches 500 mA/cm2 at a cell voltage of 2.23 V, with a specific energy consumption of 5.7 kWh/m3 and an energy efficiency of 56.6%. The Faradaic efficiency is 96–99%. With the current density fixed at 400 mA/cm2, after performing a test for 150 h, the cell voltage with NiFe(+)/Ru(−) increases by 0.167 V, whereas that with NiFe(+)/NiFe(−) decreases by only 0.010 V. Good, long-term stability is demonstrated. [ABSTRACT FROM AUTHOR]

Electrochemical oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) has received increasing attention as it is an eco-friendly strategy for synthesizing a key monomer for the production of bio-based plastics. Developing efficient, low-cost and stable electrocatalysts is crucial for this electrochemical reaction. In this work, we have reported a facile process for the synthesis of hybrid nanosheet-structured NiCo2O4 on carbon fiber paper (NiCo2O4-CFP) for the efficient electrochemical conversion of HMF into FDCA. As a non-noble binary metal-based catalyst, NiCo2O4-CFP featured a nanosheet network and 3D nanosheet flower-like microspheres, showing 94.3% selectivity and 89.6% faradaic efficiency (FE) for FDCA, which outperformed its single component metal oxides NiO-CFP and Co3O4-CFP. And it also exhibited relatively high stability by maintaining over 80% FE after four successive cycles. The proposed mechanism suggested that the synergistic effect of Ni and Co elements in NiCo2O4 could facilitate HMF oxidation. [ABSTRACT FROM AUTHOR]

Transition metal–based catalysts are considered to be promising materials to replace noble metal catalysts for electrocatalytic water splitting. Herein, a flexible electrode composed of Co-Ni-P ternary catalysts and carbon fiber paper substrate (Co-Ni-P/CFP) was successfully fabricated and applied in water electrolysis. The Co-Ni-P coatings were deposited on CFP by a one-step cyclic voltammetric electrodeposition method and the surface of the composite material exhibits nano-reticular structure. The formation mechanism was also discussed according to the results of material characterization. Notably, the Co-Ni-P/CFP flexible electrode exhibited superior catalytic performance for both hydrogen and oxygen evolution reactions in alkaline media, which could achieve 10 mA/cm2 current density with overpotential of 89 mV for HER and 320 mV for OER. Moreover, the Co-Ni-P/CFP electrode could also be used as both anode and cathode electrode to drive overall water splitting and required only 1.64 V to achieve a current density of 10 mA/cm2, which was very close to that of the commercial combination of Pt/C and IrO2. This affordable and easily obtained electrode offers a new avenue to develop earth-abundant resource catalysts for water electrolysis system. [ABSTRACT FROM AUTHOR]

The development of greatly stable and cost-effective electrocatalysts for urea electro-oxidation reactions (UERs) is urgent and challenging for promoting urea removal in the wastewater and advanced energy conversion devices. We demonstrated that nickel-iron borate (NiFe-B) electrocatalysts supported on carbon paper (CP) for UERs through a one-pot solvothermal method. NiFe-B electrocatalysts were obtained with numerous Ni/Fe molar ratios in the precursors, and the physicochemical features of the NiFe-B were examined by X-ray diffraction, scanning and transmission electron microscope, and X-ray photoelectron spectroscopy. The optimized NiFe-B/CP exhibited a low onset potential (E onset = 0.287 V vs. SCE) with a Tafel slope of 27.9 mV/dec on CP, demonstrating much greater performance UERs. Furthermore, the NiFe-B/CP catalysts have shown a superior activity for the UERs in alkaline solution and exhibit more than two-fold enhancement in activity than Ni-B. Facile, cost-effective fabrication and highly efficient urea oxidation create the NiFe-B electrodes as attractive materials for UERs. [Display omitted] • Amorphous Ni-Feborate/CP fabricated via facile hydrothermal process. • NiFe-B-2/CP electrode materials exhibited a lower onset potential with an overpotential of 327 mV at 10 mA cm−2. • Mass activities of NiFe-B-2/CP electrode materials reach up to 51.7 A/g. • NiFe-borate materials are a promising candidate for efficient electrocatalytic reactions. [ABSTRACT FROM AUTHOR]

Synthesis of affordable electrocatalysts with high efficiency at low cost is crucial for large-scale water splitting. Molybdenum carbide (Mo 2 C) has been suggested to be a promising alternative to noble metal based electrocatalysts for water splitting. In this paper, we fabricated a nanotextured coating of wrinkled Ni-doped Mo 2 C on carbon fiber paper (CFP) from Ni, Mo and carbon black (CB) via a molten salt method. Such a novel electrocatalyst, denoted as Ni-Mo 2 C CB /CFP, shows an overpotential of 121.4, 209.3 and 426.4 mV to achieve a current density of 10, 20 and 50 mA cm−2 respectively in acidic medium. The hydrogen evolution reaction (HER) performance of other as-prepared CFP based electrodes (bare CFP, Mo 2 C/CFP, Mo 2 C CB /CFP, Ni-Mo 2 C/CFP and NiC x /CFP) also tested. We found that the addition of carbon black and the doping of Ni could significantly improve the electrocatalytic performance of Mo 2 C/CFP in terms of overpotential, Tafel slope and exchange current density. This work demonstrates a facile and scalable route using molten salt method for the synthesis of high-performance electrocatalysts from non-precious compounds on carbon materials. Image 1 • Carbon fiber paper (CFP) was employed as a carbon source and substrate of Mo 2 C. • The addition of carbon black (CB) contributes to the refinement of Mo 2 C particles. • Ni-Mo 2 C/CFP composite was prepared from Ni, Mo, CFP and CB by a molten salt method. • The Ni-Mo 2 C/CFP electrocatalyst exhibits excellent catalytic performance for HER. [ABSTRACT FROM AUTHOR]

We report a type of transition metal selenide (Fe40Co40Se20) thin films supported on carbon fiber paper (CFP) (Fe40Co40Se20/CFP) and study the effects of the substrate temperature during thin film deposition on the electrocatalytic performance of the films in the oxygen evolution reaction. Fe40Co40Se20/CFP thin films were deposited by vacuum magnetron sputtering at substrate temperatures of 308, 393, and 573 K. In 1MKOH, the amorphous film deposited at 393 K exhibited better comprehensive electrocatalytic activity and stability than that of the Fe40Co40Se20/CFP thin films deposited under other conditions, achieving a low overpotential of 307 mV at a current density of 10mAcm-2 and low Tafel slope of 35mVdec-1. These results reveal that an appropriate substrate temperature during film formation improves the catalytic performance of thin film catalysts to some extent. A combination of lowcharge resistance and large electrochemically active surface area contributes to the electrocatalytic performance of the Fe40Co40Se20/CFP thin films. [ABSTRACT FROM AUTHOR]

