The preparation and application of supported gold and copper catalysts are fundamentally and practically very important.Herein,we confirm that the Au-Cu promoted In2O3 catalyst demonstrates a significant electro...The preparation and application of supported gold and copper catalysts are fundamentally and practically very important.Herein,we confirm that the Au-Cu promoted In2O3 catalyst demonstrates a significant electronic metal-support interaction(EMSI),which plays a critical role in CO2 hydrogenation to methanol and leads to significantly improved activity,compared to the mono-metallic Au and Cu promoted In2O3catalysts.This interaction arises from electron transfer between the oxygen deficient In2O3 support and the bimetallic clusters,rendering both Au and Cu clusters positively charged.The presence of Cu3+stabilizes and optimizes the content of oxygen vacancies,leading to a more pronounced positive charge on Au clusters(Au3+).The ability to activate H2 is thus enhanced.CO adsorption on Au-Cu/In2O3 is also stronger than Au/In2O3.This results in higher methanol selectivity of Au-Cu/In2O3,with which CO hydrogenation pathway is taken for CO2 hydrogenation to methanol.The enhanced H2 activation and stronger CO adsorption over Au-Cu/In2O3 are key factors in boosting the activity for methanol formation from CO2hvdrogenation.展开更多
Comprehensive analysis of the connection be-tween surface metal species and the mechanism of hydrogen(H2)generation on TiO2provides important new information for the develop-ment of more effective catalysts for ...Comprehensive analysis of the connection be-tween surface metal species and the mechanism of hydrogen(H2)generation on TiO2provides important new information for the develop-ment of more effective catalysts for H2 produc-tion.We have systematically investigated the mechanism of catalytic H2 generation on the Cu10/TiO2,Au10/TiO2,Au8Cu2/TiO2and Cu1/Au8Cu2/TiO2surfaces using density func-tional theory.Our results demonstrate an O-Hδ+···Hδ−-M type transition state for H2 production,and the Au8Cu2(0.54 eV)bimetal-lic cluster catalyst exhibits more activity in comparison to the Cu10(0.63 eV)and Au10(0.88 eV)cluster catalysts on the TiO2surface.On the Cu1/Au8Cu2/TiO2surface,we found that Au8Cu2clusters act as electron donors,while Cu single atom acts as an electron acceptor.Therefore,the Au8Cu2bimetallic catalyst has a low energy barrier(0.58 eV)in the reductive reaction of H2 production in water,but Cu single atom as the catalytic center has a higher en-ergy barrier(1.49 eV).This implies that bimetallic catalysts may be able to catalyze the wa-ter dehydrogenation reaction more successfully,which would be important knowledge for comprehending and refining the photocatalytic H2 generation process.展开更多
Au nanoclusters(NCs)with atomic-level precision represent an ideal model catalyst enabling efficient CO2-to-chemical conversion,yet the catalytic performance of distinct active sites in Au NCs remains poorly unders...Au nanoclusters(NCs)with atomic-level precision represent an ideal model catalyst enabling efficient CO2-to-chemical conversion,yet the catalytic performance of distinct active sites in Au NCs remains poorly understood.In this work,ligand-shell engineering has been successfully carried out through a"ligand-stripping pyrolysis"strategy to obtain modified Au25 NCs for electrocatalytic CO2 reduction reaction(eCO2RR).Significantly,in situ pyrolysis techniques and structural characterization identify that the exposure of S/Au active sites has been precisely controlled during the adjusted thermal decomposition of the Au NCs,which establishs a clear site-product relationship.The CO/H2 molar ratio can be precisely adjusted across an exceptionally wide range(0.26–25.47)–a span that encompasses key industrially relevant ratios,such as the 1:2 ratio optimal for Fischer-Tropsch synthesis.Molecular dynamics(MD)simulations quantitatively disclose the interaction trend between exposed S/Au sites and CO2.S sites exhibit a superior CO2 affinity,with the local CO2 concentration increasing as S-site density increases,thereby kinetically promoting eCO2RR.Theoretical calculations also reveal that S sites facilitate the stabilization of *CO2 and *CO intermediates and promote electron transfer.In contrast,Au sites are energetically more favorable for the hydrogen evolution reaction.This study establishes an ideal platform for investigating structure-performance relationships of atomically precise NCs and provides guidance for designing metal NCs-based catalysts.展开更多
