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Electrooxidation of biomass‐derived glycerol which is regarded as a main byproduct of industrial biodiesel production, is an innovative strategy to produce value‐added chemicals, but currently showcases slow kinetics, limited Faraday efficiency, and unclear catalytic mechanism. Herein, we report high‐efficiency electrooxidation of glycerol into formate via a Cu doped NiCo alloy catalyst supported on nickel foam (Cu−NiCo/NF) in a coupled system paired with nitrate reduction. The designed Cu−NiCo/NF delivers only 1.23 V vs. RHE at 10 mA cm−2, and a record Faraday efficiency of formate of 93.8 %. The superior performance is ascribed to the rapid generation of NiIII−OOH and CoIII−OOH species and favorable coupling of surface *O with reactive intermediates. Using Cu−NiCo/NF as a bifunctional catalyst, the coupled system synchronously produces NH3 and formate, showing 290 mV lower than the coupling of hydrogen evolution reaction, together with excellent long‐term stability for up to 144 h. This work lays out new guidelines and reliable strategies from catalyst design to system coupling for biomass‐derived electrochemical refinery. [ABSTRACT FROM AUTHOR]

Metal alloys have garnered significant attention as electrocatalysts for the alkaline hydrogen evolution reaction due to their exceptional conductivity and durability. Herein, FeCo alloy nanoparticles are prepared on a carbon cloth skeleton by a low-temperature thermal technique with FeCo Prussian blue analog as the precursor. The strong electronic interactions between Co and Fe facilitate electron transferring from Fe to Co and play a crucial role in modulating hydrogen adsorption and accelerating charge transfer. The alloy exhibits outstanding catalytic activity, such as a small overpotential of 161 mV for a current density of 10 mA cm−2 in the 1.0 M KOH electrolyte as well as a Tafel slope of 104 mV dec−1. The catalyst can be operated continuously for 100 h at a current density of 100 mA cm−2 with minimal changes in the potential, morphology, and composition. The exceptional activity, stability, and synergistic effects provide valuable guidance to the design and fabrication of efficient and sustainable electrocatalysts for renewable energy applications. [Display omitted] • FeCo alloy nanoparticles are prepared on carbon cloth by low-temperature technique. • Strong electronic interactions between Co and Fe facilitate electron transfer. • Electron transfer from Fe to Co to modulate hydrogen adsorption behavior. • The FeCo needs an overpotential of 161 mV for a current density of 10 mA cm−2 • The catalyst shows no morphology or composition changes at 100 mA cm−2 for 100 h. [ABSTRACT FROM AUTHOR]

Attributed to the enriched adsorption of urea, tailored adsorption of OH−, and high exposure of active sites, the defect-rich PMo-NiCo exhibits satisfied catalytic performance for UOR (η 10/2000 = 1.27/1.51 V) and HER (η −10/−500 = −57/256 mV). [Display omitted] • NiCo compressive strain inhibits OH− adsorption, while enriching the urea adsorption. • OH− is preferentially adsorbed on oxygenophilic P/Mo, releasing the Ni/Co active site. • PMo-NiCo catalyst could avoid the competition of OER and realize highly efficient UOR. Alloys with bimetallic electron modulation effect are promising catalysts for the electrooxidation of urea. However, the side reaction oxygen evolution reaction (OER) originating from the competitive adsorption of OH− and urea severely limited the urea oxidation reaction (UOR) activity on the alloy catalysts. This work successfully constructs the defect-rich NiCo alloy with lattice strain (PMo-NiCo/NF) by rapid pyrolysis and co-doping. By taking advantage of the compressive strain, the d-band center of NiCo is shifted downward, inhibiting OH− from adsorbing on the NiCo site and avoiding the detrimental OER. Meanwhile, the oxygenophilic P/Mo tailored specific adsorption sites to adsorb OH− preferentially, which further released the NiCo sites to ensure the enriched adsorption of urea, thus improving the UOR efficiency. As a result, PMo-NiCo/NF only requires 1.27 V and −57 mV to drive a current density of ±10 mA cm−2 for UOR and hydrogen evolution reaction (HER), respectively. With the guidance of this work, reactant competing adsorption sites could be tailored for effective electrocatalytic performance. [ABSTRACT FROM AUTHOR]