In an attempt to explore high efficient and cheap electrocatalyst for water splitting hydrogen production, small molybdenum carbide nanoparticles with the size about 3–6 nm are loaded on three-dimensional N-doped carbon matrix successfully with ammonium heptamolybdate ((NH 4 ) 6 Mo 7 O 24 ·4H 2 O) and filter paper as precursor by pyrolysis. Due to its small size, large surface area and high conductivity, this electrocatalyst shows excellent activity in hydrogen evolution reaction (HER). In acid media, its overpotential to achieve a current density of 10 mA·cm −2 is as low as 167 mV, with Tafel slope is only 73 mV·dec −1 . The electrocatalyst also shows large exchange current density (j 0 ) with the value 0.15 mA·cm −2 . Furthermore, it shows excellent durability after 1000 cycles of long-term test, and the catalytic current remains stable over 10 h at fixed overpotential. This work elucidates a feasible strategy to obtain efficient electrocatalysts with cheap and naturally sustainable material as precursor and shed some light on the exploration and optimization of electrocatalysts in energy chemistry. The HER of this electrocatalyst is studied and the results illustrate it exhibits a stable hydrogen evolution rate of 44.5 μmol·h −1 with faradaic efficiency about 100%. [ABSTRACT FROM AUTHOR]

Various electrocatalysts are extensively examined for their ability to selectively produce desired products by electrochemical CO2 reduction reaction (CO2RR). However, an efficient CO2RR electrocatalyst doesn't ensure an effective co‐catalyst on the semiconductor surface for photoelectrochemical CO2RR. Herein, Bi2S3 nanorods are synthesized and electrochemically reduced to Bi nanoplates that adhere to the substrates for application in the electrochemical and photoelectrochemical CO2RR. Compared with commercial‐Bi, the Bi2S3‐derived Bi (S‐Bi) nanoplates on carbon paper exhibit superior electrocatalytic activity and selectivity for formate (HCOO−) in the electrochemical CO2RR, achieving a Faradaic efficiency exceeding 93%, with minimal H2 production over a wide potential range. This highly selective S‐Bi catalyst is being employed on the Si photocathode to investigate the behavior of electrocatalysts during photoelectrochemical CO2RR. The strong adhesion of the S‐Bi nanoplates to the Si nanowire substrate and their unique catalytic properties afford exceptional activity and selectivity for HCOO− under simulated solar irradiation. The selectivity observed in electrochemical CO2RR using the S‐Bi catalyst correlates with that seen in the photoelectrochemical CO2RR system. Combined pulsed potential methods and theoretical analyses reveal stabilization of the OCHO* intermediate on the S‐Bi catalyst under specific conditions, which is critical for developing efficient catalysts for CO2‐to‐HCOO− conversion. [ABSTRACT FROM AUTHOR]

Abstract Developing efficient bifunctional electrocatalysts and gaining fundamental understanding of reaction mechanisms are crucial for practical water splitting. Herein, a bifunctional NiSe 2 nanoparticles/carbon fiber paper (NSN/CFP) electrode is fabricated by the pyrolysis of Ni(NO 3) 2 on CFP, followed by a selenization step. The as-prepared electrocatalysts exhibit superior overall water splitting behavior in 1 M KOH with low overpotentials of 145 mV and 280 mV at current densities of 10 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) respectively, comparable to the performance of 20% Pt/C and RuO 2. Detailed compositional and morphological studies reveal that the NiSe 2 gradually transforms into an amorphous Ni(OH) 2 /NiOOH heterojunction during both HER and OER in alkaline medium. Based on these experimental results, an oxidation-induced self-reconstruction mechanism is proposed. Owing to the highly-oxidized Ni(OH) 2 /NiOOH active species, the self-reconstructed structure enhances the water splitting under fixed potentials for a prolonged time of 96 h with negligible current degradation. This work not only provides a facile route to fabricate efficient and stable electrocatalysts for large-scale water splitting but also reveals an underlying structural evolution mechanism, which guides the rational design of heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

Exploring noble-free electrocatalyst for hydrogen evolution by electrolysis of water is significant. Herein, porous Ni(OH) 2 @Ni spherical particles are electrodeposited on carbon papers as efficient electrocatalysts for hydrogen evolution reaction (HER) from water. Due to the porous and composite structure, the HER activity of Ni(OH) 2 @Ni/CP is better than the single phase Ni or Ni(OH) 2 particles on the carbon paper. The overpotential of Ni(OH) 2 @Ni/CP is 106 mV at the current density of 10 mA cm−2 and the Tafel slope is 88 mV dec−1. Moreover, the stability of the catalysts tested for 12 h is also good for HER. Furthermore, the small R ct (1.65 Ω) of Ni(OH) 2 @Ni/CP provides the evident for its excellent catalytic performance. The method of electrodeposition provides the controllable uniform size for porous spherical Ni(OH) 2 @Ni particles. Moreover, the Faradaic efficiency for hydrogen evolution is 100%. Image 1 • The overpotential of Ni(OH) 2 @Ni/CP is 106 mV (10 mA cm−2). • The Tafel slope is 88 mV dec−1 and the stability are good for 12 h. • One-pot preparation of Ni(OH) 2 @Ni/CP via through cyclic voltammetry (CV). [ABSTRACT FROM AUTHOR]

The layers were prepared by ion beam assisted deposition of iridium and platinum onto AVCarb® Carbon Fiber Paper P50 electrocatalyst supports for the production of diffusion layers of the membrane-electrode assemblies of low temperature fuel cells with polymer electrolyte membrane. Formation of the layers in the ion beam assisted deposition mode, by means of the deposition of metal and mixing of precipitating layer with the substrate by the accelerated (U=10 kV) ions of the same metal, was performed. In this process neutral fraction of metal vapour and ionized plasma of vacuum pulsed electric arc discharge were used. The investigations of morphology and composition of layers were carried out by the scanning electron microscopy, energy dispersive X-ray microanalysis, wave dispersive X-ray fluorescence analysis, and the Rutherford backscattering spectrometry methods. It was established that the obtained catalytic layers contain atoms of the deposited metals and substrate material as well as impurity oxygen atoms. The surfaces contain also metal inclusions of several micrometer size which arise from the precipitation of deposited metal droplets from the arc discharge of an ion source. The content of iridium and platinum atoms in the layers is ≈2×10¹ cm-2; the concentration of the deposited metals equals about several atomic percent. [ABSTRACT FROM AUTHOR]

