Calcium aluminate cement(CAC)is widely used as a binder for refractory materials,and thus the improvement in compressive strength is of vital importance for CAC applied at high temperature.For this purpose,nano-Ca_(10...Calcium aluminate cement(CAC)is widely used as a binder for refractory materials,and thus the improvement in compressive strength is of vital importance for CAC applied at high temperature.For this purpose,nano-Ca_(10)(PO_(4))_(6)(OH)_(2)additive with a ratio of 0.5–1.5 mass%was added with the water-cement ratio to be 0.4.X-ray diffraction and isothermal calorimetry analysis demonstrate that nano-Ca_(10)(PO_(4))_(6)(OH)_(2)additive can shorten the hydration process and promote the formation of main hydrates of CaAl2O4·10H2O(CAH10)and Ca2Al2O5·8H2O(C2AH8).In addition,scanning electron microscopy results suggest that nano-Ca_(10)(PO_(4))_(6)(OH)_(2)can protect CAH10 and C2AH8 from being destroyed during the calcination,guaranteeing that these thin lamellar crystals are intertwined to form the denser microstructure.Benefited from above effects,nano-Ca_(10)(PO_(4))_(6)(OH)_(2)can obviously improve the compressive strength of the CAC mortar samples cured for 7 d after calcination at 1100°C,while the improving effect is dependent upon its contents.Especially,compared with the one without the additive,the compressive strength of the sample with 1.0%nano-Ca_(10)(PO_(4))_(6)(OH)_(2)is increased by 14%.展开更多
The heterojunction effect can effectively improve the separation efficiency of the photocatalyst’s photo-generated electron and hole pairs,thereby greatly improving the photocatalytic hydrogen production performance ...The heterojunction effect can effectively improve the separation efficiency of the photocatalyst’s photo-generated electron and hole pairs,thereby greatly improving the photocatalytic hydrogen production performance of the photocatalyst.In this paper,Bi_(6)O_(6)(OH)_(3)(NO_(3))_(3)·1.5H_(2)O(BBN)and ZnO are used to construct and synthesize Bi_(6)O_(6)(OH)_(3)(NO_(3))_(3)·1.5H_(2)O/ZnO(BBN/ZnO)heterojunction photocatalyst.Under UV-vis light irradiation,the BBN/ZnO composite could generate H_(2)with a rate of 28.66μmol·g^(−1)·h^(−1),which is higher than pure BBN(0.92μmol·g^(−1)·h^(−1))and ZnO(6.54μmol·h^(−1)·g^(−1))at around 31.1 and 4.4 times,respectively.Moreover,the experimental results found that the composite still exhibits excellent photocatalytic activity and maintains a high and stable activity in the 12-hour experiment with 3 cycles.The possible mechanism to enhance the photocatalytic behavior is attributed to the expanded light absorption range,reduced surface migration resistance,and inhibited recombination of photo-generated electron and hole pairs.展开更多
基金The authors express their appreciation to the National Natural Science Foundation of China(Nos.51904021 and 51974021)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-19-008A1 and FRF-TP-19-004B2Z)+1 种基金China Postdoctoral Science Foundation(2019M660458 and 2020T130052)Beijing Excellent Talents Foundation for financial support.
文摘Calcium aluminate cement(CAC)is widely used as a binder for refractory materials,and thus the improvement in compressive strength is of vital importance for CAC applied at high temperature.For this purpose,nano-Ca_(10)(PO_(4))_(6)(OH)_(2)additive with a ratio of 0.5–1.5 mass%was added with the water-cement ratio to be 0.4.X-ray diffraction and isothermal calorimetry analysis demonstrate that nano-Ca_(10)(PO_(4))_(6)(OH)_(2)additive can shorten the hydration process and promote the formation of main hydrates of CaAl2O4·10H2O(CAH10)and Ca2Al2O5·8H2O(C2AH8).In addition,scanning electron microscopy results suggest that nano-Ca_(10)(PO_(4))_(6)(OH)_(2)can protect CAH10 and C2AH8 from being destroyed during the calcination,guaranteeing that these thin lamellar crystals are intertwined to form the denser microstructure.Benefited from above effects,nano-Ca_(10)(PO_(4))_(6)(OH)_(2)can obviously improve the compressive strength of the CAC mortar samples cured for 7 d after calcination at 1100°C,while the improving effect is dependent upon its contents.Especially,compared with the one without the additive,the compressive strength of the sample with 1.0%nano-Ca_(10)(PO_(4))_(6)(OH)_(2)is increased by 14%.
基金This work was supported by the Natural Science Foundation of Fujian Province[2020J01833]the Fujian Engineering Research Center of New Chinese lacquer Material[No.323030030702]+3 种基金the humbly acknowledge international funding provided by Fujian Agriculture and Forestry University[No.KXB16001A]the Education Research Program for Young and Middle-aged Teachers of Fujian Education Department[No.JAT190132]the open fund of the Key Laboratory of National Forestry&Grassland Bureau for Plant Fiber Functional Materials,Fujian Agriculture and Forestry University[No.2019KFJJ15]Key Laboratory of New Functional Textile Fiber and Material of Fujian Province will open fund project in 2020[MJUKF-FMSM202005,FKLTF 1708].
文摘The heterojunction effect can effectively improve the separation efficiency of the photocatalyst’s photo-generated electron and hole pairs,thereby greatly improving the photocatalytic hydrogen production performance of the photocatalyst.In this paper,Bi_(6)O_(6)(OH)_(3)(NO_(3))_(3)·1.5H_(2)O(BBN)and ZnO are used to construct and synthesize Bi_(6)O_(6)(OH)_(3)(NO_(3))_(3)·1.5H_(2)O/ZnO(BBN/ZnO)heterojunction photocatalyst.Under UV-vis light irradiation,the BBN/ZnO composite could generate H_(2)with a rate of 28.66μmol·g^(−1)·h^(−1),which is higher than pure BBN(0.92μmol·g^(−1)·h^(−1))and ZnO(6.54μmol·h^(−1)·g^(−1))at around 31.1 and 4.4 times,respectively.Moreover,the experimental results found that the composite still exhibits excellent photocatalytic activity and maintains a high and stable activity in the 12-hour experiment with 3 cycles.The possible mechanism to enhance the photocatalytic behavior is attributed to the expanded light absorption range,reduced surface migration resistance,and inhibited recombination of photo-generated electron and hole pairs.
