Pt catalysts with nitrogen-doped graphene oxide (GO) as support and CeO_(2)as promoter were prepared by impregnation method,and their catalytic oxidation of formaldehyde (HCHO) at room temperature was tested.The Pt-Ce...Pt catalysts with nitrogen-doped graphene oxide (GO) as support and CeO_(2)as promoter were prepared by impregnation method,and their catalytic oxidation of formaldehyde (HCHO) at room temperature was tested.The Pt-CeO_(2)/N-rGO (reduced GO) with a mass fraction of 0.7% Pt and 0.8%CeO_(2)exhibited an excellent catalytic performance with the 100% conversion of HCHO at room temperature.Physicochemical characterization demonstrated that nitrogendoping greatly increased the defect degree and the specific surface area of GO,enhanced the dispersion of Pt and promoted more zero-valent Pt.The synergistic effect between CeO_(2)and Pt was also beneficial to the dispersion of Pt.Nitrogen-doping promoted the production of more Ce3+ions,generating more oxygen vacancies,which was conducive to O_(2)adsorption.As a result,the catalyst exhibited enhanced redox properties,leading to the best catalytic activity.Finally,an attempt to propose the reaction mechanism of HCHO oxidation has been made.展开更多
Formaldehyde(HCHO) is one kind of common indoor toxic pollutant,the catalytic oxidation degradation of formaldehyde at room temperature is desired.In this work,a new single atomic catalyst(SAC),Al doped graphene,for t...Formaldehyde(HCHO) is one kind of common indoor toxic pollutant,the catalytic oxidation degradation of formaldehyde at room temperature is desired.In this work,a new single atomic catalyst(SAC),Al doped graphene,for the catalytic oxidation of HCHO molecules was proposed through density function theory(DFT) calculations.It is found that Al atoms can be adsorbed on graphene stably without aggre s sion.Then HCHO can be effectively oxidized into CO2 and H2 O in the presence of O2 molecules on Al doped graphene with a low energy barrier of 0.82 eV and releasing energy of 2.29 eV with the pathway of HCHO→HCOOH→CO→CO2.The oxidation reaction can happen promptly with reaction time τ=56.9 s at the speed control step at room temperature.Therefore,this work proposed a high-performance catalyst Al-doped graphene without any noble metal for HCHO oxidation at ambient temperature,and corresponding oxidation pathway and mechanism are also deeply understood.展开更多
Formaldehyde(HCHO)has been identified as one of the most common indoor pollutions nowadays.Manganese oxides(MnO_(x))are considered to be a promising catalytic material used in indoor HCHO oxidation removal due to thei...Formaldehyde(HCHO)has been identified as one of the most common indoor pollutions nowadays.Manganese oxides(MnO_(x))are considered to be a promising catalytic material used in indoor HCHO oxidation removal due to their high catalytic activity,low-cost,and environmentally friendly.In this paper,the progress in developing MnO_(x)-based catalysts for HCHO removal is comprehensively reviewed for exploring the mechanisms of catalytic oxidation and catalytic deactivation.The catalytic oxidation mechanisms based on three typical theory models(Mars-van-Krevelen,Eley-Rideal and Langmuir-Hinshelwood)are discussed and summarized.Furthermore,the research status of catalytic deactivation,catalysts’regeneration and integrated application of MnO_(x)-based catalysts for indoor HCHO removal are detailed in the review.Finally,the technical challenges in developing MnO_(x)-based catalysts for indoor HCHO removal are analyzed and the possible research direction is also proposed for overcoming the challenges toward practical application of such catalysts.展开更多
The NO oxidation processes on CrO_2(110) was investigated by virtue of DFT + U calculation together with microkinetic analysis, aiming to uncover the reaction mechanism and activity-limiting factors for CrO_2 catalyst...The NO oxidation processes on CrO_2(110) was investigated by virtue of DFT + U calculation together with microkinetic analysis, aiming to uncover the reaction mechanism and activity-limiting factors for CrO_2 catalyst. It was found that NO oxidation on CrO_2(110) has to be triggered with the lattice Obri involved(Mars-van Krevelen mechanism) rather than the Langmuir-Hinshelwood path occurring at the Cr_(5 c) sites alone. Specifically, the optimal reaction path was identified. Quantitatively, the microkinetic analysis showed that CrO_2(110) can exhibit a high turnover rate of 0.978 s^(-1) for NO oxidation at room temperature.Such an activity could originate from the bifunctional synergetic catalytic mechanism, in which the Cr_(5c)sites can exclusively adsorb NO and the Obri is very reactive and provides oxidative species. However, it is worth noting that, as the reactive Obri tightly binds NO_2, the nitrate species was found to be difficult removed and constituted the key poisoning species, eventually limiting the overall activity of CrO_2. This work demonstrated the considerable catalytic ability of CrO_2 for NO oxidation at room temperature, and the understanding may facilitate the further design of more active Cr-based catalyst.