Air pollution from particulate matter produced by incomplete combustion of diesel fuel has become a serious environmental pollution problem,which can be addressed by catalytic combustion.In this work,a series of K-mod...Air pollution from particulate matter produced by incomplete combustion of diesel fuel has become a serious environmental pollution problem,which can be addressed by catalytic combustion.In this work,a series of K-modified MnO_(δ)catalysts with different microstructures were synthesized by the hydrothermal method,the relationship between structure of the catalysts and their catalytic performance for soot combustion was studied by characterization techniques and density functional theory(DFT)calculations.Results showed that the prepared catalysts had good catalytic performance for soot combustion and could completely oxidize soot at temperatures below 400℃.The cryptomelane-type K_(2−x)Mn_(8)O_(16)(K-OMS-2)with tunnel structure had excellent NO oxidation capacity and abundance of Mn^(4+)ions(Mn^(4+)/Mn^(3+)=1.24)with good redox ability,it demonstrated better soot combustion performance than layered birnessite-type K_(2)Mn_(4)O_(8)(K-OL-1).The T_(10),T_(50),T_(90)temperatures of KOMS-2 were 269,314,346℃,respectively.The K-OMS-2 catalyst also showed excellent stability after five catalytic cycles,with T_(10),T_(50),T_(90)values holding in the ranges of 270±2,316±2,348±3℃,respectively.展开更多
Nd-Co 3O 4 catalysts were prepared by hydrothermal and co-precipitation methods to catalyze the decomposition of N 2O. The catalysts prepared by hydrothermal method showed higher activity. Among the hydrothermal Nd-Co...Nd-Co 3O 4 catalysts were prepared by hydrothermal and co-precipitation methods to catalyze the decomposition of N 2O. The catalysts prepared by hydrothermal method showed higher activity. Among the hydrothermal Nd-Co 3O 4 catalysts, the catalyst with Nd/Co molar ratio of 0.01 had higher activity. 0.01Nd-Co 3O 4 catalyst was then impregnated by K 2CO 3 solution to prepare K-modified catalyst. The catalysts were characterized by means of X-ray diffraction (XRD), nitrogen physisorption, scanning electrons microscopy (SEM), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H 2-TPR), and oxygen temperature-programmed desorption (O 2-TPD). The results show that Nd-Co 3O 4 and K-modified catalysts exhibit spinel structure. In contrast to bare Nd-Co 3O 4, the K-modified catalyst with higher activity is due to its weaker strength of Co-O bond and easier desorption of surface oxygen species. In addition, over 90% conversion of N 2O can be reached over 0.02K/0.01Nd-Co 3O 4 at 350 ℃ for 40 h under the co-presence of oxygen and steam in feed gases.展开更多
CO_(2)sequestration through steel slag is one of the effective approaches to simultaneously realize the resource utilization of industrial solid waste,reduce carbon emissions,and enhance the stability of steel slag as...CO_(2)sequestration through steel slag is one of the effective approaches to simultaneously realize the resource utilization of industrial solid waste,reduce carbon emissions,and enhance the stability of steel slag as a construction base,with considerable application prospects.Nevertheless,the components responsible for CO_(2)sequestration in steel slag predominantly exist as silicates,whose chemical inertness leads to suboptimal CO_(2)sequestration efficiency in the slag.Based on the strategy of activating the silicate components in steel slag with the alkali metal potassium(K)to improve the CO_(2)sequestration performance of steel slag,both experiments and theoretical calculations were performed to give a deep insight into the effect and mechanism of K modification on enhancing the CO_(2)sequestration capability of steel slag.In experiments,CO_(2)sequestration capacity of steel slag modified with 3 wt.%K reached 100.15 g/kg at 1000 K.Theoretical analysis has revealed that although K exhibits low reactivity,it enhances the electronic transition and amplifies charge localization at specific sites within Ca_(2)SiO_(4),consequently improving its CO_(2)sequestration capacity.However,an excessive doping of K led to the partial inactivation of some active sites within Ca_(2)SiO_(4).Furthermore,CO_(2)chemisorption on Ca_(2)SiO_(4)surface predominantly occurs through the chelate configuration of CO_(3)^(2−),suggesting the formation of a CaCO_(3)precursor.Thus,both the experimental results and theoretical calculations reveal the role of K on enhancing CO_(2)sequestration capability of steel slag.In summary,K modification offers promising prospects for improving CO_(2)sequestration properties of steel slag and provides support for the industrial implementation of carbon sequestration by steel slag.展开更多
