Catalytic conversion of nitrate(NO_(3)^(-))pollutants into ammonia(NH_(3))offers a sustainable and promising route for both wastewater treatment and NH_(3)synthesis.Alkali cations are prevalent in nitrate solutions,bu...Catalytic conversion of nitrate(NO_(3)^(-))pollutants into ammonia(NH_(3))offers a sustainable and promising route for both wastewater treatment and NH_(3)synthesis.Alkali cations are prevalent in nitrate solutions,but their roles beyond charge balance in catalytic NO_(3)^(-)conversion have been generally ignored.Herein,we report the promotion effect of K^(+)cations in KNO_(3)solution for NO_(3)^(-)reduction over a TiO_(2)-supported Ni single-atom catalyst(Ni_(1)/TiO_(2)).For photocatalytic NO_(3)^(-)reduction reaction,Ni_(1)/TiO_(2)exhibited a 1.9-fold NH_(3)yield rate with nearly 100%selectivity in KNO_(3)solution relative to that in NaNO_(3)solution.Mechanistic studies reveal that the K^(+)cations from KNO_(3)gradually bonded with the surface of Ni_(1)/TiO_(2),in situ forming a K-O-Ni moiety during reaction,whereas the Na^(+)ions were unable to interact with the catalyst in NaNO_(3)solution.The charge accumulation on the Ni sites induced by the incorporation of K atom promoted the adsorption and activation of NO_(3)^(-).Furthermore,the K-O-Ni moiety facilitated the multiple proton-electron coupling of NO_(3)^(-)into NH_(3)by stabilizing the intermediates.展开更多
Co-based catalysts are promising alternatives to precious metals for the selective and effective oxidation of 5-hydroxymethylfurfural(HMF)to the higher value-added 2,5-furandicarboxylic acid(FDCA).However,these cataly...Co-based catalysts are promising alternatives to precious metals for the selective and effective oxidation of 5-hydroxymethylfurfural(HMF)to the higher value-added 2,5-furandicarboxylic acid(FDCA).However,these catalysts still suffer from unsatisfactory activity and poor selectivity.A series of N-doped carbon-supported Co-based dual-metal nanoparticles(NPs)have been designed,among which the Co-Cu_(1.4)-CN_(x) exhibits enhanced HMF oxidative activity,achieving FDCA formation rates 4 times higher than that of pristine Co-CN_(x),with 100%FDCA selectivity.Density functional theory(DFT)calculations evidenced that the increased electron density on Co sites induced by Cu can mediate the positive electronegativity offset to downshift the dband center of Co-Cu_(1.4)-CN_(x),thus reducing the energy barriers for the conversion of HMF to FDCA.Such findings will support the development of superior non-precious metal catalysts for HMF oxidation.展开更多
Dear Editor,Zika virus(ZIKV)is a mosquito-borne,positive-stranded RNA virus first identified in 1947 in monkeys and later identified in humans in 1952(Faye et al.,2014).It is among the“TORCH”group of microorganisms ...Dear Editor,Zika virus(ZIKV)is a mosquito-borne,positive-stranded RNA virus first identified in 1947 in monkeys and later identified in humans in 1952(Faye et al.,2014).It is among the“TORCH”group of microorganisms and causes outbreaks in several countries and regions since 2007(Voordouw et al.,2019).展开更多
Developing cost-effective and high-performance oxygen evolution reaction(OER)electrocatalysts has become the intense research on pursuing emerging renewable energy conversion,in which exploring and investigating the i...Developing cost-effective and high-performance oxygen evolution reaction(OER)electrocatalysts has become the intense research on pursuing emerging renewable energy conversion,in which exploring and investigating the intrinsic nature of efficient and stable Cu Co spinel catalysts toward OER in alkaline media is highly desirable.Herein,Cu1–xCo2+xO4oxy-spinel nanoflakes are fabricated by a facile hydrothermal method with the oxidation of ammonia water.In the same condition,Cu1–xCo2+xS4thio-spinel nanospheres are formed without oxidation.In OER process,the as-obtained Cu1–xCo2+xO4nanoflakes and Cu1–xCo2+xS4nanospheres possess the anodic overpotential of 267 and 297 m V in alkaline media to drive the current density of 10 m A/cm^2,respectively,outperforming the state-of-the-art noble metal catalyst of RuO2.X-ray photoelectron spectroscopy analysis exhibits the higher ratio value of Co(Ⅲ)/Co(Ⅱ)in Cu1–xCo2+xO4than that in Cu1–xCo2+xS4,suggesting that the stronglyelectronegative oxygen efficiently predominates in regulating valence states of Co active sites in spinel structures.Remarkably,density functional theory simulation further reveals that the increased valence state of Co could accelerate the electron exchange between catalysts and oxygen adsorbates during electrocatalysis,thus contributing to the higher OER activity of Cu1–xCo2+xO4catalysts.This work provides deep insight regarding the significance of non-metal element(O and S)in Cu Co spinel structure catalysts,as well as presents a promising approach to exploit higher performance and grasp the mechanism of various non-noblemetal spinel catalysts for water oxidation.展开更多
