Single-pass transformation of syngas into ethanol with high selectivity by triple tandem catalysis

乙醇既可作为替代燃料或优质汽油添加剂亦是重要基础化学品，同时也是一种理想的氢载体。乙醇需求量近年增长迅速，我国需求缺口巨大，当前合成气合成乙醇有三种方法，其中直接法因在同一催化剂上存在多种反应通道，导致产物选择性不超过60%。另一方面，多步法路线虽然较为成熟，但因反应和分离/纯化步骤多，存在成本贵、能耗高等问题。发展合成气直接制乙醇的新方法和新路线具有重大意义。王野课题组在C1化学领域率先提出以接力催化控制反应选择性的新方法，并在合成气高选择性制备液体燃料、低碳烯烃和芳烃等方面取得成功。该工作是在王野教授、张庆红教授共同指导下完成的。醇醚酯化工清洁生产国家工程实验室高工康金灿、2018级博士生何顺和2017级博士生周伟为论文共同第一作者。陈明树教授课题组在原位红外、准原位XPS等表征中给予了支持，南京大学彭路明教授课题组在固体核磁表征方面提供了帮助。Synthesis of ethanol from non-petroleum carbon resources via syngas (a mixture of H2 and CO) is an important but challenging research target. The current conversion of syngas to ethanol suffers from low selectivity or multiple processes with high energy consumption. Here, we report a high-selective conversion of syngas into ethanol by a triple tandem catalysis. An efficient trifunctional tandem system composed of potassium-modified ZnO–ZrO2, modified zeolite mordenite and Pt–Sn/SiC working compatibly in syngas stream in one reactor can afford ethanol with a selectivity of 90%. We demonstrate that the K+–ZnO–ZrO2 catalyses syngas conversion to methanol and the mordenite with eight-membered ring channels functions for methanol carbonylation to acetic acid, which is then hydrogenated to ethanol over the Pt–Sn/SiC catalyst. The present work offers an effective methodology leading to high selective conversion by decoupling a single-catalyst-based complicated and uncontrollable reaction into well-controlled multi-steps in tandem in one reactor.This work was supported by the National Key Research and Development Program of the Ministry of Science and Technology of China (No. 2017YFB0602201) and the National Natural Science Foundation of China (Nos. 91945301, 91545203, 21972116, 21433008, 21872112, 21673188 and 21690082). We acknowledge Prof. L. Peng and Y. Wen (Nanjing University, China) for performing NMR characterizations.该研究得到科技部重点研发计划(2017YFB0602201)和国家自然科学基金重大研究计划(91945301、91545203)等项目的资助

Facile Fabrication of Dual Functional Graphene Oxide Microcapsules Carrying Corrosion Inhibitor and Encapsulating Self-Healing Agent

Dual functional graphene oxide (GO) microcapsules were fabricated through self-assembly in Pickering emulsions, carrying corrosion inhibitor benzotriazole (BTA) on the microcapsule shells and encapsulating a self-healing agent epoxy monomer. The formation of the GO microcapsules was assisted by the interaction between BTA and GO, which provided robust encapsulation for the epoxy monomer. The loading capacity of BTA and epoxy monomer reached 90.5%. The addition of the GO microcapsules simultaneously promoted the corrosion protection and self-healing properties of the waterborne epoxy composite coatings. The healing efficiency of the composite coatings reached over 99.7% when the content of the microcapsules was 10 wt%. Meanwhile, the corrosion current density of the intact coatings was decreased for around 50 times

Photoinduced Radical Desulfurative C(sp³)–C(sp²) Coupling via Electron Donor–Acceptor Complexes

Herein, we disclose a radical desulfurative C–C coupling protocol for the synthesis of 4-alkylpyridines. A variety of substituents on both benzyl thiols and 4-cyanopyridines are tolerated. The reaction is carried out under mild and photocatalyst- and transition-metal-free conditions. Preliminary mechanistic studies show that an electron donor–acceptor complex is formed between benzyl thiols and 4-cyanopyridines under alkaline conditions. Then, a variety of 1°, 2°, and 3° C(sp3)-centered radicals was formed by cleavage of the C–S bond, and the 4-alkylpyridines were achieved through a radical–radical coupling with the pyridyl radical anion

Recent progress on MOF‐derived carbon materials for energy storage

Abstract Metal‐organic frameworks (MOFs) are of quite a significance in the field of inorganic‐organic hybrid crystals. Especially, MOFs have attracted increasing attention in recent years due to their large specific surface area, desirable electrical conductivity, controllable porosity, tunable geometric structure, and excellent thermal/chemical stability. Some recent studies have shown that carbon materials prepared by MOFs as precursors can retain the privileged structure of MOFs, such as large specific surface area and porous structure and, in contrast, realize in situ doping with heteroatoms (eg, N, S, P, and B). Moreover, by selecting appropriate MOF precursors, the composition and morphology of the carbon products can be easily adjusted. These remarkable structural advantages enable the great potential of MOF‐derived carbon as high‐performance energy materials, which to date have been applied in the fields of energy storage and conversion systems. In this review, we summarize the latest advances in MOF‐derived carbon materials for energy storage applications. We first introduce the compositions, structures, and synthesis methods of MOF‐derived carbon materials, and then discuss their applications and potentials in energy storage systems, including rechargeable lithium/sodium‐ion batteries, lithium‐sulfur batteries, supercapacitors, and so forth, in detail. Finally, we put forward our own perspectives on the future development of MOF‐derived carbon materials