基金the Key Research and Development Program of MOST(No.2017YFE0131200)for collaboration between China and Polandthe National Natural Science Foundation of China(Nos.22072095 and U1908204)+5 种基金University Joint Education Project for China-Central and Eastern European Countries(No.2021097)National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2018A04)Liaoning Provincial central government guides local science and technology development funds(No.2022JH6/100100052)Major/Key Project of Graduate Education and Teaching Reform of Shenyang Normal University(No.YJSJG120210008/YJSJG220210022)University level innovation team of Shenyang Normal Universityand Major Incubation Program of Shenyang Normal University(No.ZD201901)。
文摘Air pollution from particulate matter produced by incomplete combustion of diesel fuel has become a serious environmental pollution problem,which can be addressed by catalytic combustion.In this work,a series of K-modified MnO_(δ)catalysts with different microstructures were synthesized by the hydrothermal method,the relationship between structure of the catalysts and their catalytic performance for soot combustion was studied by characterization techniques and density functional theory(DFT)calculations.Results showed that the prepared catalysts had good catalytic performance for soot combustion and could completely oxidize soot at temperatures below 400℃.The cryptomelane-type K_(2−x)Mn_(8)O_(16)(K-OMS-2)with tunnel structure had excellent NO oxidation capacity and abundance of Mn^(4+)ions(Mn^(4+)/Mn^(3+)=1.24)with good redox ability,it demonstrated better soot combustion performance than layered birnessite-type K_(2)Mn_(4)O_(8)(K-OL-1).The T_(10),T_(50),T_(90)temperatures of KOMS-2 were 269,314,346℃,respectively.The K-OMS-2 catalyst also showed excellent stability after five catalytic cycles,with T_(10),T_(50),T_(90)values holding in the ranges of 270±2,316±2,348±3℃,respectively.
基金The project was supported by the Shandong Natural Science Foundation (ZR2017MB020)Graduate Innovation Foundation of Yantai University (YDYB1909).
文摘Nd-Co 3O 4 catalysts were prepared by hydrothermal and co-precipitation methods to catalyze the decomposition of N 2O. The catalysts prepared by hydrothermal method showed higher activity. Among the hydrothermal Nd-Co 3O 4 catalysts, the catalyst with Nd/Co molar ratio of 0.01 had higher activity. 0.01Nd-Co 3O 4 catalyst was then impregnated by K 2CO 3 solution to prepare K-modified catalyst. The catalysts were characterized by means of X-ray diffraction (XRD), nitrogen physisorption, scanning electrons microscopy (SEM), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H 2-TPR), and oxygen temperature-programmed desorption (O 2-TPD). The results show that Nd-Co 3O 4 and K-modified catalysts exhibit spinel structure. In contrast to bare Nd-Co 3O 4, the K-modified catalyst with higher activity is due to its weaker strength of Co-O bond and easier desorption of surface oxygen species. In addition, over 90% conversion of N 2O can be reached over 0.02K/0.01Nd-Co 3O 4 at 350 ℃ for 40 h under the co-presence of oxygen and steam in feed gases.
基金supported by China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202202)Major Industry Innovation Plan of Anhui Province(AHZDCYCX-LSDT2023-01).
文摘CO_(2)sequestration through steel slag is one of the effective approaches to simultaneously realize the resource utilization of industrial solid waste,reduce carbon emissions,and enhance the stability of steel slag as a construction base,with considerable application prospects.Nevertheless,the components responsible for CO_(2)sequestration in steel slag predominantly exist as silicates,whose chemical inertness leads to suboptimal CO_(2)sequestration efficiency in the slag.Based on the strategy of activating the silicate components in steel slag with the alkali metal potassium(K)to improve the CO_(2)sequestration performance of steel slag,both experiments and theoretical calculations were performed to give a deep insight into the effect and mechanism of K modification on enhancing the CO_(2)sequestration capability of steel slag.In experiments,CO_(2)sequestration capacity of steel slag modified with 3 wt.%K reached 100.15 g/kg at 1000 K.Theoretical analysis has revealed that although K exhibits low reactivity,it enhances the electronic transition and amplifies charge localization at specific sites within Ca_(2)SiO_(4),consequently improving its CO_(2)sequestration capacity.However,an excessive doping of K led to the partial inactivation of some active sites within Ca_(2)SiO_(4).Furthermore,CO_(2)chemisorption on Ca_(2)SiO_(4)surface predominantly occurs through the chelate configuration of CO_(3)^(2−),suggesting the formation of a CaCO_(3)precursor.Thus,both the experimental results and theoretical calculations reveal the role of K on enhancing CO_(2)sequestration capability of steel slag.In summary,K modification offers promising prospects for improving CO_(2)sequestration properties of steel slag and provides support for the industrial implementation of carbon sequestration by steel slag.
