## 留言板

Nitrogen-doped carbons (Nano-NC) are often employed as functional supports for boosting oxygen reduction reaction (ORR) over Pt-based catalysts, however, the mechanism of N doping on the adsorption and activation of molecular oxygen on Pt active sites is still not clear. Herein, Nano-NCs as the supports were prepared by a facile NH3 antipyretic method, which allowed to tune the kinds of nitrogen species in carbon matrix and their contents by adjusting the NH3 antipyretic temperatures.With such an exquisite control, the Pt nanoparticles loaded on the as-obtained Nano-NC showed an optimal Pt particle size (2.10 nm), a higher content of Pt0, a large electrochemically active surface area, and fast electron transport ability. As a consequence, the Pt/Nano-NC-800 catalyst with the optimal N-doping showed an outstanding ORR performance with half-wave potential of 0.80 V vs. RHE, limit diffusion current of 5.37 mA/cm2 and improved methanol/CO anti-poisoning, which is superior to the commercial Pt/C catalyst (20 wt%, JM), and most of previously reported Pt-based catalysts. This work may pave a way for the design of the advanced supports for Pt-based catalysts for the ORR applications.

NaHCO3是一种高效的烟气脱酸剂，但脱酸过程中NaHCO3对于SeO2的吸附效果及机理尚不明确。本文通过吸附实验探究了140−220 ℃下NaHCO3对SeO2的吸附性能，通过一系列表征解析了吸附后的样品中硒的总量、价态和形态，结合密度泛函理论计算，探讨了NaHCO3对SeO2的吸附机理。结果表明，NaHCO3对SeO2的吸附性能随温度的升高而增加，在吸附过程中同时发生NaHCO3向Na2CO3的分解反应，分解后产生的Na2CO3吸附活性更强。SeO2吸附过程属于SeO2中Se原子与Na2CO3表面O原子成键的化学吸附，吸附产物以亚硒酸盐为主。

Oxidation treated carbon materials for exploiting highly efficient and stable loaded catalysts have been proven to be valid. In this work, the surfaces of carbon aerogels (CA) were functionalized with different oxidizing agents, i.e., H2O2 and HNO3. A series of Ru-supported catalysts on carbon aerogels (CA) with/without functionalized were prepared by the impregnation strategy. The impact of oxidation treatment on the texture features of carbon aerogels, the types and contents of formed surface oxygen-containing functional groups, the metal-support interactions and the Fischer-Tropsch synthesis reaction performances of i the catalysts were systematically investigated. Our results showed that Ru/CA catalyst without oxidation treatment displayed the highest initial activity but the poor stability, while the Ru/CA−H2O2 catalyst exhibited excellent activity and C5+ selectivity. The oxidation treatment increased the carbon aerogels defects, thereby broadening the specific surface area. The increased content of oxygen-containing functional groups on the surface enhanced the interaction between the support and Ru nanoparticles and improved the stability of the catalyst. Nevertheless, the excessive oxygen-containing functional groups on the surface decreased the activity and the C5+ selectivity of carbon aerogels-loaded Ru catalysts.

Herein, SiO2 supported metallic Ni (Ni/SiO2) and bimetallic Ni-Zn (NixZn/SiO2) (x represents the Ni/Zn atomic ratio) catalysts were prepared by the incipient wetness impregnation method and their activities were tested in vapor phase hydrodeoxygenation (HDO) of anisole under 0.1 MPa. It has been found The characterization results show that the Ni-Zn alloy forms in NixZn/SiO2 after reduction at 550 °C, and the a suitable Ni/Zn atomic ratio (30) leads to smaller metal crystallites alloy particle size and consequently more H2 adsorption amount than others. In the HDO reaction, the formation of Ni-Zn alloy facilitates the direct deoxygenation pathway and suppresses CO methanation and C−C bond hydrogenolysis, which is ascribed to the isolation effect of the Ni atoms by the oxophilic Zn ones. Ni30Zn/SiO2 gives not only higher anisole conversion but also higher selectivity to benzene than Ni/SiO2. Therefore, the introduction of a suitable amount of oxophilic Zn in Ni/SiO2 promotes the HDO of anisole to benzene. Finally, we suggest propose that the Ni30Zn/SiO2 deactivation is related to the surface oxidation of Ni-Zn alloy and carbonaceous deposit carbon deposition on the catalyst surface.