Emerging global carbon monoxide (CO) emissions directly affect global warming and modify atmospheric chemistry. The entreaty for benchmark heterogeneous oxidation of CO into CO2 is a substantial and efficient strategy to reduce CO. Heterogeneous oxidation is popular because it accelerates chemical reactions. In this work, the rational framework for synthesizing a nanocatalyst Pt–CeO2 by hydrothermal leaching of AlCe-Ptx intermetallic compound and subjecting it to heat treatments in a H2/N2 atmosphere. After hydrothermal leaching, the contact between the active sites and the Pt–CeO2 nanocatalyst contributes to enhanced catalytic performance on CO conversion. Further, various spectroscopic and microscopic methods analyzed the prepared material's structural and microstructure characteristics. The inclusion of noble Pt metal alters the surface properties of the nanocatalyst. The enhanced catalytic activity due to their higher thermal stability, chemical strength, metal–support interaction, and well-defined structures have a noticeable effect on the catalytic process. These factors caused high surface area and less crystallite size, achieving 100% CO conversion at low temperatures. Hence, the obtained outcomes bear substantial practical relevance to the developing perspectives of energy-storage applications. [ABSTRACT FROM AUTHOR]

Developing electrocatalysts that exhibit both high activity and ammonia selectivity for nitrate reduction is a significant and demanding challenge, primarily due to the complex nature of the multiple-electron reduction process involved. An encouraging approach involves coupling highly active precious metals with transition metals to enhance catalytic performance through synergy. Here, we report a ruthenium-nickel alloy catalyst with nanosheets (Ru-Ni NSs) structure that achieves a remarkable ammonia Faradaic efficiency of approximately 95.93%, alongside a yield rate of up to 6.11 g·h−1·cm−2. Moreover, the prepared Ru-Ni NSs exhibit exceptional stability during continuous nitrate reduction in a flow reactor for 100 h, maintaining a Faradaic efficiency of approximately 90% and an ammonia yield of 37.4 mg·L−1·h−1 using 0.05 M nitrate alkaline electrolyte. Mechanistic studies reveal that the catalytic process follows a two-step pathway, in which HONO serves as a migration intermediate. The presence of a partially oxidized Ru (002) surface enhances the adsorption of nitrate and facilitates the release of the migration intermediate by adjusting the strength of the electrostatic and covalent interactions between the adsorbate and the surface, respectively. On the other hand, the Ni (111) surface promotes the utilization of the migration intermediate and requires less energy for NH3 desorption. This tandem process contributes to a high catalytic activity of Ru-Ni NSs towards nitrate reduction. [ABSTRACT FROM AUTHOR]

The fine regulation of catalysts by the atomic-level removal of inactive atoms can promote the active site exposure for performance enhancement, whereas suffering from the difficulty in controllably removing atoms using current micro/nano-scale material fabrication technologies. Here, we developed a surface atom knockout method to promote the active site exposure in an alloy catalyst. Taking Cu3Pd alloy as an example, it refers to assemble a battery using Cu3Pd and Zn as cathode and anode, the charge process of which proceeds at about 1.1 V, equal to the theoretical potential difference between Cu2+/Cu and Zn2+/Zn, suggesting the electricity-driven dissolution of Cu atoms. The precise knockout of Cu atoms is confirmed by the linear relationship between the amount of the removed Cu atoms and the battery cumulative specific capacity, which is attributed to the inherent atom-electron-capacity correspondence. We observed the surface atom knockout process at different stages and studied the evolution of the chemical environment. The alloy catalyst achieves a higher current density for oxygen reduction reaction compared to the original alloy and Pt/C. This work provides an atomic fabrication method for material synthesis and regulation toward the wide applications in catalysis, energy, and others. [ABSTRACT FROM AUTHOR]