The development of transition metal-based materials to replace precious metal electrocatalysts in a facile and efficient approach is of great importance for water splitting. The NiS/MoS 2 complex grown in situ on carbon paper (NiS/MoS 2 /CP) by a one-step hydrothermal method was successfully constructed as an efficient electrocatalyst. The synergetic effects of the superhydrophilic/aerophobic surface, hierarchical nanostructure and strong mechanical adhesion to a highly conductive substrate give the NiS/MoS 2 /CP complex outstanding catalytic activity and durability. Specifically, it exhibits relatively low overpotentials of 119 mV (at a current density of 10 mA cm−2) and 314 mV (at a current density of 100 mA cm−2) for the hydrogen evolution reaction and oxygen evolution reaction, respectively. In addition, the NiS/MoS 2 /CP complex can also be used as an electrolyzer that reaches a current density of 10 mA cm−2 at a cell voltage of 1.48 V without decay after 30 h of durability testing, making it an ideal electrocatalyst for water splitting towards practical application. [Display omitted] • The surface of carbon paper was transformed to be super-hydrophilic/aerophobic via calcination. • NiS/MoS 2 composite is grown in-situ on carbon paper by a facile one-step hydrothermal method. • The NiS/MoS 2 /CP complex exhibits high catalytic activity and excellent durability. [ABSTRACT FROM AUTHOR]

Transition-metal chalcogenides as the promising alternatives to noble-metal-based electrocatalysts for hydrogen evolution reaction (HER) with high activity and durability in water splitting have attracted extensive attention in recent years. Herein, Co z Ni y S x @PPy composites with three-dimensional (3D) cauliflower-like were firstly prepared on carbon fiber paper (CFP) via a simple and efficient electrochemical reduction of elemental sulfur in the precursor of S@PPy composite coated on CFP to react with Co and Ni ions in the electrolyte. The optimum electrode, i.e., Co z Ni y S x @PPy/CFP-6 (A-6) prepared by using an electrolyte with a Co/Ni molar ratio of 0/6, showed excellent catalytic activity (with an overpotential of 185 mV@10 mA cm−2 and a small Tafel slope of 78.13 mV dec−1) as well as long-term stability (at least 100 h) in 1 M KOH solutions. This work provides a novel way to fabricate effective and non-noble-metal electrodes for HER in water splitting. Image 1 • An electrochemical reduction of sulfur way is used to prepare the TMCs. • The relationship of nickle and cobalt in the volcano plot is proved by experiment. • The mixed crystals of Ni y S x strengthen catalytic activity and stability of HER. [ABSTRACT FROM AUTHOR]

Herein, we develop a facile and efficient Thermal-Vaporization-Transformation (TVT) approach to prepare a highly active BP directly grown on carbon paper as the electrode for Oxygen evolution reaction (OER), showing a low onset potential of 1.45 V versus RHE. Simultaneously, the current density of BP-CP illustrates the excellent electro-catalysis stability only decreases by 3.4% after continuous operation for 10,000 s. [Display omitted] • BP-CP for OER is successfully synthesized by a novel efficient TVT approach. • The raw materials of the reaction are only the red phosphorus and carbon. • BP-CP exhibits a low onset potential and excellent electro-catalysis stability. • Electrocatalytic performance is fully demonstrated by DFT calculation in details. Black phosphorus (BP), as a new 2D material, is normally synthesized by a high-pressure and high-temperature (HPHT) method from white and red phosphorus, which severely hinders the further development of BP for any potential applications and leads to search for other potential applications of BP with big challenge. Herein, we develop a facile and efficient Thermal-Vaporization-Transformation (TVT) approach to prepare a highly active BP directly grown on carbon paper as the electrode for Oxygen evolution reaction (OER), showing a low onset potential of 1.45 V versus RHE. Simultaneously, the current density of BP-CP illustrates the excellent electro-catalysis stability only decreases by 3.4% after continuous operation for 10000 s. Meanwhile, the density functional theory (DFT) calculations further illustrates the P-doped carbon layer in the upper side of BP layer is actually responsible for its enhanced OER property, and the adjacent carbon atoms of the embedded P atoms are actually the active sites due to the induced local change distribution by intramolecular change transfer. Considering the facile, but efficient and scalable, TVT approach can directly synthesize BP-CP with excellent OER performance, which is promising for BP electrocatalysts used for OER in metal-air batteries, fuel cells, water-splitting devices, even other key renewable energy. [ABSTRACT FROM AUTHOR]

Developing high-performance oxygen reduction electrocatalysts are crucial in fuel cells. Here, we report the novel nitrogen-doped carbon sheets as an effective electrocatalyst for oxygen reduction reaction (ORR) derived from napkin paper by thermal annealing in an NH3 atmosphere. The obtained typical sample (N-CS-1000) shows decent ORR activity in alkaline and acidic media due to the synergetic enhancement effect resulted from its nitrogen doping, high Brunauer-Emmett-Teller (BET) surface area (up to 1839 m² g-1), unique carbon sheets with many folds and nanoporous structure. This work provides a valuable inspiration for using resource-rich napkin paper as raw material to synthesize relevant functional carbon materials with other practical applications, such as lithium-ion battery, gas sensor and supercapacitor. [ABSTRACT FROM AUTHOR]

