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H2 generation by solar water splitting is one of the most promising solutions to meet the increasing energy demands of the fast developing society. However, the efficiency of solar-water-splitting systems is still too low for practical applications, which requires further enhancement via different strategies such as doping, construction of heterojunctions, morphology control, and optimization of the crystal structure. Recently, integration of plasmonic metals to semiconductor photocatalysts has been proved to be an effective way to improve their photocatalytic activities. Thus, in-depth understanding of the enhancement mechanisms is of great importance for better utilization of the plasmonic effect. This review describes the relevant mechanisms from three aspects, including: i) light absorption and scattering; ii) hot-electron injection and iii) plasmon-induced resonance energy transfer (PIRET). Perspectives are also proposed to trigger further innovative thinking on plasmonic-enhanced solar water splitting., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This paper describes a strategy for producing hydrogen via steam reforming of ethylene glycol over supported nickel catalysts. Nickel plays a crucial role in conversion of ethylene glycol and production of hydrogen, while oxide supports affect product distribution of carbonaceous species. A plausible reaction pathway is proposed based on our results and the literature.

This paper describes the utilization of skeletal Ni-based catalysts for steam reforming of ethanol to produce CO-free hydrogen, which could be superior in the application of fuel cells. Assistant metals play different roles in the reaction; Pt and Cu suppress the methanation and enhance H(2) production, while Co promotes the methanation.

The search for efficient nontoxic catalysts able to perform industrial hydrogenations is a topic of interest, with relevance to many catalytic processes. Herein, we describe a mechanistic phenomenon for the activation and spillover of hydrogen for remarkable selectivity in the semi‐hydrogenation of acetylene over sub‐1 nm Pd nanoclusters confined within sodalite (SOD) zeolite (Pd@SOD). Specifically, hydrogen is dissociated on the Pd nanoclusters to form hydrogen species (i.e., hydrogen atoms and hydroxyl groups) that spill over the SOD surfaces. The design and utilization of the small‐pore zeolite SOD (six‐membered rings with 0.28×0.28 nm channels) is crucial as it only allows H2 diffusion into the channels to reach the encapsulated Pd nanoclusters and thus avoids over‐hydrogenation to form ethane. Pd@SOD exhibits an ethylene selectivity of over 94.5 %, while that of conventional Pd/SOD is approximately 21.5 %. [ABSTRACT FROM AUTHOR]

A graphene‐wrapped polyaniline nanoparticles film embedded in carbon cloth (CC/PANI/G) was fabricated and used as a 3D anodic electrocatalyst for oxidation of toluene methyl C−H groups. The methyl C−H bonds can be oxidized effectively at the CC/PANI/G anode with 99.9 % toluene conversion at a low applied voltage of only 1.0 V, which implies low energy input. Importantly, 86.6 % of toluene methyl C−H groups were converted to benzoyl groups (C=O), and hydrogen was produced efficiently at the cathode. The electrocatalytic efficiency at the CC/PANI/G anode was higher at lower voltage (1.0 V) than at higher voltage (1.5 V), and more hydrogen was produced at the corresponding cathode. The synergistic effect between the dynamic redox chemistry of nanoPANI and the excellent conductivity and anticorrosive action of graphene determined the high electrocatalytic efficiency of the oxidation of toluene methyl C−H groups at the CC/PANI/G anode. Owing to the chemical bonding between graphene and PANI, the anticorrosive CC/PANI/G anodic electrocatalyst was durable and effective for oxidation of toluene methyl C−H groups in acidic environment. This approach provides advanced electrode materials for transforming stable chemical bonds (C−H) into useful functional groups (C=O), which will be beneficial for the synthesis of organic intermediates with coupled hydrogen production. [ABSTRACT FROM AUTHOR]

Solar water splitting provides a clean and renewable approach to produce hydrogen energy. In recent years, single-crystal semiconductors such as Si and InP with narrow band gaps have demonstrated excellent performance to drive the half reactions of water splitting through visible light due to their suitable band gaps and low bulk recombination. This Minireview describes recent research advances that successfully overcome the primary obstacles in using these semiconductors as photoelectrodes, including photocorrosion, sluggish reaction kinetics, low photovoltage, and unfavorable planar substrate surface. Surface modification strategies, such as surface protection, cocatalyst loading, surface energetics tuning, and surface texturization are highlighted as the solutions. [ABSTRACT FROM AUTHOR]

Narrow‐band‐gap single‐crystal semiconductors have been considered inappropriate for solar water splitting largely because of the photocorrosion issue. However, several exciting breakthroughs have shown that the instability and other drawbacks of these materials can be overcome. In their Minireview on page 10718 ff., T. Wang and J. Gong describe recent research advances and highlight the most important approaches to using these semiconductors as efficient photoelectrodes. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nanotubes (CNTs) decorated by a high density of carbon nanoparticles of turbostratic graphene stacks have been fabricated by low energy hydrocarbon ion deposition at 700°C. Transmission and scanning electron microscopy show that the carbon particles of turbostratic graphene stacks extend from the nanotube surface. The diameter of CNTs decreases with the increasing percentage of hydrogen in the gas phase. Raman spectroscopy indicates that the formation of carbon nanoparticles of turbostratic graphene stacks results from the high temperature used in the experiment. Meanwhile, Raman spectroscopy and high resolution transmission electron microscopy indicate that the carbon nanoparticle degree of crystallinity is lower with increasing hydrogen content in the gas phase due to the etching effect of hydrogen ions. [Copyright &y& Elsevier]

