Titanium silicalite-1 (TS-1) zeolite,as a promising shape-selective catalyst,has excellent catalytic activity in many oxidation reactions.However,there are still challenges to rapidly synthesize TS-1 and achieve a hig...Titanium silicalite-1 (TS-1) zeolite,as a promising shape-selective catalyst,has excellent catalytic activity in many oxidation reactions.However,there are still challenges to rapidly synthesize TS-1 and achieve a high content of Ti in TS-1 without anatase TiO_(2).In this work,a high-efficiency strategy has been proposed by using 1,3,5-benzenetricarboxylic acid (H_(3)BTC) as a crystallization modifier to rapidly synthesize enhanced-Ti TS-1 zeolite without extra-framework anatase TiO_(2).In such a synthetic system,a mixed liquid–solid precursor phase is formed within 4.5 hours,and then TS-1 crystals can be produced within one day based on the special combination mechanism of liquid-phase and solid-phase conversion.Ti species enter into the TS-1 framework by the transformation from the liquid phase to crystals as well as by the in situ transformation of the solid phase,which makes the content of framework Ti increase significantly,and the Si/Ti ratio can reach 48.5 without any anatase TiO_(2).In the epoxidation of 1-hexene with H_(2)O_(2) as an oxidant,the conversion of alkene over the synthesized TS-1 was improved by 8.01% compared to the traditional TS-1 (18.11% vs.10.10%).The high-efficiency strategy reported in this paper will provide new opportunities for further promoting the industrial application of TS-1 zeolite.展开更多
Controlling the electron spin state on the catalyst surface can regulate the reaction activity,rate,and selectivity of surface reactions.However,there are still many challenges in exploring new strategies for electron...Controlling the electron spin state on the catalyst surface can regulate the reaction activity,rate,and selectivity of surface reactions.However,there are still many challenges in exploring new strategies for electron spin regulation and mechanisms of the electron spin effect.Herein,we reported a method of using BCDs loading to change the electron spin density of magnetic Co_(3)O_(4).Octahedral Co^(3+)(Oh)-O with a t_(2g)^(6)e_(g)^(0) configuration transformed into Co^(2+)(Oh)-O with a t_(2g)^(5)e_(g)^(2) configuration after BCDs loading showed excellent activity in the electrocatalytic nitrate reduction reaction,achieving a maximum NH4+Faradaic efficiency of 94.6±0.9% and high stability.Experimental results and theoretical calculations have found that high activity is attributed to the spin density regulation changing the rate-determining step and reducing the energy it needs to overcome.This work expands the spin density regulation methods and provides a new perspective for understanding the mechanisms of carbon dot materials in electrocatalytic reactions.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.21671075 and 21621001)the 111 Project(No.B17020).
文摘Titanium silicalite-1 (TS-1) zeolite,as a promising shape-selective catalyst,has excellent catalytic activity in many oxidation reactions.However,there are still challenges to rapidly synthesize TS-1 and achieve a high content of Ti in TS-1 without anatase TiO_(2).In this work,a high-efficiency strategy has been proposed by using 1,3,5-benzenetricarboxylic acid (H_(3)BTC) as a crystallization modifier to rapidly synthesize enhanced-Ti TS-1 zeolite without extra-framework anatase TiO_(2).In such a synthetic system,a mixed liquid–solid precursor phase is formed within 4.5 hours,and then TS-1 crystals can be produced within one day based on the special combination mechanism of liquid-phase and solid-phase conversion.Ti species enter into the TS-1 framework by the transformation from the liquid phase to crystals as well as by the in situ transformation of the solid phase,which makes the content of framework Ti increase significantly,and the Si/Ti ratio can reach 48.5 without any anatase TiO_(2).In the epoxidation of 1-hexene with H_(2)O_(2) as an oxidant,the conversion of alkene over the synthesized TS-1 was improved by 8.01% compared to the traditional TS-1 (18.11% vs.10.10%).The high-efficiency strategy reported in this paper will provide new opportunities for further promoting the industrial application of TS-1 zeolite.
基金supported by the National Natural Science Foundation of China(No.22205213)the China Postdoctoral Science Foundation(2020M682332,2021T140614)+1 种基金the Natural Science Foundation of Henan Province(222300420287)the Henan Postdoctoral Foundation(202003015).
文摘Controlling the electron spin state on the catalyst surface can regulate the reaction activity,rate,and selectivity of surface reactions.However,there are still many challenges in exploring new strategies for electron spin regulation and mechanisms of the electron spin effect.Herein,we reported a method of using BCDs loading to change the electron spin density of magnetic Co_(3)O_(4).Octahedral Co^(3+)(Oh)-O with a t_(2g)^(6)e_(g)^(0) configuration transformed into Co^(2+)(Oh)-O with a t_(2g)^(5)e_(g)^(2) configuration after BCDs loading showed excellent activity in the electrocatalytic nitrate reduction reaction,achieving a maximum NH4+Faradaic efficiency of 94.6±0.9% and high stability.Experimental results and theoretical calculations have found that high activity is attributed to the spin density regulation changing the rate-determining step and reducing the energy it needs to overcome.This work expands the spin density regulation methods and provides a new perspective for understanding the mechanisms of carbon dot materials in electrocatalytic reactions.