BACKGROUND: Fabrication of cost‐effective and durable materials for efficient hydrogen production in splitting water (hydrogen evolution reaction) is of importance for the successful utilization of hydrogen‐based green energy technologies. Therefore, electrocatalytic materials have been designed with a simple approach using electrodeposition of gold nanoparticles (AuNPs) and thin film (AuTF) directly on reduced graphene oxide (rGO) paper. As‐prepared paper electrocatalysts (AuNPs/rGO and AuTF/rGO) were characterized by X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). RESULTS: Free‐standing and flexible AuNPs/rGO and AuTF/rGO electrocatalysts have exhibited excellent performances on HER with low Tafel slopes (88 and 112 mV dec−1), low onset potentials (−47 and −55 mV), small overpotentials of only −176 and −204 mV to drive 10 mA cm−2, respectively, and high durability even with the rolled design. The outstanding performance of these two electrocatalysts can be attributed to the uniform distribution of 20‐nm‐sized AuNPs and the deposition of well‐ordered AuTF on rGO paper, providing an increment in the surface area and an enhancement of the electron density. CONCLUSION: The controllable design of AuNPs/rGO and AuTF/rGO electrocatalysts, together with their high flexibility, good stability and promising results, suggest potential use in future applications of H2 production in splitting water. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Integration of highly active electrocatalysts and three-dimensional (3D) conductive frameworks to create a stable and highly efficient air electrode with low overpotential under high discharge current density is a key approach to realize the commercialization of metal air batteries, which involve the oxygen reduction reaction (ORR) at the cathode end. We develop a self-reduction synthesis method for the fabrication of silver-carbon fiber paper (Ag-CFP) as an air electrode of aluminum air (Al-air) batteries. The obtained Ag-CFP is characterized as oxygen electrode by using Cyclic voltammograms (CVs), linear sweep voltammograms (LSVs) and Rotating Disk Electrode (RDE) voltammetrys techniques. The results demonstrated that the Ag-CFP exhibited promising ORR performance. Kouteckye-Levich analysis indicated that a two-electron reaction was favored for the ORR mechanism of the Ag-CFP electrode. A home-built Al-air cell was used to further determine the cathode performance under real operation condition. The resulting primary Al-air battery showed an impressive discharge peak power density of 108.1 mW cm-2, specific capacity of 2917 mA h g-1 and energy density of 4346 W h kg-1, outperforming that of commercial Ag powder air electrode. [ABSTRACT FROM AUTHOR]

Transition metal oxides (TMOs) have great potential application in oxygen evolution reaction (OER). However, the inferior electrical conductivity and limited active sites of TMOs lead to their sluggish electrocatalytic efficiency. Herein, we adopted a two-step solvothermal approach to fabricate hierarchical CoO@NiO porous core–shell nanoarrays on carbon paper (denoted as CoO@NiO/CP). We found that numerous NiO nanofibers were uniformly coated over the surface of CoO nanosheets, forming a well-defined integrated interfacial nanocomposite. When acting as a catalyst for the OER, CoO@NiO/CP showed enhanced electroactivity with lower overpotential (323 mV at 10 mA cm−2), outstripping both pure CoO nanosheet array and NiO nanofiber array. Furthermore, it displayed outstanding OER stability, and the potential attenuation was only 3.4% after a 24 h chronopotentiometry test. The remarkable OER properties of CoO@NiO/CP were mainly due to its unique heterointerface between CoO and NiO, which promoted electron/charge transfer, increased electrocatalytic reactive sites, and improved electrical conductivity. Our presented findings provide a rational and practical interface-engineering approach for fabricating an advanced OER electrocatalyst. [ABSTRACT FROM AUTHOR]

The electrocatalytic oxidation of glycerol by metal electrocatalysts is an effective method of low-energy-input hydrogen production in membrane reactors in alkaline conditions. The aim of the present study is to examine the proof of concept for the gamma-radiolysis-assisted direct growth of monometallic gold and bimetallic gold–silver nanostructured particles. We revised the gamma radiolysis procedure to generate free-standing Au and Au-Ag nano- and micro-structured particles onto a gas diffusion electrode by the immersion of the substrate in the reaction mixture. The metal particles were synthesized by radiolysis on a flat carbon paper in the presence of capping agents. We have integrated different methods (SEM, EDX, XPS, XRD, ICP-OES, CV, and EIS) to examine in detail the as-synthesized materials and interrogate their electrocatalytic efficiency for glycerol oxidation under baseline conditions to establish a structure–performance relationship. The developed strategy can be easily extended to the synthesis by radiolysis of other types of ready-to-use metal electrocatalysts as advanced electrode materials for heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

Metal organic framework (MOF)‐based materials have been widely studied and reported as efficient electrocatalysts for the hydrogen evolution reaction (HER), owing to their high surface areas, controllable structures, and tunable pore sizes. However, the intrinsically poor electrical conductivity of most MOFs hinders their directly applications as electrocatalysts. Herein, copper‐centered MOFs (HKUST‐1) have been electrodeposited directly onto the current collector. These electrochemically prepared HKUST‐1@carbon paper hybrids exhibited significantly enhanced electrocatalytic performances for the HER, including a positively shifted of onset potential, a lower overpotential, and a smaller Tafel slope, as compared to the conventional hydrothermally prepared HKUST‐1. The proposed electrodeposited synthesis strategy for MOF‐based electrocatalysts is fast, efficient, mild, and environmentally friendly. This work may also extend to other MOF materials and any conductive substrate, thus providing a facile strategy for the preparation of MOF‐based catalysts with high efficiency and low cost. [ABSTRACT FROM AUTHOR]

Carbon-based single-atom catalysts, a promising candidate in electrocatalysis, offer insights into electron-donating effects of metal center on adjacent atoms. Herein, we present a practical strategy to rationally design a model catalyst with a single zinc (Zn) atom coordinated with nitrogen and sulfur atoms in a multilevel carbon matrix. The Zn site exhibits an atomic interface configuration of ZnN4S1, where Zn's electron injection effect enables thermal-neutral hydrogen adsorption on neighboring atoms, pushing the activity boundaries of carbon electrocatalysts toward electrochemical hydrogen evolution to an unprecedented level. Experimental and theoretical analyses confirm the low-barrier Volmer-Tafel mechanism of proton reduction, while the multishell hollow structures facilitate the hydrogen evolution even at high current intensities. This work provides insights for understanding the actual active species during hydrogen evolution reaction and paves the way for designing high-performance electrocatalysts. [ABSTRACT FROM AUTHOR]

Abstract: Platinum–ruthenium (Pt–Ru) nanoparticles were successfully deposited, for the first time, on the surface of SnO2 nanowires grown directly on carbon paper (Pt–Ru/SnO2 NWs/carbon paper) by potentiostatic electrodeposition method. The resultant Pt–Ru/SnO2 NWs/carbon paper composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrocatalytic activities of these composite electrodes for methanol oxidation were investigated and higher mass and specific activities in methanol oxidation were exhibited as compared to Pt–Ru catalysts deposited on glassy carbon electrode. [Copyright &y& Elsevier]