Co/HZSM-5 catalyst was fabricated for catalytic dehydrogenation of propane to propylene, which was pretreated to allow the reaction to react at low temperatures. A response surface approach was employed to examine the effect of process conditions on the reaction. The morphological and oxidative performance of Co/HZSM-5 was characterized by XRD, XPS, SEM, NH3-TPD, H2-TPR, and nitrogen physical absorption-desorption. Besides, the in-situ catalyst performance was evaluated by a fixed-bed reactor. Combining the actual experimental conditions, the optimal process conditions parameters obtained by the response surface method were as follows: a reaction temperature of 461 °C, a Co loading of 2.4 wt.%, and a GHSV of 4300 h−1. At this point, the propylene yield reached 27.7% and the corresponding propylene selectivity was up to 93.8 %.

Oxidation treated carbon materials for the exploitation of efficient and stable loaded catalysts have been proven to be valid. The surfaces of carbon aerogels (CA) were functionalized with different oxidizing agents, H2O2 and HNO3. A series of Ru-supported catalysts were prepared by impregnation on carbon aerogel (CA) with/without functionalized. The impact of oxidation treatment on the texture features of carbon aerogels, the types and contents of formed surface oxygen-containing functional groups, the metal-support interactions and the Fischer-Tropsch synthesis reaction performance of the catalysts were systematically investigated using XRD, Raman spectra, N2-physisorption, H2-TPR, FTIR and XPS. The experimental results showed that Ru/CA catalyst displayed the highest initial activity but poor stability. In contrast, the Ru/CA-H2O2 catalyst exhibited excellent activity and C5+ selectivity. Characterization results demonstrated that the oxidation treatment increased the carbon aerogels defects, thereby enhanced the specific surface area. The increased content of oxygen-containing functional groups on the surface enhanced the interaction between the support and Ru nanoparticles and improved the stability of the catalyst. Nevertheless, the excessive oxygen-containing functional groups on the surface decrease the activity and C5+ selectivity of carbon aerogels-loaded Ru catalysts.

CO2电催化还原合成高附加值燃料为CO2转化利用提供了一条可持续发展的途径。然而，开发具有优异催化活性和产物选择性的电催化剂仍面临巨大的挑战。本文制备了铜改性黄铁矿催化剂CuxFe1-xS2，采用XRD、XPS、SEM等表征分析方法研究了催化剂的物理化学性质，并研究了催化剂的CO2电催化还原活性和产物选择性。实验结果表明，Cu掺杂可以调控催化剂纳米片的尺寸，同时可以抑制FeS2在空气中的氧化。Cu0.33Fe0.67S2比FeS2表现出更好的催化反应活性，在−1.5−−1.6 V vs. RHE范围内，CO2电催化还原的含碳产物法拉第效率为50.8%，电流密度为23.8 mA·cm−2。相比于FeS2催化剂，电流密度提高了71.2%。Cu0.09Fe0.91S2在−1.3 V vs. RHE下生成C3H6的法拉第效率为21.8%，显著高于目前文献中已报道的数值。因此，CuxFe1-xS2是一种比较有前景的CO2电催化还原催化剂。

To address the slagging problem during coal entrained-flow bed (EFB) gasification, the influences of textile dyeing sludge (TDS) addition on the fusing characteristics of high ash fusion temperature (AFT) coal were explored under a reducing atmosphere. And the change mechanisms were investigated by X-ray diffraction, Fourier Transform Infrared Spectroscopy (FT-IR) and FactSage calculation. The results showed that the flow temperature of high ash fusion temperature (AFT) coal decreased below 1380 °C when the TDS addition reached 20%−25%, which met the requirements of liquid-slag removal for EFB gasification. With the content of TDS increasing, the formations of low-melting minerals (e.g., hercyniye, anorthite, and albite) decreased AFT. The bridging oxygen bonds of the network structure were destroyed by metal ions (e.g., Fe2+, Ca2+, Na+), formation of much non-bridged oxygen (NBO) bonds relaxed the silicate network, thus decreasing the AFT. The formations of NBO bonds were confirmed by gradual decreases in the peak strengths of Si−O−Si and Si−O−Al bonds and intensified the vibration of Fe−O and Si−O−M ( M: Ca2+ or Na+) bonds. FactSage calculation results were in good agreement with the experimental ash fusion behavior.