To improve the DRM reaction performance of the catalysts, a series of Co–Ni/WC-AC catalysts are prepared by impregnation using WC-AC as the support. The structural features of the fresh and spent catalysts are characterized by BET, XRD, H 2 -TPR, XPS and TG. The results show that the introduction of Ni in the 20Co/WC-AC catalyst promotes the conversion of W species to WC. Further, WC enhances the interaction between the active metal and the support. Thus, the activity and sintering resistance of Co–Ni/WC-AC catalysts are improved. It is also found that the introduction of different ratios of Ni has a significant effect on the chemical environment (oxygen environment) on the catalyst surface.10Co–10Ni/WC-AC catalysts showed high surface O α and O β contents of 26% and 53%, respectively. The catalyst shows excellent catalytic performance. The conversion of CH 4 and CO 2 is stable at about 84% and 85% at 800 °C. • Co–Ni catalysts were prepared by impregnation using WC-AC as the support. • The Ni introduced in the catalyst promoted the conversion of W species to WC. • Different Co/Ni ratios have a significant effect on the oxygen environment. • The interaction of Co–Ni bimetals with support improves the catalytic performance. • 10Co–10Ni/WC-AC catalysts showed excellent catalytic performance. [ABSTRACT FROM AUTHOR]

Alloy catalyst has been widely studied and used for hydrolytic dehydrogenation of ammonia borane (NH 3 BH 3 , AB) with excellent catalytic performance due to the synergistic effect of bimetal. Herein, a series of Rh 1-x Co x /Ni@Ni–N–C catalysts were prepared by an impregnation reduction method. The optimized Rh 0.75 Co 0.25 /Ni@Ni–N–C catalyst exhibited good catalytic performance with turnover frequency of 223.08 mol H2 mol cat −1 min−1 at 303 K, but decreased the catalytic performance compared with Rh/Ni@Ni–N–C. According to the XPS and Raman analysis, the RhCo alloy nanoparticles could be loaded at the defect position of Ni@Ni–N–C, and the Co nanoparticles occupied the intercalation between Rh and the defective site of the carrier, which could weaken the catalytic activity of AB hydrolysis. Based on the above research, we proposed the catalytic mechanism of the activation of the RhCo–H species. This work provides a new strategy for designing alloy-supported nano-catalysts. • The introduction of Co nanoparticles are occupied the position between Rh and defective site of Ni@Ni–N–C. • The introduction of Co nanoparticles reduce the catalytic activity of Rh/Ni@Ni–N–C. • The optimized catalyst Rh 0.75 Co 0.25 /Ni@Ni–N–C exhibits outstanding activity on hydrolysis of AB. [ABSTRACT FROM AUTHOR]

In the realm of new energy batteries, metal-air batteries and fuel cells exhibit promising prospects for broad market applications due to their high energy density, cost-effective manufacturing processes, and negligible atmospheric pollution. The oxygen reduction reaction (ORR) serves as a crucial cathode reaction in these battery systems. However, its relatively sluggish kinetics hinders the widespread adoption of such batteries. Therefore, efficient oxygen reduction catalysts are required to enhance the rate of ORR. Although traditional platinum (Pt) catalyst exhibits good electrocatalytic performance for ORR, it is difficult to be widely used because of its high cost and limited availability of resources. Alloy catalysts are anticipated to serve as substitutes for Pt catalysts by effectively enhancing catalytic activity while reducing production costs. Currently reported alloy catalysts in literature primarily augment their oxygen reduction activity through carbon carriers, heterojunction effects, amorphous structures or metal-organic framework-derived structures with heteroatom-doped composite alloys. This paper provides a comprehensive review on the research progress pertaining to Pt-based alloy catalysts, Pd-based alloy catalysts, and Fe-based alloy catalysts while summarizing the advantages and challenges associated with existing alloy catalyst systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Active learning enabled catalyst screening are conducted for alloy catalyst design. • Domain knowledge informed surrogate models are used to predict descriptors based on small datasets. • After only 3 iterations, 9 configurations are proposed as innovative catalysts from large searching space. • The work overcomes the contradiction of small sample and huge screen space for catalyst design. Alloy catalysts design faces the contradiction of small sample and huge screen space, especially in rational design with multi-objective and multi-constraints. Here, we conduct the active learning enabled innovative catalyst screening in alloy space composed of transition metal elements. First, the small dataset and large search space are constructed based on knowledge informed feature group. Then, the surrogate model based on Gaussian process regression are trained for predicting catalytic activity and N 2 selectivity descriptors for selective catalytic oxidation of ammonia (NH 3 -SCO) process, merely based on the small dataset. Furthermore, coupling pareto solution and Bayesian optimization, the active learning driven material searching are performed in the huge alloy spaces with more than 1000 configurations. After 3 iterations with high throughput calculation on 30 alloyed configurations and further theoretical validation based on microkinetic and stability analysis, 9 ensemble configurations are considered as innovative alloy catalysts of NH 3 -SCO with reactivity and selectivity trade-off. Our study provides the reliable framework for catalyst design with multi-objective and multi-constraints when facing with small sample data and huge searching space and gives the specific guidance for rational design of NH 3 −SCO alloy catalysts. [ABSTRACT FROM AUTHOR]

