查看更多>>摘要：The bimetallic nickel zinc catalyst (Ni@Zn) with hierarchical morphology has been fabricated successfully by an ultrafast and simple synthesis strategy. Unique hierarchical morphology of the catalyst composes of honeycomb arrays, which are formed by Ni shell/Zn core leaves. This Ni@Zn possesses excellent catalytic activity, stability, and selectivity towards borohydride oxidation reaction (BOR). Moreover, a direct borohydride fuel cell (DBFC) with the Ni@Zn/C anode delivers a peak power density of 180.3 mW cm-2 at 298 K. The outstanding performances originate from the increase of electroactive surface area, enhancement of reactants adsorption, and the inhibition of Ni oxidation, which are attributed to its unique hierarchical structure and the introduction of Zn. This study may provide important inspiration for developing efficient noble-metal-free catalysts for DBFC.
查看更多>>摘要：The existing catalysts for sulfate radical-based advanced oxidation processes (SR-AOPs) are mostly in the powder form. However, the application of powdered catalyst often leads to problems such as increased cost due to difficult recovery. In this study, an in-situ synthesized self-supporting cobalt-doped nickel sulfide nanosheet array on nickel foam (NCS/NF) is proven capable of working as a recyclable and integrated catalyst for perox-ymonosulfate (PMS) activation. This integrated catalyst is more practical in water treatment due to its separable and recyclable properties. In this study, a series of experiments show that the catalytic degradation performance of NCS/NF toward levofloxacin hydrochloride (LFX) could be comparable to most powdered catalysts. The catalytic mechanism analyses show that the incorporated cobalt plays a predominant role in enhancing PMS activation.
查看更多>>摘要：Photocatalytic two-electron oxygen reduction reaction (2e(-)ORR) has been regarded as a promising strategy to solve the disadvantage of Fenton technology (constant addition of H2O2). Herein, a photocatalysis-self-Fenton system was constructed on garland g-C(3)N(4 )with carbon defects (GCN-PSFs) for pollutants degradation. Carbon defects in the obtained GCN not only accelerate charge separation but also improve 2e(- )ORR. As expected, the apparent rate constant for 2,4-DCP degradation by GCN-PSFs enhances to 0.070 min(-1), which is 5.4, 3.3 and 2.6 times as that of BCN, BCN-PSFs and GCN. The capture experiments and electron spin resonance indicate that the high activity is attributed to abundant center dot & nbsp;OH radicals, which are formed from the in-situ produced H2O2. Density functional theory (DFT) calculation confirms that the carbon defects in GCN is favorable for photocatalytic 2e(-) ORR to H2O2. This work provides a new insight for high-efficient degradation of organic pollutants by PSFs.
查看更多>>摘要：The high-efficient and low-cost oxygen electrocatalysts are of significant importance but challenge in energy storage and conversion devices. The oxygen electrocatalysis involves triple-phase interfaces of solid catalyst, liquid electrolyte and gaseous oxygen. The reaction microenvironment in which the ample transmission pathway sufficiently feeds the highly active sites and expulses product rapidly is typically desired. Herein, the reaction interface microenvironment of hollow spherical bimetallic electrocatalyst (CoFe-SNC) is regulated via structural architecture engineering, achieving the ample triple-phase contact points of O-2 (gas), electrolyte (liquid) and electrocatalyst (solid). Sufficient O-2 supply and unimpeded mass transfer afforded by triple-phase interface flourish catalytic efficiency and enhance oxygen electrocatalysis. Simultaneously the incorporation of sulfur dopant improves the intrinsic catalytic activity, giving rise to highly active sites in reaction interface of CoFeSNC. With such well-constructed triple-phase interface microenvironment, the CoFe-SNC shows outstanding oxygen reduction reaction activity (E1/2 = 0.86 V vs RHE) and stability in basic media, and a low charging-discharging voltage gap (1.19 V) with excellent durability is realized in rechargeable Zn-air batteries.
查看更多>>摘要：Layered structural BiOBr with {110} facet exposure is a promising functional material for highly selective adsorption and separation of heavy metal ions in water purification. In this study, the distinct adsorption behaviors of As(III), As(V), and Cr(VI) on {110} facet were theoretically and experimentally investigated. The results suggested that uncharged As(III) was dominantly adsorbed on the [Bi2O2](2+) surface replacing the hydroxyl group, whereas Cr(VI) and As(V) oxyanions preferentially intercalated on {110} facet by exchange with Br- ions between the layers. Moreover, due to interfacial coupling configuration ([BiO-CrO4-OBi]-O-As(OH)(2)) between the surface and interlayer on {110} facet, the synergic removal of Cr(VI) and As(III) could be accelerated under photoexcitation to induce a direct electron transfer from surface AsIII to interlayer CrVI, forming AsV and CrIII. Subsequently, approximately 69.3% of Cr(III) and 98.6% of As(V) were readily desorbed in acidic conditions and a high concentration of Br- solution, respectively, to achieve simultaneous detoxification and selective separation.