The interface modulation significantly affects the photocatalytic performances of supported metal phthalocyanines(MPc)-based systems.Herein,ZnPc was loaded on nanosized Au-modified TiO2nanosheets(Au-T)to obtain wid...The interface modulation significantly affects the photocatalytic performances of supported metal phthalocyanines(MPc)-based systems.Herein,ZnPc was loaded on nanosized Au-modified TiO2nanosheets(Au-T)to obtain wide-spectrum ZnPc/Au-T photocatalysts.Compared with large Au NP(8 nm)-mediated ZnPc/Au-T photocatalyst,ultrasmall Au NP(3 nm)-mediated one shows advantageous photoactivity,achieving 3-and 10-fold CO2conversion rates compared with reference ZnPc/T and pristine TiO2nanosheets,respectively.Employing monochromatic beam-assisted surface photovoltage and photocurrent action,etc.,the introduction of ultrasmall Au NPs more effectively facilitates intrinsic interfacial charge transfer.Moreover,ZnP c molecules are found more dispersed with the existence of small Au NPs hence exposing abundant Zn2+sites as the catalytic center for CO2reduction.This work provides a feasible design strategy and renewed recognition for supported MPc-based photocatalyst systems.展开更多
The production of renewable methanol(CH3OH)via the photocatalytic hydrogenation of CO2 is an ideal method to ameliorate energy shortages and mitigate CO2 emissions:however,the highly selective synthesis of me...The production of renewable methanol(CH3OH)via the photocatalytic hydrogenation of CO2 is an ideal method to ameliorate energy shortages and mitigate CO2 emissions:however,the highly selective synthesis of methanol at atmospheric pressure remains challenging owing to the competing reverse water-gas shift(RWGS)reaction.Herein,we present a novel approach for the synthesis of CH3OH via photocatalytic CO2 hydrogenation using a catalyst featuring highly dispersed Au nanoparticles loaded on oxygen vacancy(OV)-rich molybdenum dioxide(MoO2),resulting in a remarkable selectivity of 43.78%.The active sites in the Au/MoO2 catalyst are high-density Au-oxygen vacancies,which synergistically promote the tandem methanol synthesis via an initial RWGS reaction and subsequent CO hydrogenation.This work provides comprehensive insights into the design of metal-vacancy synergistic sites for the highly selective photocatalytic hydrogenation of CO2 to CH3OH.展开更多
Hydrogen peroxide(H2O2),a versatile green oxidant and energy carrier,faces production challenges due to the energy-intensive anthraquinone process.Photocatalytic H2O2synthesis via the two-electron oxygen r...Hydrogen peroxide(H2O2),a versatile green oxidant and energy carrier,faces production challenges due to the energy-intensive anthraquinone process.Photocatalytic H2O2synthesis via the two-electron oxygen reduction reaction(2e–ORR)offers a sustainable alternative,but its efficiency is limited by sluggish charge transfer and insufficient active sites.Here,we design a dual-modulation strategy that combines defect-induced electronic tuning with piezoelectric polarization to enhance surface catalytic processes.Specifically,anchoring Au nanoparticles on N-deficient graphitic carbon nitride(CNNv-Au)allows N vacancies to modulate the electronic structure of the Au nanoparticles,increasing the proportion of electron-deficient Auδ+sites and enhancing Au–O2interactions,while the piezoelectric field simultaneously facilitates charge separation and directs electrons toward the adsorbed