Carbon nanotubes loaded by different ratios of core-shell structured ruthenium platinum nanoparticles (Ru@ Pt/CNTs) were prepared by ethanol reduction methods and used as anodic catalysts for direct ethanol fuel cells. The structures of the as synthesized catalysts were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results show that Ru@Pt/CNTs nanoparticles formed a core-shell structure (the core was ruthenium and the shell was platinum). Meanwhile, the electrochemical measurements demonstrates Ru@Pt/CNTs exhibits ultrahigh electrochemical catalytic activity (Ru@ Pt0.75/CNTs, 1 767.77 mA/mg Pt) and durability (Ru@ Pt1.0 CNTs, CV decay of 19.7% after 250 test cycles) in ethanol electro-oxidation reaction ( EOR) compared with commercial Pt/C catalysts. Therefore, the Ru@ Pt/CNTs nanoparticles with core-shell structure have an excellent catalytic activity for ethanol oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface Pourbaix diagrams of Pt-Ru predict alloy segregation in formate oxidation. • Pt-dominated Pt-Ru surfaces tend to lose activity due to CO poisoning. • Ru dominance in surfaces enables mixed adsorbate layers and bi-functionality. • EXAFS data reflect changes in the adsorbate layer on the timescale of 1000 s. • Adsorbate layer composition in experiments agrees with theoretical predictions. Surface segregations of the Pt-Ru alloys are relatively fast. They are completed when the adsorbate reaches a composition related to potential. Surface phase diagrams based on density functional theory (DFT) calculations are used to identify stable surface phases present during the oxidation of fuel-cell-relevant organic compounds on Pt-Ru catalysts. The presence of adsorbed CO and O under operando conditions triggers changes in the local structure and composition of the metal alloy's surface. We find that a Ru-rich Pt-Ru surface stabilizes the mixed CO-O adsorbate phases that we expect to be most conducive to stable and efficient catalyst operation. The predicted surface structures and adsorbate coverages are confirmed by operando X-ray absorption spectra (XAS). [ABSTRACT FROM AUTHOR]

The fine regulation of catalysts by the atomic-level removal of inactive atoms can promote the active site exposure for performance enhancement, whereas suffering from the difficulty in controllably removing atoms using current micro/nano-scale material fabrication technologies. Here, we developed a surface atom knockout method to promote the active site exposure in an alloy catalyst. Taking Cu 3 Pd alloy as an example, it refers to assemble a battery using Cu 3 Pd and Zn as cathode and anode, the charge process of which proceeds at about 1.1 V, equal to the theoretical potential difference between Cu 2+ /Cu and Zn 2+ /Zn, suggesting the electricity-driven dissolution of Cu atoms. The precise knockout of Cu atoms is confirmed by the linear relationship between the amount of the removed Cu atoms and the battery cumulative specific capacity, which is attributed to the inherent atom-electron-capacity correspondence. We observed the surface atom knockout process at different stages and studied the evolution of the chemical environment. The alloy catalyst achieves a higher current density for oxygen reduction reaction compared to the original alloy and Pt/C. This work provides an atomic fabrication method for material synthesis and regulation toward the wide applications in catalysis, energy, and others., Competing Interests: Competing interests statement:The authors declare no competing interest.

A new metal-organic framework compound formulated as [Co 0.67 Zn 0.83 (btc)(H 2 O) 6 ] (1) was prepared and characterized by elemental analysis, and FT-IR spectroscopy. The single crystal analysis was used for determination of its structure. The complex was used for the preparation of two inorganic precursors [Co 0.67 Zn 0.83 (btc)(H 2 O) 6 ]/SiO 2 and [Co 0.67 Zn 0.83 (btc)(H 2 O) 6 ]/Al 2 O 3 , which were thermally decomposed to obtain new Co-Zn alloy catalysts for Fischer-Tropsch synthesis. The same catalysts were prepared by the conventional impregnation method as reference catalysts. The catalysts were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET specific surface area, and their catalytic performances were studied in the temperature range 200–300 °C and P = 5 bar. The results show that the Co-Zn synthesized alloy catalysts have acceptable activity in the Fischer-Tropsch (FTS) synthesis and have better selectivity to desired products than reference catalysts. The difference between the Co-Zn alloy catalysts and the reference catalysts is mainly caused by their different particle size. [ABSTRACT FROM AUTHOR]