Chromophoric Fingerprinting of Brown Carbon from Residential Biomass Burning

Emissions from residential biomass burning are a significant source of atmospheric brown carbon (BrC). In this study, we used liquid chromatography-photodiode array-high resolution tandem mass spectrometry to investigate the chromophoric fingerprinting of BrC emitted from residential biomass burning. In total, 59 major chromophores were identified, which accounted for 49-85% of the total light absorption of BrC (averaged between 300 and 500 nm) for different samples. These chromophores include furans, lignin pyrolysis products, coumarins, flavonoids, stilbenes, N-containing aromatic compounds, and unsubstituted or oxygenated polycyclic aromatic hydrocarbons, of which some are newly reported as BrC species (e.g., stilbenes and substituted phenyl cyanates). Among the chromophores identified, seven are common to all samples while some are specific to certain biofuel or burning conditions. For instance, 3,3'-dimethoxyquercetin from wheat burning, p-hydroxybenzaldehyde and apigenin from maize smoldering, 4-nitro-2-vinylphenol from maize flaming, and nodakenetin and anthanthrene from wood flaming are specific to the fuel type or burning condition. The identified optical markers will be essential for understanding atmospheric chemical and optical processes of biomass burning BrC in future studies, while the source-specific chromophore profiles developed in this study are a prerequisite for apportioning the biofuel types and burning conditions, which is a key for estimating source-specific radiative forcing

Organosulfates in atmospheric aerosol: synthesis and quantitative analysis of pm<sub>2.5</sub> from xi\u27an, northwestern china

The sources, formation mechanism and amount of organosulfates (OS) in atmospheric aerosol are not yet well understood, partly due to the lack of authentic standards for quantification. In this study, we report an improved robust procedure for the synthesis of organosulfates with different functional groups. Nine authentic organosulfate standards were synthesized and four standards (benzyl sulfate, phenyl sulfate, glycolic acid sulfate, and hydroxyacetone sulfate) were used to quantify their ambient concentrations. The authentic standards and ambient aerosol samples were analyzed using an optimized ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometric method (UPLC-ESI-MS/MS). The recovery ranged from 80.4 to 93.2 %, the limits of detection and limits of quantification obtained were 1.1-16.7 and 3.4-55.6 pg m(-3), respectively. Measurements of ambient aerosol particle samples collected in winter 2013/2014 in urban Xi\u27an, northwestern China, show that glycolic acid sulfate (77.3 +/- 49.2 ng m(-3)) is the most abundant species of the identified organosulfates followed by hydroxyacetone sulfate (1.3 +/- 0.5 ng m(-3)), phenyl sulfate (0.14 +/- 0.09 ng m(-3)), and benzyl sulfate (0.04 +/- 0.01 ng m(-3)). Except for hydroxyacetone sulfate, which seems to form mainly from biogenic emissions in this region, the organosulfates quantified during winter in Xi\u27an show an increasing trend with an increase in the mass concentrations of organic carbon indicating their anthropogenic origin

Water-Insoluble Organics Dominate Brown Carbon in Wintertime Urban Aerosol of China: Chemical Characteristics and Optical Properties

The chromophores responsible for light absorption in atmospheric brown carbon (BrC) are not well characterized, which hinders our understanding of BrC chemistry, the links with optical properties, and accurate model representations of BrC to global climate and atmospheric oxidative capacity. In this study, the light absorption properties and chromophore composition of three BrC fractions of different polarities were characterized for urban aerosol collected in Xi'an and Beijing in winter 2013-2014. These three BrC fractions show large differences in light absorption and chromophore composition, but the chromophores responsible for light absorption are similar in Xi'an and Beijing. Water-insoluble BrC (WI-BrC) fraction dominates the total BrC absorption at 365 nm in both Xi'an (51 +/- 5%) and Beijing (62 +/- 13%), followed by a humic-like fraction (HULIS-BrC) and high-polarity water-soluble BrC. The major chromophores identified in HULIS-BrC are nitrophenols and carbonyl oxygenated polycyclic aromatic hydrocarbons (OPAHs) with 2-3 aromatic rings (in total 18 species), accounting for 10% and 14% of the light absorption of HULIS-BrC at 365 nm in Xi'an and Beijing, respectively. In comparison, the major chromophores identified in WI-BrC are PAHs and OPAHs with 4-6 aromatic rings (in total 16 species), contributing 6% and 8% of the light absorption of WI-BrC at 365 nm in Xi'an and Beijing, respectively