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Compared to conventional Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF) and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF), BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ (BCFZY) with special surface species and structure can exhibit a distinctive compromise between the redox activity and cell stability. The X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (TPD) and infrared spectrum (IR) results suggest that besides the oxygen species of BSCF and LSCF, the OH-related species can be detected on BCFZY, which can play a promoting role in oxygen catalysis activity. The O2− -conducting solid oxide fuel cell (SOFC) with BCFZY cathode shows the superior power densities at intermediate temperatures (750-650 °C), which are 1.2–1.6 times than those of BSCF cell, and 1.8–2.1 times than those of LSCF cell. Distribution of relaxation times (DRT) analysis on three symmetric cells and three single cells reveal that BCFZY cathode shows superior oxygen adsorption and dissociation, which can be ascribed to the peculiar OH-related species and multiscale structure on the surface. The cell with BCFZY cathode can remain the stable performance during the discharge testing at 650 °C for 240 h, indicating a reliable surface state to promote both oxygen catalysis activity as well as the performance stability for O2− -conducting SOFC. • BCFZY demonstrates considerable activity vs BSCF and LSCF on O2--conducting SOFC. • BCFZY cell achieves high power density (1.99–1.40 W cm−2) at 750-650 °C. • BCFZY cathode exhibits superior oxygen exchange processes on surface. • The special surface state of BCFZY cathode improves O 2 catalysis and stability. [ABSTRACT FROM AUTHOR]

• Two (Ba, Sr/Sm)(Co, Zr)O 3-δ composites are prepared via a smart co-assembled method. • Two composite show good thermal properties and nanostructure to extend active area. • Two co-assembled composites show excellent cell performance as IT-SOFC cathodes. • The BSmCZ cell shows better oxygen catalysis activity at the intermediate temp range. The cobalt-based perovskites are the most common solid oxide fuel cell (SOFC) cathode materials, which generally have the issues of thermal compatibility and performance at the reducing temperature. In this study, two Ba 0.5 (Sm/Sr) 0.5 Co 0.8 Zr 0.2 O 3-δ (BSmCZ/BSrCZ) perovskite composites were synthesized using a smart co-assembled method, which were primarily composed of cubic doped-BaZrO 3 and hexagonal doped-BaCoO 3 perovskites. Both BSmCZ and BSrCZ composites exhibited more suited thermal expansion coefficient (12.8 × 10-6 and 13.9 × 10-6 K−1) to the electrolyte, nanostructure with extensive heterointerfaces and excellent cathode|electrolyte interfaces. Compared to BSrCZ composite, the BSmCZ composite possessed a relatively higher content (65 %) of activated oxygen species and higher electrical conductivity (70.7 S cm−1). The cells with two composite cathodes could achieve the remarkable maximum power density, especially for BSmCZ composite cathode of 2.00–1.11 W∙cm−2 at 800–650 °C. The electrochemical analysis revealed that the BSmCZ composite cathode demonstrated the enhanced surficial oxygen catalysis processes, which could benefit from the active oxygen species and heterointerface. [ABSTRACT FROM AUTHOR]

A series of Bi2Sn2O7 photocatalysts was developed with the aim to regulate defect chemistry as well as electronic structure by modulating the charge states of tin species for boosting photocatalytic selective oxidation of alcohols performance. Defective centers, such as oxygen vacancies (OVs), were beneficial to enhancing the adsorption and activation of molecular oxygen. Meanwhile, the valence band edge potential of Bi2Sn2O7 with higher OVs content exhibited a distinct downshift, improving the thermodynamical driving force of photooxidation. Additionally, OVs contributed to promoting the separation efficiency of photogenerated carriers, which can be confirmed by the surface photovoltage measurement. By optimizing the electronic structure as well as defect chemistry, the optimal benzyl alcohol conversion efficiency was 76.0 % with selectivity toward benzaldehyde being about 100 %. It's found that photogenerated holes and.O2− active species played critical role in photocatalytic aerobic oxidation. This work may provide a novel insight to clarify the role of defect chemistry during the selective benzyl alcohol oxidation over Bi2Sn2O7 photocatalyst. [ABSTRACT FROM AUTHOR]