The decisive aim of this work relies on studying the impact of catalytic reaction temperature on the physiognomies of the carbon nanotubes (CNTs) synthesized through the catalytic chemical vapor deposition (CCVD) technique. LaNi 5 Pt 0.5 alloy catalyst was employed to mediate the nucleation and growth of CNTs under three different reaction temperatures. Preliminarily, X-ray diffraction analysis and Raman spectroscopical investigation confirm the successful formation of carbon material under the reported reaction parameters. Further, the morphological diversity of CNTs produced through the influence of reaction temperature is verified through Field emission scanning electron microscopy and transmission electron microscopy. The CNTs were observed as helically coiled, Ni encapsulated, and hollow with a narrow cavity at 600 °C, 700 °C, and 800 °C respectively. Moreover, selected area electron diffraction analysis and energy dispersive X-ray analysis authenticated the aforementioned inferences. A detailed study of the growth mechanism based on the reaction temperature and its influences on the catalyst bed and decomposition of the carbon source is proposed. Finally, the prepared CNTs were distinguished through the magnetic coercivity values and the magnetic properties were studied. [Display omitted] • Synthesizing and characterizing platinum infused LaNi 5 intermetallic compound as catalyst. • Chemical vapor deposition of carbon nanotubes catalyzed by LaNi 5 Pt 0.5 intermetallic compound. • Studying impact of reaction temperature in the synthesis of morphologically different CNTs. • Investigating the structural magnetic properties of CNTs prepared at different temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel bimetallic Ni/Zn- PTA metal-organic frameworks with flower-like microsphere morphology has been designed and synthesized. • The developed Ni 3 ZnC 0.7 alloy catalyst exhibited excellent performance in the condensation cyclization reaction. • Excellent yields of 2-arylbenzimidazole derivatives were obtained. Developing efficient bimetallic Ni/Zn metal organic frameworks (MOFs) derived Ni 3 ZnC 0.7 alloy catalyst for cyclization reactions is highly anticipated. Bimetallic Ni/Zn- PTA MOFs with flower-like microspheres morphology was synthesized by using a facile hydrothermal method and used as a precursor for preparation of the catalyst. Then, a ZnO supported Ni-Ni 3 ZnC 0.7 incorporated carbon catalyst (Ni-Ni 3 ZnC 0.7 /ZnO-C) was obtained by deriving from the Ni/Zn- PTA MOFs through one-step pyrolysis. The developed Ni-Ni 3 ZnC 0.7 /ZnO-C catalyst was used as a recoverable heterogeneous catalyst for synthesis of 2-arylbenzimidazoles by cyclization reaction of phenylmethanamines and 2-nitroanilines in good yields. Various characterizations (e.g. SEM/EDX, XRD, TEM, FT-IR, XPS and Raman) revealed that the catalyst exhibited good performance for cyclization reaction, which are ascribed to particular hierarchical structure, as well as synergistic effect between Ni and Ni 3 ZnC 0.7. As a result, the Ni-Ni 3 ZnC 0.7 /ZnO-C catalyst showed excellent stability and activity for the condensation cyclization reaction. This bimetallic MOFs-derived Ni-Ni 3 ZnC 0.7 catalyst opens up a potential way for fabricating other Carbon supported alloy catalysts in heterogeneous catalysis reactions. [ABSTRACT FROM AUTHOR]