O2molecules.In-situ X-ray photoelectron spectroscopy(XPS)under simulated catalytic conditions revealed a 0.5 eV Au 4f shift toward higher binding energy,confirming enhanced electron transfer from Auδ+sites to adsorbed O2under light irradiation.Synergistic effects of these modifications elevate the H2O2production rate from 247.0 to 1788.5μmol g‒1 h‒1,a 7.2-fold enhancement.Combined XPS,electron paramagnetic resonance,density functional theory,and in-situ diffuse reflectance infrared Fourier transformed spectroscopy analyses confirm that N vacancies induce local polarization of Au sites,optimizing O2activation and intermediate stabilization.This work demonstrates a dual modulation strategy,defect-induced electronic tuning and piezoelectric polarization,to enhance surface catalytic processes,providing a blueprint for efficient photocatalytic H2O2generation.展开更多
Recently, the noble metal Au has been widely applied as the cocatalyst for improving the photocatalytic reduction of CO2. However, the metallic Au exhibits weak adsorption strength towards CO2 due to its intrins...Recently, the noble metal Au has been widely applied as the cocatalyst for improving the photocatalytic reduction of CO2. However, the metallic Au exhibits weak adsorption strength towards CO2 due to its intrinsic electronic structure with d-orbitals fully filled, thus limiting the activation and reduction of CO2. To address this issue and maximize the photoreduction of CO2, herein we have designed Au@CZS@MO-400 triple-shelled hollow nanospheres by depositing Cd0.7Zn0.3S (CZS) on the outer surface of the MO-400 (MnO2 annealed at 400 ℃) hollow nanospheres and then Au nanoparticles on the CZS surface. It is manifested that the resultant 3%Au@CZS@MO-400 achieves a remarkably boosted photoreduction of CO2 with the CO/CH4 yield rates as high as 68.25/12.42 µmol g-1 h-1, increased by 3.7/1.5 times over MO-400 and 12.9/1.5 times over CZS. The combined analyses from X-ray photoelectron spectroscopy and density functional theory calculations confirm the creation of electron-deficient Auδ+ active sites by modulating their electron configuration by CZS, consequently decreasing the CO2-Au antibonding-orbital occupancy to reinforce the adsorption strength of CO2 onto the Au active sites and in turn boost the photoreduction of CO2. Moreover, it is demonstrated that the Au@CZS@MO-400 hollow nanospheres are quite efficient for supplying the Au cocatalyst with photoelectrons for CO2 reduction reactions due to the good energy band matching, unique hollow structure and high electron spin polarization of MO-400. This work provides important guidance for understanding and modifying photocatalysts to maximize their photoreduction of CO2.展开更多
基金supported by the National Natural Science Foundation of China(22138009)the Fundamental Research Funds for the Central Universities of China。
摘要The preparation and application of supported gold and copper catalysts are fundamentally and practically very important.Herein,we confirm that the Au-Cu promoted In2O3 catalyst demonstrates a significant electronic metal-support interaction(EMSI),which plays a critical role in CO2 hydrogenation to methanol and leads to significantly improved activity,compared to the mono-metallic Au and Cu promoted In2O3catalysts.This interaction arises from electron transfer between the oxygen deficient In2O3 support and the bimetallic clusters,rendering both Au and Cu clusters positively charged.The presence of Cu3+stabilizes and optimizes the content of oxygen vacancies,leading to a more pronounced positive charge on Au clusters(Au3+).The ability to activate H2 is thus enhanced.CO adsorption on Au-Cu/In2O3 is also stronger than Au/In2O3.This results in higher methanol selectivity of Au-Cu/In2O3,with which CO hydrogenation pathway is taken for CO2 hydrogenation to methanol.The enhanced H2 activation and stronger CO adsorption over Au-Cu/In2O3 are key factors in boosting the activity for methanol formation from CO2hvdrogenation.