Pt/WO3-NaTaO3 composite catalysts for different W/Ta molar ratios were obtained via a facile hydrothermal method. The WO3-NaTaO3 heterojunction was constituted and could be regulated by the adjustment of the W : Ta ratio, as confirmed by multiple characterizations. Due to the favorable CO anti-poisoning characteristics ascribed to the sufficient surface –OHad provided by both WO3 and NaTaO3, excellent stability of the WO3-NaTaO3 composite in acidic and alkaline environments, and charge transfer from metal oxide to Pt, the as-obtained Pt/WO3-NaTaO3 composite catalyst could exhibit desirably high electrocatalytic performances. As a result, the as-prepared Pt/WO3-NaTaO3 (W : Ta = 3 : 1) and Pt/WO3-NaTaO3 (W : Ta = 0.2 : 1) products exhibited optimal performances in the methanol oxidation reaction (MOR) process in acids and alkalis, respectively, as compared to those of commercial Pt/C, Pt/NaTaO3, and Pt/WO3 catalysts. In particular, in acidic and alkaline environments, the highest electrocatalytic activity of Pt/WO3-NaTaO3 catalyst could reach three times that of commercial Pt/C and its stability could reach more than five times that of commercial Pt/C. Density functional theory calculations further proved the enhancement of WO3 with regard to methanol electrooxidation. [ABSTRACT FROM AUTHOR]

A novel catalyst, CeO2@Ag/Ag2Ta4O11, was successfully assembled via an in situ catalytic process for 4-nitrophenol reduction. As-prepared samples were characterized using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray spectroscopy (XPS), and ultraviolet-visible diffuse reflection spectroscopy (DRS). The results showed the elementary substance Ag was produced from Ag2Ta4O11 after a circular reduction reaction and was homogeneously deposited on the surface of Ag2Ta4O11 nanoparticles, which were wrapped by octahedron-shaped CeO2. The as-prepared nanocomposites exhibited extremely accelerated catalytic activity toward the efficient reduction of 4-nitrophenol compared to pure CeO2 and Ag2Ta4O11 nanoparticles. 15 rounds of recycling experiments confirmed that the samples exhibited good reuse stability, assigned to the confined robust shield of CeO2. The shell of CeO2 efficiently prevented undesirable aggregation and leaching of Ag nanoparticles. The persistent ascending activity with an increasing number of experimental runs was related to the amount of metallic Ag gradually growing. Moreover, it was proposed that the active interfacial contact between ceria oxide/metallic Ag/the semiconductor Ag2Ta4O11 (CeO2@Ag/Ag2Ta4O11) in the core–shell structure facilitated the transfer of electrons, contributing to the enhanced activity. [ABSTRACT FROM AUTHOR]

The present work reports the preparation of a short-ordered Na xTaO y ⋅ n H2O catalyst that exhibits exceptional and highly efficient photocatalytic reactivity toward aerobic oxidation relative to its crystalline counterpart. Synchrotron radiation wide-angle X-ray scattering and transmission electron microscopy results indicated that the as-synthesized catalyst shows short-ordered features with well-controlled short-range ordering limits and defect chemistry. The short-ordered structure of Na xTaO y ⋅ n H2O predicted large amounts of defective centers and high surface areas that may play critical roles in visible-light harvesting and photocatalytic aerobic oxidation. This work may provide a novel strategy for the development of short-ordered catalytic systems with well-controlled defect chemistry that exhibit highly efficient photocatalytic properties. [ABSTRACT FROM AUTHOR]