查看更多>>摘要：Steering the electronic structure of a catalyst has been considered as an effective way to boost the electrocatalytic activity of hydrogen evolution reaction (HER). Herein, a core-shell architecture comprising a Ru nanoparticle (NP) encapsulated into an oxyfullerene-like carbon cage decorated with single-atomic RuNx species anchored on nitrogen-doped carbon substrate (RuNP@RuNx-OFC/NC) was constructed. Benefiting from the efficient electronic communication between Ru NP and atomically-distributed Ru site on the carbon cage, the RuNP@RuNx-OFC/NC exhibited outstanding electrocatalytic performance for HER both in acid and alkaline. Experimental and theoretical results demonstrated that the charge transfer from Ru NP to single-atomic Ru could steer the electronic density of Ru sites and thus facilitate the adsorption of hydrogen and dissociation of water. Resultantly, such charge electronic communication effectively reduced the Gibbs free energy, leading to the improved HER activity. The present work would promote the design and construction of efficient electrocatalysts for energy conversion and storage.
Ji, XiaolinLiu, YanshuoLiu, JiameiZhang, Junshe...
9页
查看更多>>摘要：Selective hydrogen combustion in-situ can break the thermodynamic limit of methane dehydroaromatization, which enhances the yield of aromatic hydrocarbons at a given operating temperature. In this study, sodium tungstate (Na2WO4) was loaded on manganese ore by incipient wetness impregnation, which improved the selectivity of hydrogen combustion dramatically. The selectivity of hydrogen combustion (the percentage of lattice oxygen species involved in hydrogen combustion) is 86% and 53% for Na2WO4-tuned and pristine manganese ore at 750 degrees C, respectively. Introducing Na2WO4 causes a decrease in both the Mn(IV) fraction and oxygen vacancies in the surface layer as well as changes the crystal structure and the morphology of Mn ore. They are attributed to W ions substituting Mn ions, which makes benzene becomes more difficult to be activated compared with hydrogen at the metal oxide/Na2WO4 interface.
Kondaveeti, SanathPark, Gi DaeShanmugam, RamasamyPagolu, Raviteja...
15页
查看更多>>摘要：A new enzymatic biofuel cell (EBFC) is developed using conductive metal alloy nanoparticles with carbon cloth (CC) as an immobilization support for ethanol dehydrogenase (EtDH) and formolase (FLS). Ethanol (EtOH) dehydrogenation to acetaldehyde via direct electron transfer (DET) is pursued as the first step, followed by the condensation of acetaldehyde to acetoin. Metals are deposited onto novel three-dimensional jellyfish (JF)-shaped nanoparticles (SiO2-NCNT-CoFe2), where NCNT denotes "N-doped carbon nanotube ". The fabricated JF-me-tal-CC-EtDH bioelectrodes exhibit a variation in power generation with varying metals, with a value 37.6-fold higher than that of previously reported EBFC operations with DET for EtOH oxidation. The highest acetoin content is also found in JF-Os-CC-EtDH-FLS, attributable to faster electron uptake by the bioelectrode. First-principles calculations suggest that the d-state delocalization of metal-loaded JF particles is the cause of the enhanced catalytic activity, and it can be utilized in designing electrocatalysts.
查看更多>>摘要：Electrochemical production of commodity chemicals via CO2-H2O co-electrolysis using solid oxide electrolysis cells presents a promising cost-effective energy-storage approach. Here, we harness the unique property of protonic ceramic electrolysis cells (PCEC) and demonstrate direct electrochemical production of CH4 from CO2-H2O in a PCEC unit-cell stack. An exceptional CH4-yield ratio of 34.6% from only CO2-H2O reactants and greater than 70% with exhaust H-2 recycle were achieved under an electrolysis current of -1 A cm(-2) at 450 degrees C. Additionally, the electrochemical co-conversion of CO2-H2O offered a higher CH4-yield ratio compared to the thermochemical conversion of CO2-H-2 under certain operating conditions, indicating possible electrochemical promotion of catalytic CO2 methanation. Techno-economic analyses were conducted to reveal potential operating conditions that yield a promising levelized cost of fuel production. The demonstrated good performance of the unit-cell stack shows promising scalability of PCECs for practical application from a system-level viewpoint.
Zhu, ChengGutierrez, Oliver Y.Santosa, Daniel M.Flake, Matthew...
11页
查看更多>>摘要：The rational selection of catalysts and process parameters for co-processing biomass-and waste-derived biocrudes with petroleum streams requires detailed reaction networks and kinetics of the conversion of heteroatomcontaining compounds existed in both kinds of feedstocks. We provide the kinetics and reaction networks for the hydrotreating of N,N-diethyldodecanamide and N-methyldodecanamide, model compounds of major components in bio-crudes from hydrothermal liquefaction of wet waste. Their conversion undergoes via two pathways over sulfided NiMo/Al2O3 catalyst: deoxygenation followed by denitrogenation of the amine intermediate (DO pathway), and denitrogenation followed by deoxygenation of the alkanol intermediate (DN pathway)-with the DO pathway dominant over the DN pathway. H2S inhibits the deoxygenation step and promotes the denitrogenation step in the DO pathway. The amine intermediate inhibits the amide conversion, with weaker effects on the conversion of secondary amide than on the tertiary amide. The kinetics of hydrotreating of several model compounds representing the main species during co-processing indicate that the removal of nitrogenous species, which are in large quantities and of varying structures, remains the main challenge (compared with S-and O removal) for co-processing.
NSTL
Elsevier