• Energy Research

Lignin is a renewable carbon resource to produce arenes due to its abundant aromatic structures. For the liquid-phase hydrodeoxygenation (HDO) based on metallic catalysts, the preservation of aromatic rings in lignin or its derivatives remains a challenge. Herein, we synthesized Mn-doped Cu/Al2O3 catalysts from layered double hydroxides (LDHs) for liquid-phase HDO of lignin-derived anisole. Mn doping significantly enhanced the selective deoxygenation of anisole to arenes and inhibited the saturated hydrogenation on Cu/Al2O3. With Mn doping increasing, the surface of Cu particles was modified with MnOx along with enhanced generation of oxygen vacancies (Ov). The evolution of active sites structure led to a controllable adsorption geometry of anisole, which was beneficial for increasing arenes selectivity. As a result, the arenes selectivity obtained on 4Cu/8Mn4AlOx was increased to be more than 6 folds of that value on 4Cu/4Al2O3 over the synergistic sites between metal Cu and Ov generated on MnOx.

Abstract The attrition behavior of CaO-based adsorbent particles was systematically studied in a laboratory-scale fluidized device. Five operational and design parameters were investigated in terms of attrition. Fine powder production, attrition rate and particle size statistics were experimentally analyzed to explore the attrition characteristics of the particles. The results revealed that longer time aggravated the breakage, and larger particles possessed the better attrition resistance. Higher gas velocity promoted the attrition rate. Larger orifice number and orifice diameter reduced the degree of attrition. Linear fitting was used to analyze the relation between the mass of fine powder and other parameters. A mathematical model- R = 0.67 × 10 9 ⋅ D − 0.848 ⋅ U 3.136 ⋅ n or − 0.950 ⋅ d or − 1.196 was established on the basis of experimental results to combine the effects of the various parameters. The model could be used to describe, simulate and predict the fluidized attrition phenomenon of particles.

Carbon dioxide (CO2) is a major greenhouse gas and makes a significant contribution to global warming and climate change. Thus CO2 capture and storage (CCS) have attracted worldwide interest from both fundamental and practical research communities. Alkali-metal-based oxides such as alkali-metal oxides, binary oxides, and hydrotalcite-like compounds are promising adsorbents for CO2 capture because of their relatively high adsorption capacity, low cost, and wide availability. They can also be applied to the adsorption-enhanced reactions involving CO2. The microstructures (e.g., surface area, porosity, particle size, and dispersion) of these oxides determine the CO2 adsorption capacity and multicycle stability. This perspective critically assesses and gives an overview of recent developments in the synthesized method, adsorption mechanism, operational conditions, stability, and regenerability of a variety of oxides. Both pros and cons of these oxides are also discussed. Insights are provided into several effective procedures regarding microstructural control of alkali-metal-based oxides, including preparation optimization, modification, stream hydration, etc.

In this work, thermodynamics was applied to investigate the glycerol autothermal reforming to generate hydrogen for fuel cell application. Equilibrium calculations employing the Gibbs free energy minimization were performed in a wide range of temperature (700–1000 K), steam to glycerol ratio (1–12) and oxygen to glycerol ratio (0.0–3.0). Results show that the most favorable conditions for hydrogen production are achieved with the temperatures, steam to glycerol ratios and oxygen to glycerol ratios of 900–1000 K, 9–12 and 0.0–0.4, respectively. Further, it is demonstrated that thermoneutral conditions (steam to glycerol ratio 9–12) can be obtained at oxygen to glycerol ratios of around 0.36 (at 900 K) and 0.38–0.39 (at 1000 K). Under these thermoneutral conditions, the maximum number of moles of hydrogen produced are 5.62 (900 K) and 5.43 (1000 K) with a steam to glycerol ratio of 12. Also, it should be noted that methane and carbon formation can be effectively eliminated.

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 Fe5C2 nanocatalyst exhibits excellent catalytic activity with a significantly high selectivity of 89.6% to ethanol in gas-phase hydrogenation of dimethyl oxalate.

AbstractA facile one‐pot hydrothermal method is developed to synthesize a series of carbon nanotubes–manganese oxide nanocomposites (CNTs–MnOx) with different morphologies and Mn valence states. These nanocomposite materials are then utilized as catalyst supports in iron‐based Fischer–Tropsch synthesis (FTS) for the production of liquid fuels. Experimental results indicate that Fe/CNTs‐K‐190 (iron catalyst supported on the CNTs treated with KMnO4 at 190 °C) and Fe/CNTs‐KU‐190 (iron catalyst supported on the CNTs treated with KMnO4 and urea at 190 °C) display higher FTS activity than the Fe/CNTs‐K‐110 (iron catalyst supported on CNTs treated with KMnO4 at 110 °C) and Fe/CNTs‐KU‐110 (iron catalyst supported on CNTs treated with KMnO4 and urea at 110 °C). This might be due to the weak metal–support interaction and high MnO content, and the poorer stability than Fe/CNTs‐K‐110 and Fe/CNTs‐KU‐110 catalysts with nanosheet morphology might be related to the structural collapse of the nanocubes or nanorods due to MnO evolution during the FTS process. The CNTs–MnOx nanocomposite‐supported iron FTS catalysts in particular display unparalleled high C5+ selectivity (over 90 %) and very low CH4 selectivity (below 4.6 %). The unique CNTs–MnOx nanocomposites may open a new window for the understanding, design, synthesis, and optimization of iron catalysts toward high‐efficiency transport fuel production.