Molybdenum disulfide (MoS2) or tungsten disulfide (WS2), as a promising catalyst, is widely investigated for hydrogen evolution reaction (HER). In this work, a composite electrocatalysts MoxW1-xS2 is successfully decorated on carbon fiber paper (CFP) through a facile hydrothermal method. The three-dimensional porous CFP can enable the diffusion and penetration of electrolyte. Comparing with MoS2 and WS2 catalyst, the composite electrocatalyst MoxW1-xS2 nanosheets can expose the large number of electrochemically active sites. Hence, the as-prepared MoxW1-xS2/CFP (3:1) exhibit the outstanding HER catalytic activity with the small Tafel slope of 68 mV dec−1 and the low overpotential of − 178.4 ± 0.5 mV at a current density of 10 mA cm−2. Chronoamperometric current test for 18 h confirm the long-term stability of the composite electrocatalyst. [ABSTRACT FROM AUTHOR]

• Nanoarray-structured nitrogen-doped carbon paper was achieved via plasma treatment. • Amorphous NiFe-P nanoparticles were assembled on NCP by electrodeposition method. • The unique features endow NiFe-P/NCP electrode with superior catalytic performance. • The NiFe-P/NCP||NiFe-P/NCP couple shows a low voltage of 1.547 V at 10 mA cm–2. The exploration of high-performance and low-cost electrocatalysts for catalyzing both hydrogen and oxygen evolution reaction (HER and OER) at high current density is of vital significance for the commercialization of water splitting. Herein, amorphous NiFe phosphides are electrodeposited on 3D nanoarray-structured nitrogen-doped carbon paper (NCP) for direct use as a hybrid electrode toward overall water splitting. The as-prepared NiFe-P/NCP electrode requires only an overpotential of 0.226 and 0.125 V at 50 mA cm–2 for OER and HER, respectively. In addition, NiFe-P/NCP electrodes are further measured as a catalytic cathode and anode couple (NiFe-P/NCP||NiFe-P/NCP) for overall water splitting, exhibiting a low cell voltage of 1.547 to reach 10 mA cm–2 as well as a long-term durability. Our work reveals the significance of introducing well-designed substrate and bimetallic active species for enhanced electrochemical performance towards overall water splitting. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Highly efficient and durable anode electrocatalysts are the key to boost the performance of direct organic-molecule fuel cells (DOMFCs), yet there are still many challenges need to be solved. The PdPt alloy nanocrystals have been regarded as the most promising anode catalysts of DOMFCs, and the further improvement of their catalytic performance has attracted much attention. The effective routes includes tailoring the surface structure and optimizing the alloy composition of PdPt nanocatalysts. The high-index faceted structures possess high density of terraces and atomic steps which are efficient for electrooxidation reactions of small organic-molecule fuels, such as formic acid and ethanol. In particular, electrochemically-controlled synthesis methods present unique advantages in achieving such high-index faceted nanostructures. The current paper reports a direct electrodeposition of PdPt concave nanocubes on carbon paper (denoted as PdPt-CNC/CP). The prepared PdPt-CNC/CP has high-index faceted surface structures varying from {610} to {830}. When served as electrocatalysts, the PdPt-CNC/CP brings in outstanding mass specific activity and durability towards both formic acid oxidation reaction (FAOR) and ethanol oxidation reaction (EOR). More importantly, the selectivity of complete oxidation pathway through the cleavage of C-C bond on PdPt-CNC/CP during EOR in alkaline solution has been confirmed through NMR analysis. Based on the convenient method of direct electrodeposition of PdPt concave nanocubes on carbon paper and their excellent catalytic activity and durability, the PdPt-CNC/CP catalysts have potential advantages in being used as catalyst layers directly for membrane electrode assembly (MEA) in fuel cells, due to the reduced catalyst loading and simplified assembly process in comparison with traditional preparation procedure. Image 1 [ABSTRACT FROM AUTHOR]

Titanium dioxide is cheap, non-toxic, exhibits a high mechanical resistance, very stable in acidic and oxidative environments is being studied as alternative to carbon as catalyst support in low-temperature fuel cells. Herein, via pulsed laser deposition, various morphologies of TiO 2 thin films are synthesized at room temperature onto conductive microfibrous carbon paper substrate, which is the type of substrate, employed in energy storage and conversion devices. TiO 2 films deposited under vacuum and in the presence of mild pressure of oxygen are very smooth and dense. Instead, TiO 2 films deposited in the presence of helium atmosphere are of porous structures and vertically aligned. An increase in the helium pressure leads to the formation of forest-like vertically aligned nanostructures. Micro-Raman spectroscopy reveals that the films are amorphous and of rutile phase. X-ray photoelectron spectroscopy shows that Ti is in fully oxidized state of Ti 4+ . The electrocatalytic supporting properties to Pt are investigated in H 2 SO 4 and O 2 -saturated H 2 SO 4 solution. It is found that regardless of the film morphology, all the synthesized TiO 2 films dramatically increase the electroactive surface area of Pt and enhance its electroactivity towards oxygen reduction reaction as compared with bare Pt electrode. [ABSTRACT FROM AUTHOR]

An efficient water splitting electrocatalyst is presented. Cheap and sustainable cellulose filter paper, infiltrated with nickel acetate as the nickel source, and phenanthroline as a ligand and nitrogen source are carbonized together. Nitrogen functionalities turn out to be crucial coordination sites for the supported Ni/NiO(OH) particles. This simple and scalable one step procedure leads to powders, but also to complete membranes made of ≈10 wt% Ni, supported on nitrogen functionalized carbon. The non-noble catalyst shows a low onset potential (330 mV vs reversible hydrogen electrode), high current density (e.g., j > 25 mA cm−­2 at η = 430 mV), excellent kinetics (Tafel slope of 44 mV dec−1), and a very favorable stability (<5% decay after 10 h electrolysis) in the oxygen evolution. The performance is similar or even better compared to state-of-the-art noble metal catalysts (e.g., IrO2, Ir/C, Ru/C, and Pt/C). Because of the simple, cheap, and scalable preparation procedure the catalyst is highly promising for practical low price/tech applications. Interestingly, the system is also active in the hydrogen evolution reaction, leading to a promising bifunctional catalyst. The benchmark characteristics are η10 = 390 mV for oxygen evolution and η10 = 190 mV for hydrogen evolution, that is, an overall efficiency of 68% at 10 mA current density. [ABSTRACT FROM AUTHOR]