Large-scale and whole hexagonal diamond silicon nanowires (h-SiNWs) were synthesized with aluminum-gold (Al–Au) alloy-catalytic assistance to reduce the nucleation barrier by regulating the chemical potential. Here, we demonstrate the effect of the catalyst on the structure in silicon nanowires by correlating the experimental observations with a theoretical interpretation based on thermodynamics. It was found that high chemical potential is necessary to enhance the nucleation of the hexagonal diamond phase, and the addition of Al into the Au catalyst can increase the supersaturation of silicon atoms in the catalyst and reduce the contact angle of solid-liquid to tune the chemical potential. When the supersaturation is high enough and the alloy catalyst is almost perpendicular to the top of the nanowire, the hexagonal diamond phase is more likely to appear than the cubic phase, whereas others are not. Additionally, a 1319 nm photodetector was fabricated using the h-SiNWs network with a smaller band gap and a lower conductivity compared with cubic silicon nanowires (c-SiNWs), whose dark current is as low as 5.03 × 10 −12 A with a high responsivity of 0.5 A⋅ W −1 at an applied bias of 1 V. • Large-scale hexagonal diamond nanowires were synthesized by thermal evaporation method. • The supersaturation and the interface energy are two key factors for synthesizing hexagonal diamond silicon. • A detector was prepared for 1319 nm and its dark current is as low as 5.03 × 10 −12 A with a high responsivity of 0.5 A⋅ W −1. [ABSTRACT FROM AUTHOR]

Recently various supported bimetallic catalysts have been employed as effective catalysts for γ-valerolactone (GVL) production from levulinic acid or its esters. However, previous reports have shown synergetic roles of active metals and supports as important keys for superior catalytic performance. This work combines both experimental and simulation studies to focus solely on the role of bimetallic formation between nickel (Ni) and copper (Cu). The experimental results suggest that both Ni and nickel-copper alloy (NiCu) catalysts are good for hydrogenation of methyl levulinate (ML) to an intermediate species, 4-hydroxypentanoic acid (HPA). However, only NiCu has a better tendency to accelerate the conversion of HPA to GVL via cyclization process. Activation energy from experimental study of cyclization step over Ni is about two times larger than that of NiCu (E a K 2 values are 121.7 and 56.0 kJ mol K−1 for Ni and NiCu, respectively) provided strong evidence of superior GVL production over NiCu catalyst. Density Functional Theory (DFT) simulation results reveal solid finding to support the high efficiency of NiCu over Ni catalyst for GVL production. The calculated energy barrier for HPA conversion to GVL over the NiCu is 1.0 eV which is lower than that of the Ni catalyst (1.54 eV). The Ni provided only one concerted pathway to transform from ML to GVL, while NiCu could provide either a concerted or nonconcerted pathway where the latter one requires lower activation energy for GVL production. The combination of these experimental and simulation results leads to a better understanding of bimetallic catalyst design for GVL production via catalytic transfer hydrogenation without any support materials. [Display omitted] • Unsupported NiCu alloy catalyst drastically enhances GVL production. • Cyclization process is the distinguishing step between Ni and NiCu alloy catalysts. • The NiCu alloy catalyst could generate GVL yield up to 75% at 140 °C. • Non-concerted pathway is the preferential route for GVL production. [ABSTRACT FROM AUTHOR]

Designed alloy catalysts have shown promise in structure-controlled growth of single-wall carbon nanotubes (SWCNTs). However, due to the high-dimensional growth parameter space and low efficiency of the conventional trial-and-error optimizing approach, it is still challenging to explore and to establish the relations between catalyst compositions and the structure of SWCNTs. Here, we present a high-throughput strategy to investigate the statistical patterns in catalyst activity and selective growth of SWCNTs using Co/Pt/Mo ternary catalysts. Statistical analysis reveals that in the Co/Pt/Mo ternary diagram, there is an active region in the Co-rich Co–Mo corner to grow SWCNTs with high yield (≥25 tubes/μm2) and high quality (I G / I D ≥ 40). Enriched semiconducting (s-) SWCNTs with a purity higher than 90% were obtained along the boundary of the high yield region, near the Co–Pt axis. The statistical patterns of the yield, quality and selectivity are associated with the alloy composition, revealing a negative correlation between the yield and enrichment of s-SWCNTs. High-resolution transmission electron microscope characterization shows that a Co–Pt alloy catalyst with a uniform size distribution facilitates the s-SWCNT enrichment. And the separate phases of a Co–Mo/Co catalyst stabilize the active Co phase, leading to long catalyst lifetime and high yield of SWCNTs. A high-throughput strategy is developed to investigate the statistical patterns of the catalyst activity and the selective growth of single-wall carbon nanotubes (SWCNTs) grown from Co/Pt/Mo ternary catalysts. The structure of Co/Pt and Co/Mo catalysts linked with SWCNTs are further identified by using high-resolution transmission electron microscope. [Display omitted] [ABSTRACT FROM AUTHOR]