Metal oxide - zeolite (OX-ZEO) bifunctional catalysts have been shown to have excellent aromatic selectivity and catalytic stability in syngas conversion; however, low CO conversion hinders their further development. In this paper, a series of In-ZrO2 bi-metallic oxides with In/Zr molar ratio ranging of 1/100~1/1 were prepared. After thoroughly investigated by X-ray diffraction, transmission electron microscopy, N2 sorption, pyridine-adsorbed infrared spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance and temperature programmed desorption technologies, we found that introduction of indium has significantly influence on the catalytic performance due to the variation of sample’s physicochemical properties. Indium species was benefit to the dissociation of H2 that promotes CO activation. Nevertheless, it also induced the formation of more CH4. In-ZrO2 oxide with In/Zr ratio of 1/50 showed CO conversion of 18.2% with the selectivity of oxygenates of 86.4%. After combined with H-ZSM-5, In/Zr=1/50&H-ZSM-5 gave CO conversion of 46.5% with ${\rm{C}}_5^ +$ selectivity of 62.6% and the aromatic selectivity in ${\rm{C}}_5^ +$ reached 93.4%. However, the catalytic stability of this bifunctional catalyst was gradually decreased due to the aggregation of indium atoms.

The co-combustion of the low-rank coal with coal derived semi-coke is of great significance to solve the urgent problem of excessively produced semi-coke in China. In this research, the oxy-fuel co-combustion characteristics of Zhundong sub-bituminous coal with bituminous coal derived semi-coke are systematically investigated using thermogravimetric analysis. Compared with air combustion, oxy-fuel atmosphere increased the ignition and burnout temperature by 10 ℃ and 40 ℃, respectively. Increasing the oxygen concentration to 30% strongly compensated for the slight reduction of the combustion parameters under oxy-fuel condition and much better co-combustion performance was obtained. Three iso-conversional methods, namely, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Starink, were applied to estimate the activation energy, which can be divided into two stages during the co-combustion process. The average activation energy of sub-bituminous coal, the blend and semi-coke were 49.31 kg/mol−1 50.82 kg/mol−1 and 59.00 kg/mol−1, respectively. Further, the pre-exponential factor and thermodynamic parameters of the enthalpy change, Gibbs free energy change and entropy change were calculated. Interaction indices were innovatively used for both kinetic-thermodynamic parameters and DTG values. An obvious interaction can be observed during the co-combustion process. The kinetic and thermodynamic results demonstrated that the 30% semi-coke ratio was beneficial to co-combustion. Meanwhile, X-ray fluorescence (XRF) and ash fusion analyses proved that the slagging tendency of sub-bituminous coal ash reduced by blending of semi-coke.

To explore the catalytic performance of three perovskites (LaBO3--LaCoO3, LaFeO3, LaNiO3), the experimental characterization methods (GC−MS, FT−IR, elemental analysis) and DFT calculation were combined for researching liquefaction of lignin. The effects of time, temperature, catalyst dosage and B cation on the conversion rate, bio-oil yield and bio-oil component distribution were investigated. The results showed that all the three catalysts could promoted the liquefaction of lignin to produce aromatic compounds. Among them, LaCoO3 had the greatest promoting on bio-oil yield, and the highest bio-oil yield of 67.20wt% was obtained at 180 °C for 60 min over 5wt% LaCoO3, followed by LaNiO3 and LaFeO3. The relative content of mono-aromatic compounds reached 89.59% under LaCoO3. Mechanism studies suggested that the adsorption of oxygen atoms on the surface of LaBO3 crystal with lignin reduced the dissociation energy of bonds of lignin. Moreover, LaCoO3 had moderate redox capacity, largest adsorption energy, loose and porous morphology, which could effectively promoted the fracture of C−C and CAr−OCH3 of lignin, so that achieved macromolecular depolymerization and demethoxylation reaction to produce high value-added compounds such as phenol.