Electrooxidation of urea plays a substantial role in the elimination of urea-containing wastewater and industrial urea. Here, we report the electrodeposition of nickel hydroxide catalyst on commercial carbon paper (CP) electrodes from dimethyl sulphoxide solvent (Ni(OH)2-DMSO/CP) for urea electrooxidation under alkaline conditions. The physicochemical features of Ni(OH)2-DMSO/CP catalysts using scanning electron microscopy and X-ray photoelectron spectroscopy revealed that the Ni(OH)2-DMSO/CP catalyst shows nanoparticle features, with loading of <1 wt%. The cyclic voltammetry and electrochemical impedance spectroscopy revealed that the Ni(OH)2-DMSO/CP electrode has a urea oxidation onset potential of 0.33 V vs. Ag/AgCl and superior electrocatalytic performance, which is a more than 2-fold higher activity in comparison with the counterpart Ni(OH)2 catalyst prepared from the aqueous electrolyte. As expected, the enhancement in electrocatalytic activity towards urea was associated with the superficial enrichment in the electrochemically active surface area of the Ni(OH)2-DMSO/CP electrodes. The results might be a promising way to activate commercial carbon paper with efficient transition metal electrocatalysts, for urea electrooxidation uses in sustainable energy systems, and for relieving water contamination. [ABSTRACT FROM AUTHOR]

Spherical mesoporous carbon (SMC) was prepared by water in oil emulsification combined with sol-gel polymerization and activated with carbon dioxide. The SMCs had an average particle size of 44 μm, a specific surface area of 479 m2 g−1 and with a large mesopore volume of 1.12 cm3 g−1. The slit-shaped mesopores were embedded into the wall surface of the SMCs. As electrocatalysts, the electrochemical properties of SMCs toward the anthraquinone-2-sulfonic acid (AQS) and 1,2-benzoqinone-3,5-disulfonic acid (BQDS) redox couples were examined. The SMCs facilitated the fast reversible-electrochemical reaction with the kinetic rate constant of 9.73 × 10−4 cm s−1 for BQDS, and of 4.39 × 10−3 cm s−1 for AQS. Subsequently, the electrodes of an aqueous organic flow battery were fabricated onto carbon paper and carbon cloth using SMCs as the electrocatalysts. The flow battery performance was improved by around 1.7-fold, when the SMCs had a mass loading of 2 mg cm−2 with 20 wt% Nafion, fabricated onto carbon cloth. However, there was no significant performance improvement when the SMCs were fabricated onto carbon paper. Moreover, SMCs provided the most outstanding power density over other carbon electrocatalysts (i.e., graphene, Vulcan XC-72 and Vulcan XC-72R), from 2 to 3 fold, according to the superior physical and electrochemical properties. • SMCs prepared via sol-gel polymerization with water-oil emulsification system. • SMCs had superior electrochemical properties over carbon glass up to 100 times. • SMCs greatly improved an aqueous organic flow battery performance. • Power density from SMCs was about 2–3 time better over other carbon electrocatalysts. [ABSTRACT FROM AUTHOR]

• Shrub-like pt-rh catalysts with different metallic ratios on carbon paper were prepared by laser ablation. • The catalysts displayed higher tolerance to CO and higher catalytic activity towards ethanol oxidation. • Pt-Rh catalysts demonstrated long-term poisoning rates eight times lower than pt. Plasmas techniques are novel routes for the preparation of complex nanostructured materials for catalysis and clean hydrogen energy such as fuel cells. CBPLD technique allows enhanced interaction between the catalyst and the support and improved catalytic properties. Herein, a highly active and durable vertically aligned nanostructured shrub-like bimetallic Pt x Rh 100-x alloys with atomic ratios close to nominal values are grown on carbon paper substrate. The tolerance to CO poisoning and ethanol electrooxidation reactions are studied over these new types of shrub-like bimetallic Pt x Rh 100-x /CP catalysts, demonstrating that such structures effectively facilitate both processes and very low long-term poisoning rates. Such high catalytic activity accounts for two mechanisms: Rh a highly oxophilic transition metal activates water dissociation at lower potentials than Pt (bifunctional mechanism), and the ligand effect where Rh alters the electronic structure of the neighboring Pt suggesting a faster supply in OH ads. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Designing highly efficient electrocatalysts for oxygen evolution reaction is important to meet the requirement of various renewable energy storage and conversion devices. Generally, the performance of OER catalysts can be significantly improved by synergistic action of the underlying conductive substrate. In this work, a commercial graphite paper was used as a facile substrate with catalytic activity. Graphite paper produced 10 mA cm −2 at an overpotential of 447 mV with a Tafel slope of 62 mV dec −1 . By depositing NiFe hydroxide or Mn oxide film onto the graphite paper, the electrode presented a superior activity for water oxidation, which was believed to be synergistically contributed by their available electrochemically active sites associated with the deposited film and the active substrate. High activities were also accompanied by remarkable durability at large current density levels. Our results illustrated a guideline to the design of inexpensive and highly active composite electrode for water oxidation. [ABSTRACT FROM AUTHOR]

The rational design and preparation of earth-abundant, stable and efficient electrocatalysts for hydrogen production is currently the subject in extensive scientific and technological researches toward the future of a clean-energy society. Herein, a mace-like MoS 2 /NiCo 2 S 4 hierarchical structure is designed and synthesized on carbon fiber paper via a facile hydrothermal method, and evaluated as electrocatalyst for hydrogen evolution reaction. In the MoS 2 /NiCo 2 S 4 /carbon fiber paper hierarchical structures, MoS 2 nanosheets are dispersively distributed on the surface of NiCo 2 S 4 nanowires, which provides an enlarged surface area, abundant interfaces and catalytic active sites. As for hydrogen evolution reaction, such MoS 2 /NiCo 2 S 4 /carbon fiber paper heterostructures give rise to a hydrogen evolution reaction catalytic current density of 10 mA cm −2 with a lower overpotential of 139 mV and a smaller Tafel slope of 37 mV·dec −1 than those of MoS 2 /carbon fiber paper and NiCo 2 S 4 /carbon fiber paper counterparts, exhibiting a prominent electrocatalytic performance. Moreover, the electrocatalytic properties change little after 5000 CV cycles and continual electrolysis for 12 h without obvious decay, respectively, demonstrating high durability and stability. The excellent hydrogen evolution reaction performances endow the hierarchical configuration MoS 2 /NiCo 2 S 4 /carbon fiber paper with promising alternative in HER and other related renewable energy fields. [ABSTRACT FROM AUTHOR]