The preferred Pt counter electrode (CE) has been an economic burden for commercialization of dye-sensitized solar cells (DSSCs). To address this issue, we present here the fabrication of a series of hollow PtNi alloy CEs tailored with ZnO micro/nanostructures. The preliminary results demonstrate that alloyed PtNi electrode displays markedly increased performances in transporting charges, catalyzing redox electrolyte, and remaining persistent stability under long-term operation in comparison with standard Pt electrode. The optimized liquid-junction DSSC device from PtNi 1.07 CE yields a maximal power conversion efficiency of 9.08%, suggesting a 43% enhancement compared with 6.35% for Pt based photovoltaics. [ABSTRACT FROM AUTHOR]

Interaction of biogenic impurities with the Ni (1 1 1) catalyst surface was studied to understand their important role in inhibiting catalysis. Non-bonding interactions of amino acids (Alanine (Ala), Cysteine (Cys), Methionine (Met), Tryptophan (Trp), Histidine (His), Lysine (Lys), Glutamic acid (Glu) and Threonine (Thr)) in aqueous environment were examined using classical molecular dynamics (MD) simulations. The potential of mean force (PMF) profiles of amino acids revealed qualitative differences, resulting into altered orientation and the choice of preferential interacting site with the metal surface. The side chains of all the amino acids were observed to align parallel to the metal surface. Amino acids containing sulfur (Met and Cys) and heterocyclic nitrogen (Trp, His) were observed to interact favorably with the Ni surface. Most of the preferential interacting sites were observed to be in direct contact with the surface except Lys which interacted with the backbone nitrogen oriented away from the surface. The strength of non-bonded interactions varied from −13 to −71 kJ/mol with Ala as the weakest and Trp as the strongest interacting amino acids. The interaction energies scaled linearly with the solvent accessible surface area of the amino acids. Density functional theory (DFT) calculations were utilized to understand the bonding interactions of sulfur (S) containing amino acids (Met and Cys) and the irreversible catalyst deactivation caused by them. DFT calculations showed strong binding for both Cys (−123 kJ/mol) and Met (−115 kJ/mol), undergoing dissociation to form atomic S on the Ni (1 1 1) surface with an intrinsic activation barrier of 32 kJ/mol and 133 kJ/mol, respectively, for the C S bond cleavage. However, the mechanistic routes for dissociation followed by the two amino acids were a bit different. While in Cys, the C-H activation was followed by C S cleavage, in Met, C S bond was activated first to form S-CH 3 species on the catalyst surface. In contrast to Met at higher coverage, Cys was observed to decompose to elemental S on the surface. The mechanistic insights thus obtained lead to an explorative theoretical framework for the design of a bimetallic catalyst, which may be used in an integrated bio and chemo-catalytic process with reduced chances of deactivation. The Ni-Au alloy surface showed lower binding energies for both Met (−88 kJ/mol) and S (−132 kJ/mol), as compared to pure Ni surface, indicating promising prospects for the activity of such an alloy catalyst. [ABSTRACT FROM AUTHOR]