PtCo alloy@cobalt benzoate/graphene (PtCo@Co‐BA/Gr) composite catalyst with 0D/1D/2D multidimensional structure is presented with simple solvothermal approach. As the introduced critical carrier, benzoic acid cobalt (II) (Co‐BA) has porous channels matching the size of platinum (Pt) nanoparticles and can enable PtCo alloy particles to be formed in its 1D mesopores through in situ reduction. Experiments indicate that the hydroxyl (OH) groups on the outer surface of Co‐BA are beneficial to form a strong interaction between Co‐BA and graphene. Compared with commercial Pt/C catalyst, the prepared PtCo@Co‐BA/Gr composite catalysts display an enlarged electrochemically active surface area, enhanced catalytic activity, and prolonged durability in acidic media toward the oxidation of various alcohols, such as methanol, ethanol, and ethylene glycol, which is mainly due to the increased surface area of PtCo by the confinement of mesoporous Co‐BA fiber, the promotion of water molecule dissociation of Co‐BA skeleton, and the improvement of conductivity by the introduction of graphene. [ABSTRACT FROM AUTHOR]

• Supported catalysts with Pt cubes, spheres and tetrahedrons have been prepared. • Effects of size, support, surfactant and metal-support interaction are minimized. • Catalyst with Pt nanocubes with (1 0 0) facets exhibits the highest catalytic activity. • The adsorption affinity of O 2 and glycerol over different Pt facets alters activity. • Superior anti-deactivation ability is also found on Pt(1 0 0) facets. Using nanocrystals with specific crystal facets is an effective way to enhance activity and selectivity for numerous catalytic reactions. However, the intrinsic facet effect is not fully understood. Herein, using Pt catalyzed glycerol oxidation reaction as the model system, the intrinsic facet effect on catalytic property is evaluated by three kinds of Pt nanocrystal catalysts with cubic, spherical and tetrahedral shapes. Size effect, support effect, surfactant effect as well as the metal-support interaction of the catalysts are avoided to the maximum extent. The supported Pt nanocubes enclosed by Pt(1 0 0) facets are found to exhibit much higher catalytic activity and stability for the aerobic oxidation of glycerol than catalysts with Pt nanotetrahedrons enclosed by Pt(1 1 1) facets. DFT calculations indicate that the adsorption of oxygen and glycerol would materialize easier on Pt(1 0 0) than on Pt(1 1 1). Furthermore, Pt(1 0 0) may prevent deactivation caused by product adsorption as well. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ag/Bi°-BiVO 4 catalysts with multi-active sites were fabricated toward high-efficient reduction of aromatic nitrobenzene. • The catalysts presented excellent catalytic activity and good stability to 4-NP reduction. • The BiVO 4 , Bi° and Ag offered multi-active sites to synergistically act on the reduction of nitrophenol. Abstract In this work, we report on the preparation of silver nanoparticles modified bismuth/bismuth vanadate (Bi°-BiVO 4) catalyst with multi-active sites toward efficient reduction of aromatic nitrobenzene, aiming to tailor the synergistic effects of multi-active sites and specify the underlying catalytic mechanism. The as-prepared catalysts were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray and X-ray photoelectron spectroscopy. It is observed that Ag nanoparticles with diameter of ˜30 nm were anchored evenly on the surface of rod-shaped BiVO 4 , which offered multi-active sites to contact with the reactants effectively and transfer interfacial electron to 4-nitrophenol (4-NP) rapidly. The activity factor k of Ag/Bi°-BiVO 4 for 4-NP reduction is estimated to ˜3933.4 min−1 g−1, which is much higher than that obtained from pristine BiVO 4 catalyst, Bi° and noble metal Ag nanoparticles. According to the experimental results, the reaction mechanism and reaction path of 4-NP reduction for BiVO 4 , Bi and Ag were studied through the density functional theory (DFT) theoretical calculation, which suggested that they exhibit synergistic catalytic effect in the reaction process. This work may provide a feasible foundation for the mechanism research of semiconductor reduction to 4-nitrophenol. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Co@NCNT and Ni@NCNT catalysts were synthesized using the calcination method. • The Co@NCNT and Ni@NCNT catalysts exhibited good electrocatalytic activity for the ORR. • Their electrocatalytic activity of both catalysts was due to the rich N-doped active C sites. • The good catalytic activity was also due to synergistic reaction between Co (Ni) and NCNTs. Electrocatalysts based on nanosized cobalt or nickel particles encapsulated by nitrogen-doped carbon nanotubes (M@NCNTs (M = Co or Ni)) were synthesized using the calcination method. They were served as the catalyst toward an oxygen reduction reaction (ORR). The results implied that the M@NCNT electrocatalysts had ORR catalytic activity in an alkaline electrolyte. The half-wave potential (E 1/2) on the Co@NCNT catalyst reached 0.881 V, which was higher than for commercial Pt/C (0.856 V). The M@NCNT electrocatalysts exhibited good stability in the ORR. After 3000 cycles, the E 1/2 for the Co@NCNTs was almost completely unchanged, whereas for the Ni@NCNTs, shifted negatively to 19 mV, was less than for commercial Pt/C (34 mV). These promising electrochemical properties were due to abundant active carbon sites and the synergistic reaction between Co/Ni and NCNTs. Density functional theory calculations indicated that the OOH had strong absorption on the C atoms (adjacent to pyridinic N) in the Co@NCNT and Ni@NCNT catalysts. [ABSTRACT FROM AUTHOR]