基金financial support by the National Natural Science Foundation of China(12222508,U1932213,and 22308346)the Fundamental Research Funds for the Central Universities(WK2060000016)+5 种基金the USTC Research Funds of the Double First-Class Initiative(YD2310002005 and YD9990002014)the National Key R&D Program of China(2023YFA1506304)the Youth Innovation Promotion Association CAS(2020454)Xiaomi Young Talents ProgramJoint Funds from the Hefei National Synchrotron Radiation Laboratory(KY9990000202)Natural Science Foundation of Anhui Province(2208085QB42)。
文摘Catalytic conversion of nitrate(NO_(3)^(-))pollutants into ammonia(NH_(3))offers a sustainable and promising route for both wastewater treatment and NH_(3)synthesis.Alkali cations are prevalent in nitrate solutions,but their roles beyond charge balance in catalytic NO_(3)^(-)conversion have been generally ignored.Herein,we report the promotion effect of K^(+)cations in KNO_(3)solution for NO_(3)^(-)reduction over a TiO_(2)-supported Ni single-atom catalyst(Ni_(1)/TiO_(2)).For photocatalytic NO_(3)^(-)reduction reaction,Ni_(1)/TiO_(2)exhibited a 1.9-fold NH_(3)yield rate with nearly 100%selectivity in KNO_(3)solution relative to that in NaNO_(3)solution.Mechanistic studies reveal that the K^(+)cations from KNO_(3)gradually bonded with the surface of Ni_(1)/TiO_(2),in situ forming a K-O-Ni moiety during reaction,whereas the Na^(+)ions were unable to interact with the catalyst in NaNO_(3)solution.The charge accumulation on the Ni sites induced by the incorporation of K atom promoted the adsorption and activation of NO_(3)^(-).Furthermore,the K-O-Ni moiety facilitated the multiple proton-electron coupling of NO_(3)^(-)into NH_(3)by stabilizing the intermediates.
基金the National Natural Science Foundation of China(Nos.51902281,51801075,and 82160421)the Natural Science Foundation of Jiangsu Province(No.BK20211322)the Scientific and Technological Projects of Henan Province(No.212102210293).
文摘Co-based catalysts are promising alternatives to precious metals for the selective and effective oxidation of 5-hydroxymethylfurfural(HMF)to the higher value-added 2,5-furandicarboxylic acid(FDCA).However,these catalysts still suffer from unsatisfactory activity and poor selectivity.A series of N-doped carbon-supported Co-based dual-metal nanoparticles(NPs)have been designed,among which the Co-Cu_(1.4)-CN_(x) exhibits enhanced HMF oxidative activity,achieving FDCA formation rates 4 times higher than that of pristine Co-CN_(x),with 100%FDCA selectivity.Density functional theory(DFT)calculations evidenced that the increased electron density on Co sites induced by Cu can mediate the positive electronegativity offset to downshift the dband center of Co-Cu_(1.4)-CN_(x),thus reducing the energy barriers for the conversion of HMF to FDCA.Such findings will support the development of superior non-precious metal catalysts for HMF oxidation.
基金funded by the National Natural Science Foundation of China (NSFC,grants 81773631,to R.C.grants 81900402,to X.C.)the National Science and Technology Major Projects for“Major New Drugs Innovation and Development”,China (2018ZX09711003,to W.Z.).
文摘Dear Editor,Zika virus(ZIKV)is a mosquito-borne,positive-stranded RNA virus first identified in 1947 in monkeys and later identified in humans in 1952(Faye et al.,2014).It is among the“TORCH”group of microorganisms and causes outbreaks in several countries and regions since 2007(Voordouw et al.,2019).
基金the support from the National Natural Science Foundation of China(91750112,51801075)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX191591).D Rao gratefully acknowledges the support of Jiangsu Overseas Visiting Scholar Program for University Prominent Young and Mid-aged Teachers and Presidents.
文摘Developing cost-effective and high-performance oxygen evolution reaction(OER)electrocatalysts has become the intense research on pursuing emerging renewable energy conversion,in which exploring and investigating the intrinsic nature of efficient and stable Cu Co spinel catalysts toward OER in alkaline media is highly desirable.Herein,Cu1–xCo2+xO4oxy-spinel nanoflakes are fabricated by a facile hydrothermal method with the oxidation of ammonia water.In the same condition,Cu1–xCo2+xS4thio-spinel nanospheres are formed without oxidation.In OER process,the as-obtained Cu1–xCo2+xO4nanoflakes and Cu1–xCo2+xS4nanospheres possess the anodic overpotential of 267 and 297 m V in alkaline media to drive the current density of 10 m A/cm^2,respectively,outperforming the state-of-the-art noble metal catalyst of RuO2.X-ray photoelectron spectroscopy analysis exhibits the higher ratio value of Co(Ⅲ)/Co(Ⅱ)in Cu1–xCo2+xO4than that in Cu1–xCo2+xS4,suggesting that the stronglyelectronegative oxygen efficiently predominates in regulating valence states of Co active sites in spinel structures.Remarkably,density functional theory simulation further reveals that the increased valence state of Co could accelerate the electron exchange between catalysts and oxygen adsorbates during electrocatalysis,thus contributing to the higher OER activity of Cu1–xCo2+xO4catalysts.This work provides deep insight regarding the significance of non-metal element(O and S)in Cu Co spinel structure catalysts,as well as presents a promising approach to exploit higher performance and grasp the mechanism of various non-noblemetal spinel catalysts for water oxidation.