There is increasing demand for versatile catalysts for direct hydrocarbon utilization with the coming of hydrocarbon economy. The catalysts are required to possess both high catalytic activities and excellent carbon coking tolerance for the hydrocarbon oxidation process. In this regard, we considered Ni-based alloy catalysts, e.g . Ni-Co, Ni-Cu, and Ni-Fe, which are expected to provide synergistic effects from the high catalytic activities of Ni and the high carbon coking tolerance of transition metals. We conduct a systematic investigation of catalytic effects on the electrochemical properties and the carbon coking tolerance of the candidates. Moreover, the binding strengths of H, O, and C species with each alloy catalyst were examined via density functional theory (DFT) calculations, providing insight into the trend of catalytic activity and carbon coking tolerance. In this study, the single cell for the solid oxide fuel cell with Ni-Fe catalyst shows the best electrochemical performance, 0.81 and 0.30 W cm −2 at 700 °C under H 2 and C 3 H 8 , respectively, with excellent tolerance against carbon deposition. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFT was used to model the atomic segregation of Pt-skinned Pt-M (M = Ni, Co, Ir). • Electrochemical environment was simulated based on electrical double layer effects. • PEMFC operating conditions were considered for evaluating the catalyst durability. • Pt/PtNi and Pt/PtCo catalysts are very resistant to atomic segregation. • Pt/PtCo is best suitable for PEMFC cathode due to its ORR efficiency and durability. Pt-skinned Pt-M (M = Ni, Co, and Ir) alloy catalysts have been reported as cathode catalysts for polymer electrolyte membrane fuel cells (PEMFCs) that are durable and highly efficient toward the oxygen reduction reaction (ORR). While density functional theory (DFT) studies have confirmed that these catalysts are efficient, they did not clearly demonstrate the superior durability imparted by the Pt-skin layer. Herein, we introduce an atomic segregation model based on density functional theory calculated (DFT-calculated) vacancy formation energies that overcomes these limitations. Solvation-corrected segregation energies reveal that the Pt/PtNi(1 1 1), Pt/PtCo(1 1 1), and Pt/PtIr(1 1 1) surfaces, which can contain very low amounts of Pt, are highly resistant to atomic segregation from the alloy catalyst. The influence of the Pt-skin layer of the examined Pt/PtM catalysts was closely investigated by considering the PEMFC operating conditions, including solvation, the oxygen-rich environment of the cathode, the electrical double-layer, pH, potential, and temperature. As a result, we demonstrated that the Pt/PtCo catalyst exhibits superior durability with a high vacancy formation energy for the Pt-skin layer. [ABSTRACT FROM AUTHOR]

The catalyst layer (CL) is the only electrochemical reaction site in proton exchange membrane fuel cells (PEMFCs), decisive in their performance. Herein, a mild and simplified strategy is implemented into the in-situ growth of Pt–Pd alloy catalysts on the gas diffusion layer (GDL) as the CLs for PEMFCs. Pt/C is used as the nucleation site to assist the in-situ growth of the Pt–Pd CL. The as-prepared Pt–Pd CL behaves as a multi rhombic-pyramidal structure, which are evenly distributed on the GDL surface. The effect of the Pt/Pd atomic ratio on the electrocatalytic activity is investigated through a single-cell performance test, and the optimal atomic ratio is determined to be 1/2, which exhibits excellent cell performance and low activation polarization loss. Meanwhile, the single-cell test results reveal that Pt 1 Pd 2 CL reaches optimal performance at a loading of 0.122 mg cm−2 (∼0.06 mg Pt cm−2), with a peak Pt-specific power density of 14.23 W mg−1 (6.81 W mg−1 in PtPd), approximately 3.96 times that of a commercial Pt/C CL (0.2 mg Pt cm−2). Furthermore, Pt 1 Pd 2 CL shows significantly better stability than the commercial Pt/C CL, indicating that the in-situ preparation of the Pt-based CL has an excellent prospect for the commercial development of PEMFCs. [Display omitted] • In situ grown Pt–Pd CL is developed for PEMFC operation. • The Pt–Pd CL exhibits a multi rhombic-pyramidal structure with high active sites exposure. • The Pt–Pd CL maintained high electrocatalytic activity with reduced Pt loading. • The resultant PEMFC shows excellent performance and stability. • The peak Pt-specific power density was up to 14.23 W mg−1 (6.81 W mg−1 in PtPd). [ABSTRACT FROM AUTHOR]

Pt counter electrode (CE) has been a burden for the commercialization of liquid-junction dye-sensitized solar cells (DSSCs). In searching for cost-effective CEs without sacrificing electrochemical activities, here we report the experimental realization of ZnO nanorods assisted Ni 1.1 Pt and Co 3.9 Pt alloy microtube (MT) CEs by combining a simple electrodeposition deposition on aligned ZnO nanorods and a galvanic displacement reaction. On behalf of the good charge-transfer ability along one-dimensional alloy electrocatalyst and electrocatalytic activity toward liquid electrolyte, the resultant DSSCs with Ni 1.1 Pt and Co 3.9 Pt MT CEs display promising power conversion efficiencies of 8.29% and 7.73%, yielding 30.6% and 21.7% enhancements, respectively. Similarly importantly, the alloyed CEs are still scalable, other alloyed low-Pt or non-Pt nano/microstructures can also be realized using the method reported here. [ABSTRACT FROM AUTHOR]