展开更多
The complete decomposition of formaldehyde(HCHO) at ambient temperature is the most potential strategy for HCHO elimination from indoor environment.Herein,extra low content of Pt nanoparticles(0.025 wt%)supported on w...The complete decomposition of formaldehyde(HCHO) at ambient temperature is the most potential strategy for HCHO elimination from indoor environment.Herein,extra low content of Pt nanoparticles(0.025 wt%)supported on water-solubility carbon nitride/ceria(Pt/gC_(3)N_(4)@CeO_(2)) was prepared for gaseous HCHO removal at ambient temperature in a simulated indoor environment.Fluorescent light(8 W) illumination could visibly boost the complete decomposition of HCHO into CO_(2) over Pt/gC_(3)N_(4)@CeO_(2).The cooperative effect in the distinct heterostructure and plenty of surface reactive oxygen species contribute primarily to the enhanced catalytic performance of Pt/g-C_(3)N_(4)@CeO_(2).Moreover,the possible mechanism of HCHO oxidation over Pt/g-C_(3)N_(4)@CeO_(2) assisted by the fluorescent light irradiation was proposed based on the physicochemical and optical characterization as well as the result of in situ diffuse reflectance infrared Fourier transform spectra.This work might shed some light on the potential application of the versatile catalysts for ambient-temperature catalytic decomposition of HCHO by making full use of the indoor energies.展开更多
基金the National Natural Science Foundation of China (Nos. U1862102, 22176010 and 21976012) for the financial supportthe Fundamental Research Funds for the Central Universities (Nos. XK1802-1, JD2117)。
文摘Pt catalysts with nitrogen-doped graphene oxide (GO) as support and CeO_(2)as promoter were prepared by impregnation method,and their catalytic oxidation of formaldehyde (HCHO) at room temperature was tested.The Pt-CeO_(2)/N-rGO (reduced GO) with a mass fraction of 0.7% Pt and 0.8%CeO_(2)exhibited an excellent catalytic performance with the 100% conversion of HCHO at room temperature.Physicochemical characterization demonstrated that nitrogendoping greatly increased the defect degree and the specific surface area of GO,enhanced the dispersion of Pt and promoted more zero-valent Pt.The synergistic effect between CeO_(2)and Pt was also beneficial to the dispersion of Pt.Nitrogen-doping promoted the production of more Ce3+ions,generating more oxygen vacancies,which was conducive to O_(2)adsorption.As a result,the catalyst exhibited enhanced redox properties,leading to the best catalytic activity.Finally,an attempt to propose the reaction mechanism of HCHO oxidation has been made.
基金National Natural Science Foundation of China (Nos.21777033,21607029 and 41425015)Science and Technology Planning Project of Guangdong Province (No. 2017B020216003)the Innovation Team Project of Guangdong Provincial Department of Education (No.2017KCXTD012)。
文摘Formaldehyde(HCHO) is one kind of common indoor toxic pollutant,the catalytic oxidation degradation of formaldehyde at room temperature is desired.In this work,a new single atomic catalyst(SAC),Al doped graphene,for the catalytic oxidation of HCHO molecules was proposed through density function theory(DFT) calculations.It is found that Al atoms can be adsorbed on graphene stably without aggre s sion.Then HCHO can be effectively oxidized into CO2 and H2 O in the presence of O2 molecules on Al doped graphene with a low energy barrier of 0.82 eV and releasing energy of 2.29 eV with the pathway of HCHO→HCOOH→CO→CO2.The oxidation reaction can happen promptly with reaction time τ=56.9 s at the speed control step at room temperature.Therefore,this work proposed a high-performance catalyst Al-doped graphene without any noble metal for HCHO oxidation at ambient temperature,and corresponding oxidation pathway and mechanism are also deeply understood.