The modulation of oxygen species is an effective strategy for selective H 2 production with relevant chemical looping processes. This paper describes the promoted oxygen release from CuO-CeO 2 redox catalysts for selective H 2 production in chemical looping oxidative steam reforming of methanol (CL-OSRM). Despite the complete oxidation of methanol from CuO, the excess H 2 production of CL-OSRM with respect to methanol steam reforming (MSR) increases linearly with the amount of active oxygen in CeO 2 induced by the copper-ceria interaction. In situ spectroscopic characterizations and mechanistic study demonstrate that copper-ceria interfacial sites induce oxygen release from CeO 2 to facilitate the partial oxidation of methoxy to formate species, which promotes the H 2 production rate. This study provides an instructive strategy for the construction of redox catalysts for selective H 2 production with chemical looping processes. [Display omitted] • An interfacial engineering strategy for selective hydrogen production is proposed. • The copper-ceria interaction activates the ceria oxygen species. • Interfacial oxygen species facilitate the partial oxidation of methoxy to formate species. • Stable performance and reversible structure can be maintained in redox cycles. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis of CeO 2 -promoted Ni/SBA-15 catalysts (denoted as CeNi/SBA-15) via a surfactant-assisted iso-volumetric impregnation method and their application in ethanol steam reforming. Various techniques including N 2 adsorption–desorption, X-ray diffraction, H 2 temperature-programmed reduction, temperature-programmed oxidation, transmission electron microscopy and thermogravimetric analysis were employed to characterize the prepared and spent catalysts. The results showed that the incorporation of CeO 2 could effectively control the particle size of Ni via strong metal-support interaction and promote the homogeneous distribution of Ni and Ce to achieve large Ni–CeO 2 interface. Consequently, the CeNi/SBA-15 catalysts exhibited superior activity with respect to the reference Ni/SBA-15 catalyst without ceria addition. The effect of ceria loading on the properties of the catalysts was also investigated, and the catalyst with Ce/Ni atomic ratio of 1 was the optimized composition owing to its strong metal-support interaction and high nickel active surface area. The ceria-promoted catalysts showed enhanced long-term stability in ethanol steam reforming. The strong interaction between Ni and CeO 2 , as well as the confinement of SBA-15 support restricted the nickel particle growth under harsh reaction conditions. Additionally, the ceria promoter contributed to suppressing coke deposition effectively, which led to the enhanced coking-resistance as observed on CeNi/SBA-15 catalysts. [ABSTRACT FROM AUTHOR]

Highlights: [•] La1–x Ca x NiO3 perovskite-type oxides were investigated in glycerol steam reforming. [•] The perovskite structure facilitates the uniform distribution of the containing elements. [•] The partial substitution of La by Ca significantly affected the surface properties of La1–x Ca x NiO3. [•] Nickel dispersion and metal-support interaction were critical to the catalytic performance. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes a study regarding the effect of Ni addition to NixMg1−xO solid solutions on the catalytic performances of ethanol steam reforming for hydrogen production. Nickel nanoparticles supported on NixMg1−xO demonstrated higher conversion of ethanol and yields of hydrogen than the bare support. We correlated the improved performances of Ni-based catalysts with the reducibility of nickel species. The addition of Ni to the solid solution support produced more easily reducible surface nickel species. Higher content of bulk nickel species in the support could inhibit the surface nickel species from diffusing into the bulk, leading to more surface nickel species that is easily reducible to its active form. [Copyright &y& Elsevier]

Abstract: In this investigation, diamond thin films with grain size ranging from 50 nm to 1 µm deposited using hot filament chemical vapor deposition (HFCVD) have been analyzed by elastic recoil detection analysis (ERDA) for determining hydrogen concentration. Hydrogen concentration in diamond thin films increases with decreasing grain size. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) results showed that part of this hydrogen is bonded to carbon forming C–H bonding. Raman spectra also indicated the increase of non diamond phase with the decrease in crystallite size. Incorporation of hydrogen in the samples and increase of hydrogen content in nanocrystalline sample are discussed. Large separation between filament and substrate used for the synthesis of nanocrystalline film helped to understand the large incorporation of hydrogen in nanocrystalline diamond films during growth. The study addresses the hydrogen trapping in different samples and higher hydrogen concentration in nanocrystallites by considering the synthesis conditions, growth mechanisms for different grain sized diamond films and from the quality of CVD diamond films. [Copyright &y& Elsevier]