AgTaO 3 /AgBr heterojunction was constructed for visible light driven photocatalytic purpose in order to investigate the relevance of phase conversion, electronic structure and photocatalytic properties. The result indicated that AgBr grafted on AgTaO 3 to form AgTaO 3 /AgBr heterojunction gave intense visible light absorption, which exhibits highly enhanced photocatalytic performance than their individual counterpart. Theoretical and experimental investigation showed that the matched electronic structure between AgTaO 3 and AgBr induced an efficient transfer of photogenerated electrons from AgBr to AgTaO 3 , leading to efficient charge separation and the subsequent improved photocatalytic activity. Partial AgBr converted to AgBr/Ag during the photocatalytic process, leading to the construction of ternary AgTaO 3 /AgBr/Ag photocatalyst. Because of the surface plasmon resonance effect of Ag, the resulting AgTaO 3 /AgBr/Ag exhibited wide range absorption and improved charge separation efficiency, which showed high durability and superior photocatalytic activity toward methyl orange degradation. On the basis of spin resonance measurement and trapping experiment, it is expected that photogenerated electrons, O 2 − , and OH active species dominate the photodegradation of methyl orange. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Fe 3 C@NCNTs was successfully synthesized using one-step calcination method. • The Pd nanoparticles were loaded onto the surface of the Fe 3 C@NCNT electrocatalyst. • The synergistic effect of Pd enhanced the catalytic activity of the Pd/Fe 3 C@NCNTs. • The Pd/Fe 3 C@NCNT electrocatalyst had excellent catalytic activity for ORR and EOR. • The electrocatalytic activity of Pd/Fe 3 C@NCNTs was superior to commercial Pd/C and Pt/C. Iron carbide-encapsulated nitrogen-doped carbon nanotubes (Fe 3 C@NCNTs) and Pd that is loaded onto Fe 3 C@NCNTs (Pd/Fe 3 C@NCNTs) electrocatalysts were synthesized. The valence state of Pd that was loaded onto the Pd/Fe 3 C@NCNTs surface is in the Pd0 and Pd2+ forms and Pd0 is the main form. The electrochemical measurement results imply that the Fe 3 C@NCNT catalyst exhibits an electrocatalytic property in the oxygen reduction reaction (ORR). The Pd/Fe 3 C@NCNT electrocatalyst has a good catalytic property toward ORR and ethanol oxidation reaction (EOR) in an alkaline solution. The half-wave potential (E 1/2) on the Pd/Fe 3 C@NCNT electrocatalyst toward the ORR can reach 0.904 V, which is higher than that on commercial 20 wt% Pt/C (0.856 V). The forward oxidation peak current density (j f) on the Pd/Fe 3 C@NCNT electrocatalyst for ethanol oxidation is 1.655 A mg−1, which is larger than that on commercial 10 wt% Pd/C (0.430 A mg−1). The excellent electrocatalytic property of the Pd/Fe 3 C@NCNT electrocatalyst is contributed to the many active sites and synergistic effects between Pd and Fe 3 C@NCNTs. The density functional theory (DFT) calculation result implies that the electron mobility increases in the recombination area for Pd and Fe 3 C@NCNTs. [ABSTRACT FROM AUTHOR]