基金the National Natural Science Foundation of China (NSFC,52070006)BeijingNova Program of Science and Technology (Z191100001119116).
文摘Formaldehyde(HCHO)has been identified as one of the most common indoor pollutions nowadays.Manganese oxides(MnO_(x))are considered to be a promising catalytic material used in indoor HCHO oxidation removal due to their high catalytic activity,low-cost,and environmentally friendly.In this paper,the progress in developing MnO_(x)-based catalysts for HCHO removal is comprehensively reviewed for exploring the mechanisms of catalytic oxidation and catalytic deactivation.The catalytic oxidation mechanisms based on three typical theory models(Mars-van-Krevelen,Eley-Rideal and Langmuir-Hinshelwood)are discussed and summarized.Furthermore,the research status of catalytic deactivation,catalysts’regeneration and integrated application of MnO_(x)-based catalysts for indoor HCHO removal are detailed in the review.Finally,the technical challenges in developing MnO_(x)-based catalysts for indoor HCHO removal are analyzed and the possible research direction is also proposed for overcoming the challenges toward practical application of such catalysts.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21333003,21622305)National Ten Thousand Talent Program for Young Top-notch Talents in ChinaThe Shanghai Shuguang Scholar Program(No.17SG30)
文摘The NO oxidation processes on CrO_2(110) was investigated by virtue of DFT + U calculation together with microkinetic analysis, aiming to uncover the reaction mechanism and activity-limiting factors for CrO_2 catalyst. It was found that NO oxidation on CrO_2(110) has to be triggered with the lattice Obri involved(Mars-van Krevelen mechanism) rather than the Langmuir-Hinshelwood path occurring at the Cr_(5 c) sites alone. Specifically, the optimal reaction path was identified. Quantitatively, the microkinetic analysis showed that CrO_2(110) can exhibit a high turnover rate of 0.978 s^(-1) for NO oxidation at room temperature.Such an activity could originate from the bifunctional synergetic catalytic mechanism, in which the Cr_(5c)sites can exclusively adsorb NO and the Obri is very reactive and provides oxidative species. However, it is worth noting that, as the reactive Obri tightly binds NO_2, the nitrate species was found to be difficult removed and constituted the key poisoning species, eventually limiting the overall activity of CrO_2. This work demonstrated the considerable catalytic ability of CrO_2 for NO oxidation at room temperature, and the understanding may facilitate the further design of more active Cr-based catalyst.
基金financially supported by the National Natural Science Foundation of China(No.21871111)the Excellent Youth Foundation of Hubei Province of China(No.2019CFA078)。
文摘The complete decomposition of formaldehyde(HCHO) at ambient temperature is the most potential strategy for HCHO elimination from indoor environment.Herein,extra low content of Pt nanoparticles(0.025 wt%)supported on water-solubility carbon nitride/ceria(Pt/gC_(3)N_(4)@CeO_(2)) was prepared for gaseous HCHO removal at ambient temperature in a simulated indoor environment.Fluorescent light(8 W) illumination could visibly boost the complete decomposition of HCHO into CO_(2) over Pt/gC_(3)N_(4)@CeO_(2).The cooperative effect in the distinct heterostructure and plenty of surface reactive oxygen species contribute primarily to the enhanced catalytic performance of Pt/g-C_(3)N_(4)@CeO_(2).Moreover,the possible mechanism of HCHO oxidation over Pt/g-C_(3)N_(4)@CeO_(2) assisted by the fluorescent light irradiation was proposed based on the physicochemical and optical characterization as well as the result of in situ diffuse reflectance infrared Fourier transform spectra.This work might shed some light on the potential application of the versatile catalysts for ambient-temperature catalytic decomposition of HCHO by making full use of the indoor energies.
基金supported by the National Key Research and Development Program (2016YFC0205900)the National Natural Science Foundation of China (21503106, 21567016)+1 种基金the Education Department of Jiangxi Province (KJLD14005)the Natural Science Foundation of Jiangxi Province (20142BAB213013 and 20151BBE50006)~~