A layered binary Mn-Fe oxide as bi-functional electro-catalyst with nanopetals morphology is grown on porous carbon paper for the first time via one-step electrodeposition process. The electrocatalyst is characterized by X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive spectroscopy analysis. SEM analysis demonstrates notable morphology viz. nanopetals of the Mn-Fe oxide grown on carbon paper. The electrocatalytic activity is checked for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline medium. Rotating disk electrode (RDE) voltammetry is carried out to study the ORR kinetics, which proves that ORR process follows four-electron pathway in alkaline medium. Oxygen evolution reaction study reveals that it has higher activity for OER with a lower onset potential of 1.6 V vs RHE and higher current density of 11.5 mA/cm 2 at 2.0 V vs RHE reference electrode. [ABSTRACT FROM AUTHOR]

Hydrazine is often regarded as one of the most appealing fuels for fuel cells due to its high energy content, and also because it gives off only environmentally benign byproducts when it is used in fuel cells ( cf. many other fuels produce the greenhouse gas CO 2 ). However, current electrocatalysts for the hydrazine oxidation reaction (HOR) in direct hydrazine fuel cells involve the expensive, unsustainable noble metals such as Pt. Herein, using cellulose filter paper both as a precursor and a self-template, we show the synthesis of nanoporous carbon electrocatalysts that can efficiently electrocatalyze HOR. To make the electrocatalysts, first cellulose filter paper is modified with metal-amine complexes and then with silica shells. After carbonization of the resulting composite material at different temperatures, followed by removal of the silica shells, nanoporous carbon-based electrocatalysts are obtained. Notably, the intertwined structure of the cellulose matrix in the filter paper is taken advantage of to serve as a self-template, allowing the formation of the desired fibrous, nanoporous carbon electrocatalysts. The materials show a good electrocatalytic activity toward HOR, giving a low overpotential and a high current density. Thus, such nanoporous carbons can be good candidate materials to replace conventional metal-based catalysts commonly used in HOR and other related reactions. [ABSTRACT FROM AUTHOR]

The oxygen electrodes in unitized regenerative fuel cells (URFC) must have high activities towards oxygen reduction reaction (ORR) as well as oxygen evolution reaction (OER), thus requiring high loading of noble metal electrocatalysts. In this study, porous Pt/IrO 2 /carbon paper (CP) electrocatalysts were developed to reduce the metal loading. The Pt/IrO 2 /CP electrodes were fabricated by sequential formation of IrO 2 layers (loading 0.1 mg cm − 2 ) and porous Pt layers (0–0.3 mg cm − 2 ) on CP substrates by electrodeposition and spraying techniques, respectively. The fuel cell (FC) performances increased linearly up to 0.69 A cm − 2 with increasing Pt loading (up to ~ 0.3 mg cm − 2 ) at 0.6 V, whereas the water electrolysis (WE) activity was highest at Pt loading of 0.2 mg cm − 2 . The current densities in the FC and WE modes and round-trip efficiency of the developed Pt/IrO 2 /CP electrodes with the oxygen electrocatalysts loadings of 0.3 and 0.4 mg cm − 2 were higher or comparable to previously reported values with higher loading (1.5–4.0 mg cm − 2 ). These high performances with low loading are probably due to the facile oxygen and water transport through well-developed macropores originating from the open CP structures, providing effective utilization of the IrO 2 and Pt electrocatalysts towards OER and ORR, respectively. [ABSTRACT FROM AUTHOR]

It is a great challenge to synthesize efficient electrocatalysts for overall water splitting, especially non‐noble metal catalysts. Herein, one‐dimensional polycrystalline nanoneedles composed of CoO−Co9S8 nano heterostructures, in situ grown on carbon fiber paper are prepared for efficient overall water electrolysis. Due to strong electronic coupling, charge densities of Co2+/Co3+ in Co9S8 and Co2+ in CoO are favorably modified at the interface of CoO and Co9S8, resulting in optimized reaction intermediates absorption and greatly enhanced bifunctional HER/OER activities. CoO−Co9S8/CFP delivers a current density of 10 mA cm−2 in alkaline electrolyte at overpotentials of 184 mV and 270 mV for HER and OER, respectively. When used as electrocatalyst for overall water splitting, it needs a low cell potential of 1.66 V to realize water electrolysis at 10 mA cm−2. This work provides a new strategy to tune the electronic structures of transitional metal active sites via constructing nano heterostructures for efficient water electrolysis. [ABSTRACT FROM AUTHOR]

Dealloyed ternary Cu@Pt-Ru core-shell electrocatalysts supported on carbon paper (CP) are fabricated by cyclic-co-electrodeposition and selective copper dealloying (CCED-SCuD). The physical properties of this catalyst such as surface and bulk compositions, electronic structure modification, phase structure, crystallite size, compressive lattice strain, and morphology were characterized by X-ray photoemission (XPS), inductive-coupling plasma atomic spectroscopy (ICP-AES), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), scanning electron microscope, and transmission electron microscope (TEM). The best catalyst is Cu@Pt-Ru/CP, having core-shell structure with a Cu rich core and a Pt-Ru rich shell with grain size around 100 nm. Cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) reveal that ternary Cu@Pt-Ru/CP gives significantly low onset potential and high activity towards methanol electrooxidation reaction (MOR), achieving specific peak current at 265 mA.mg Pt −1 , which is significantly higher than that of dealloyed binary Cu@Pt/CP (211 mA.mg Pt −1 ) and pure Pt/CP (170 mA.mg Pt −1 ). The highest current stability is found for the ternary Cu@Pt-Ru/CP with decay rate at 2.3 × 10 −3 mA.mg Pt −1 .s −1 . The enhancements of both activity and stability of the Cu@Pt-Ru/CP from the higher electrochemical surface area (ECSA) are major reason, which originates from the higher exposed surface of Pt, while the higher compressive lattice strain, electronic structure modification, and bi-functional mechanism are minor reason. However, the lower current density (J P ) of the ternary Cu@Pt-Ru/CP suggests lower intrinsic reactivity. [ABSTRACT FROM AUTHOR]

Multi-wall carbon nanotubes (MWCNTs) have been synthesized on a carbon fiber paper (CFP) via a simple surface reaction of hydrocarbon decomposition using nickel nanoparticles as catalysts at 1023 K. Pd nanoparticles supported on MWCNTs/CFP are used as electrocatalysts for ethanol electrooxidation in alkaline media. The results shows that the Pd/MWCNTs/CFP electrocatalyst gives higher reaction activity and more stable performance than the commercial Pd/C and Pd/CFP electrocatalyst for ethanol oxidation in alkaline medium. [ABSTRACT FROM AUTHOR]