This work reported on the synthesis of a series of nitrogen doped Ca 2 Nb 2 O 7 with tunable nitrogen content that were found to be efficient and green noble-metal-free catalysts toward catalytic reduction of p -nitrophenol. XPS and ESR results indicated that the introduction of nitrogen in Ca 2 Nb 2 O 7 gave rise to a large number of defective nitrogen and oxygen species. Defective nitrogen and oxygen species were found to play synergetic roles in the reduction of p -nitrophenol. The underlying mechanism is completely different from those reported for metallic nanoparticles. Moreover, the more negative conduction band edge potential enabled nitrogen doped Ca 2 Nb 2 O 7 to show photo-synergistic effects that could accelerate the reduction rate toward p -nitrophenol under UV light irradiation. This work may provide a strategy for tuning the catalytic performance by modulating the chemical composition, electronic structure as well as surface defect chemistry. [ABSTRACT FROM AUTHOR]

[Display omitted] • CTF with Fe incorporation was used to prepare a series of Fe/TTF electrocatalysts. • Fe/TTF-0.5-900 exhibited the optimal catalytic activity in ORR process. • The MPD of MFC with Fe/TTF-0.5-900 cathode reached up to 2617 mW·m−2. • DFT confirmed that Fe 3 C accelerated the break of O-O bond in *OOH. The low power output of microbial fuel cell (MFC) requires high-performance catalysts to facilitate cathodic oxygen reduction reaction (ORR). In this work, a series of electrocatalysts (Fe/TTF) are synthesized by thermalizing N-rich covalent triazine framework (CTF) with various amount of FeCl 3 ·6H 2 O at different calcination temperatures for ORR catalysis in MFC. Electrochemical measurements reveal that Fe/TTF-0.5-900 synthesized with a mass ratio of 1:2 (FeCl 3 ·6H 2 O: CTF) at 900 °C exhibits the minimum charge transfer resistance and optimal catalytic behavior in ORR process. The MFC with Fe/TTF-0.5-900 cathode displays a high maximum power density of 2617 mW·m−2, which surpasses those of other Fe/TTF electrocatalysts, thermalized covalent triazine framework (TTF) and the benchmark activated carbon (AC). The results indicate that TTF as a porous carbon matrix with favorable nitrogen doping promotes charge and mass transfer greatly, and the combination of iron carbide substantially benefits the improvement of MFC performance. Moreover, according to density functional theory (DFT) calculation, iron carbide is significantly preferable for ORR catalysis by accelerating the break of O-O bond in *OOH, which further reveals that the ORR on iron carbide follows four-electron pathway. Therefore, Fe/TTF-0.5-900 can be applied as an economical and highly active electrocatalyst in MFC to achieve high-efficiency energy conversion. [ABSTRACT FROM AUTHOR]

• The TaN-TaC composite with a large specific area was successfully prepared. • The uniform Pd nanoparticles were loaded onto the surface of TaN-TaC composite. • Pd loading enhanced the electron transfer between Pd and TaN-TaC composite. • The Pd/TaN-TaC exhibited a high electrocatalytic activity for EG oxidation. • The electrocatalytic activity of Pd/TaN-TaC was superior to commercial Pd/C 10%. In this work, tantalum nitride and tantalum carbide (TaN-TaC) composites are prepared using a one-step calcination method. The resulting TaN-TaC composites have excellent conductivity, and therefore, potential applications in the electrode materials of fuel cells. Then, palladium nanoparticles loading on TaN-TaC (Pd/TaN-TaC) electrocatalysts are synthesized using the reflux method. The X-ray photoelectron spectroscopy results imply that the valance states of palladium are of the form Pd0 and Pd2+ on the surface of TaN-TaC composites. The electrocatalytic activity of the Pd/TaN-TaC catalysts is measured in a 0.5 mol L−1 KOH solution and 1 mol L−1 of ethylene glycol. These results imply that the Pd/TaN-TaC electrocatalyst modified glassy carbon electrode has a high catalytic activity for ethylene glycol electrooxidation in an alkaline medium. The dosage of Pd is 7% (mass ratio of Pd and TaN-TaC) and it exhibits the higher electrocatalytic activity, and superior to the commercial Pd/C (10%). [ABSTRACT FROM AUTHOR]

Pt/TaON|N-rGO composite with targeted growth of Pt at the heterojunction of TaON|N-rGO exhibited high catalytic activity, excellent CO-tolerance and long-term durability for EG oxidation in acid due to the optimal ternary synergy. • TaON/N-rGO was obtained by the calcination of layered supramolecules. • Pt was induced by defects and loaded at TaON|N-rGO junctions. • Pt/TaON|N-rGO electrode exhibited optimal performances in EGOR. • The improved performance was due to the synergy in the ternary interface. For platinum (Pt) composite electrocatalysts formed by multiple components, the selective growth of Pt on oxygen-containing species can maximize the CO-resistance and durability, which is a big challenge in interfacial science. In this paper, Pt/TaON|N-rGO composite was obtained by an in-situ calcination of a layered supramolecule self-assembled by TaCl 5 , urea and n-butanol, followed with the targeted growth of Pt nanoparticles induced by the defects at the junction of TaON|N-rGO. As a result, Pt/TaON|N-rGO electrode with the ideal ternary interface of Pt|TaON|N-rGO exhibited exceptionally high catalytic mass activity (250.6 mA·mg−1Pt), excellent CO-tolerance (I f /I b = 1.6 normalized to Pt/C) and long-term durability (136.4 mA·mg−1Pt after continuous 1200 min operation) for EG oxidation in acid, compared to commercial Pt/C (57.8 mA·mg−1Pt). The promoted performance was attributed to the synergies at ternary interface of Pt|TaON|N-rGO, and the boosting CO-tolerance was achieved by the shortened L-H pathway ascribed to the selective growth of Pt nanoparticles on the heterojunction of TaON|N-rGO. [ABSTRACT FROM AUTHOR]

The conversion of the heavy concentration of nitroarenes into their corresponding non-toxic aminoarenes is very meaningful for both environment and industrial applications. In this study, a series of Cu 2 O/SrTiO 3 nanocomposites and further Cu 2 O/Cu/SrTiO 3 via Cu+ reducing in situ during the reactive proceeding were fabricated and applied to reduce nitroarenes. The as-prepared composites present high reductive activity and reusable stability for 4-nitrophenol both under the continuous multi-batch ways and flow conditions. The test in an enlarged level revealed 4-nitrophenol (10 L, 0.01 mol L−1) could be quickly conversed to 4-aminophenol over the as prepared sample (300 mg) within 1 h under continuous flow conditions by a self-designed device. The mechanism investigation proposed that Cu0/Cu+1 pairs serve as a hydrogen and electron transferred shuttle to promote the reductive ability while SrTiO 3 as a protective agent packs up tetrakaidecahedron Cu 2 O to achieve a substantial increase in the stability of the catalyst. The existence of a Cu 2 O–Cu–SrTiO 3 three-phase interface in the hybrid is proved to play the key roles in the greatly enhanced electron transfer ability and the better catalytic activity. The present investigation indicates that the as-prepared samples may be effective and potential materials for the cleaner and sustained conversion of nitroarenes to aminoarenes on a lab level as well as a larger scale. The prepared Cu 2 O/Cu/SrTiO 3 hybrid is cost-effective and environmentally friendly catalyst towards heavy concentrations of nitroarenes to aminoarenes in which the in situ generated Cu0/Cu+1 shuttle plays the key role for the greatly durable catalytic ability. Image 1 • Cu 2 O/Cu/SrTiO 3 was prepared via Cu+ reducing in situ in Cu 2 O/SrTiO 3 nanocomposite during the reactive proceeding. • Continuous conversion of high concentrations of 4-NP illustrates the potential for a larger scale in industrial application. • Cu0/Cu+1 pairs serve as a hydrogen and electron transferred shuttle to promote the catalytic ability. [ABSTRACT FROM AUTHOR]