Among numerous noble-metal-free electrocatalysts, molybdenum sulfides are recognized as promising candidates for hydrogen evolution reaction (HER). Owing to abundant under-coordinated sulfur atoms serving as catalytically active centers, intensive spectra studies have revealed that the HER property of amorphous molybdenum sulfide ( a -MoS x ) is superior to crystal molybdenum sulfide ( c -MoS 2 ). In this work, nitrogen-doped active carbon (NAC) is obtained through plasma treatment and amorphous MoS x /NAC hybrid catalyst films are electrodeposited on carbon fiber papers (CFP) which are employed as porous three-dimensional electrodes with low resistivity. The incorporation of NAC increases the electrochemically active surface area, enhances the electron transport, and facilitates the reaction kinetics. Moreover, the functionality durability benefits from synergistic effect between a -MoS x and NAC. Thus, the obtained hybrid catalyst delivers the excellent HER activity, requiring only 203 mV overpotential to achieve a geometrical current density of 100 mA cm −2 with a Tafel slope of ∼43.9 mV per decade. [ABSTRACT FROM AUTHOR]

Designing cost-effective, highly efficient and stable electrocatalysts for oxygen evolution reaction is of paramount importance. Although extensive studies have focused on the relatively cheaper 3d transition metal oxide catalysts, the effect of trimetallic composites on the catalytic ability still remains elusive. Herein, we selected FeCo catalyst as the platform and investigated the catalytic activity of trimetallic composites, which were synthesized by incorporating Mo, W or Ni into the FeCo catalyst. The experimental results evidenced that FeCoMo/CP exhibited high catalytic activity towards water oxidation in alkaline solution, which required an overpotential of only ∼270 mV. Such impressive catalytic performance of FeCoMo/CP can be attributed to the fact that the introduction of Mo appreciably modulated the electronic structure of the Fe and Co centers, leading to an enhancement in intrinsic active sites. Benefiting from the tight contact with the highly conductive carbon paper substrate, FeCoMo/CP showed excellent stability up to 120 h. These results indicate that the surface engineering of FeCo-based catalysts by incorporating non-noble metals is a rational strategy to promote the performance of electrocatalysts. [ABSTRACT FROM AUTHOR]

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Large-scale growth of low-cost, efficient, and durable non-noble metal-based electrocatalysts for water splitting is crucial for future renewable energy systems. Atomic layer deposition (ALD) provides a promising route for depositing uniform thin coatings of electrocatalysts, which are useful in many technologies, including the splitting of water. In this communication, we report the growth of a NiO/Ni catalyst directly on carbon fiber paper by atomic layer deposition and report subsequent reduction and oxidation annealing treatments. The 10-20 nm NiO/Ni nanoparticle catalysts can reach a current density of 10 mA·cm-2 at an overpotential of 189 mV for hydrogen evolution reactions and 257 mV for oxygen evolution reactions with high stability. We further successfully achieved a water splitting current density of 10 mA·cm-2 at 1.78 V using a typical NiO/Ni coated carbon fiber paper two-electrode setup. The results suggest that nanoparticulate NiO/Ni is an active, stable, and noble-metal-free electrocatalyst, which facilitates a method for future water splitting applications. [ABSTRACT FROM AUTHOR]

Along with reduced graphene oxide (RGO), water soluble Prussian blue nanoparticles (PBNPs, around 6 nm) are synthesized and broadly characterized. These two types of highly stable, low-cost and chemically compatible nanomaterials are exploited as building ingredients to prepare electrically enhanced and functionally endorsed nanohybrid electrocatalysts, which are further transformed into free-standing graphene papers. PBNPs doped graphene papers show highly efficient electrocatalysis towards reduction of hydrogen peroxide and can be used alone as flexible chemical sensors for potential applications in detection of hydrogen peroxide or/and other organic peroxides. The as-prepared PBNPs-RGO papers are further capable of biocompatible accommodation of enzymes for development of free-standing enzyme based biosensors. In this regard, glucose oxidase is used as an example for electrocatalytic oxidation and detection of glucose. The present work demonstrates a facile and highly reproducible way to construct free-standing and flexible graphene paper doped with electroactive catalyst. Thanks to high stability, low-cost and efficient electrocatalytic characteristics, this kind of nanohybrid material has potential to be produced on a large scale, and offers a broad range of possible applications, particularly in the fabrication of flexible sensing devices and as a platform for electrocatalytic energy conversion. [ABSTRACT FROM AUTHOR]

Amorphous Ru-Pi nanoclusters deposited on PEDOT modified carbon fibre paper electrode have been investigated as a potential oxygen evolution electrocatalyst. CFP/PEDOT/Ru-Pi electrode was prepared by electrodeposition of Ru-Pi nanoclusters on PEDOT decorated CFP using cyclic voltammetry (CV). Field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FESEM-EDS), attenuated total reflection with Fourier-transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD) were used for physicochemical characterization. Linear sweep voltammetric (LSV) studies corroborated that CFP/PEDOT/Ru-Pi has exhibited higher oxidation peak current when compared to other modified electrodes. CFP/PEDOT/Ru-Pi electrode has displayed better catalytic activity towards oxygen evolution reaction at low onset and over potential. The modified electrode has also offered better stability towards the oxidation reaction in phosphate buffer solution (PBS) and the working stability of these electrodes were determined using LSV and CV. • An efficient CFP/PEDOT/Ru-Pi electrocatalyst is developed for oxygen evolution reaction. • CFP/PEDOT/Ru-Pi has governed substantial increase in current at Linear sweep voltammetry in PBS solution. • The over potential of CFP/PEDOT/Ru-Pi is lies in the range of 340 mV (300–400) mV indicating excellent OER electrocatalyst. • CFP/PEDOT/Ru-Pi electrocatalyst offered proficient activity. [ABSTRACT FROM AUTHOR]

Transition metal@nitrogen–carbon (M@NC) catalysts are greatly desired for zinc–air batteries due to the promising oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) properties. Herein, a uniformly distributed Co@NC catalyst derived from metal–organic frameworks is developed. The CoNx species and Co nanoparticles encapsulated in carbon networks promote ORR and OER kinetics synergistically. Moreover, a novel structure is designed for exposing active sites, which consists of 3D macroporous skeleton embedded in carbon fiber paper. It is revealed that the outstanding ORR and OER properties attribute to the sufficient active area obtained from porous structure and ultra‐thickness (280 µm). Besides, interconnected macropores provide abundant channels for mass transport. The liquid ZABs assembled using 3DOMCo@NC‐1‐090 displays outstanding performances. [ABSTRACT FROM AUTHOR]