基金supported by the National Natural Science Foundation of China(No.22473107)。
摘要Comprehensive analysis of the connection be-tween surface metal species and the mechanism of hydrogen(H2)generation on TiO2provides important new information for the develop-ment of more effective catalysts for H2 produc-tion.We have systematically investigated the mechanism of catalytic H2 generation on the Cu10/TiO2,Au10/TiO2,Au8Cu2/TiO2and Cu1/Au8Cu2/TiO2surfaces using density func-tional theory.Our results demonstrate an O-Hδ+···Hδ−-M type transition state for H2 production,and the Au8Cu2(0.54 eV)bimetal-lic cluster catalyst exhibits more activity in comparison to the Cu10(0.63 eV)and Au10(0.88 eV)cluster catalysts on the TiO2surface.On the Cu1/Au8Cu2/TiO2surface,we found that Au8Cu2clusters act as electron donors,while Cu single atom acts as an electron acceptor.Therefore,the Au8Cu2bimetallic catalyst has a low energy barrier(0.58 eV)in the reductive reaction of H2 production in water,but Cu single atom as the catalytic center has a higher en-ergy barrier(1.49 eV).This implies that bimetallic catalysts may be able to catalyze the wa-ter dehydrogenation reaction more successfully,which would be important knowledge for comprehending and refining the photocatalytic H2 generation process.
摘要Au nanoclusters(NCs)with atomic-level precision represent an ideal model catalyst enabling efficient CO2-to-chemical conversion,yet the catalytic performance of distinct active sites in Au NCs remains poorly understood.In this work,ligand-shell engineering has been successfully carried out through a"ligand-stripping pyrolysis"strategy to obtain modified Au25 NCs for electrocatalytic CO2 reduction reaction(eCO2RR).Significantly,in situ pyrolysis techniques and structural characterization identify that the exposure of S/Au active sites has been precisely controlled during the adjusted thermal decomposition of the Au NCs,which establishs a clear site-product relationship.The CO/H2 molar ratio can be precisely adjusted across an exceptionally wide range(0.26–25.47)–a span that encompasses key industrially relevant ratios,such as the 1:2 ratio optimal for Fischer-Tropsch synthesis.Molecular dynamics(MD)simulations quantitatively disclose the interaction trend between exposed S/Au sites and CO2.S sites exhibit a superior CO2 affinity,with the local CO2 concentration increasing as S-site density increases,thereby kinetically promoting eCO2RR.Theoretical calculations also reveal that S sites facilitate the stabilization of *CO2 and *CO intermediates and promote electron transfer.In contrast,Au sites are energetically more favorable for the hydrogen evolution reaction.This study establishes an ideal platform for investigating structure-performance relationships of atomically precise NCs and provides guidance for designing metal NCs-based catalysts.
基金supported by the National Natural Science Foundation of China(Nos.U2102211 and 22378101)the Fundamental Research Foundation for Universities of Heilongjiang Province(No.2021-KYYWF-0004)the Science Fund for Distinguished Young Scholars of Heilongjiang University(No.JCL202102)。
摘要The interface modulation significantly affects the photocatalytic performances of supported metal phthalocyanines(MPc)-based systems.Herein,ZnPc was loaded on nanosized Au-modified TiO2nanosheets(Au-T)to obtain wide-spectrum ZnPc/Au-T photocatalysts.Compared with large Au NP(8 nm)-mediated ZnPc/Au-T photocatalyst,ultrasmall Au NP(3 nm)-mediated one shows advantageous photoactivity,achieving 3-and 10-fold CO2conversion rates compared with reference ZnPc/T and pristine TiO2nanosheets,respectively.Employing monochromatic beam-assisted surface photovoltage and photocurrent action,etc.,the introduction of ultrasmall Au NPs more effectively facilitates intrinsic interfacial charge transfer.Moreover,ZnP c molecules are found more dispersed with the existence of small Au NPs hence exposing abundant Zn2+sites as the catalytic center for CO2reduction.This work provides a feasible design strategy and renewed recognition for supported MPc-based photocatalyst systems.
摘要The production of renewable methanol(CH3OH)via the photocatalytic hydrogenation of CO2 is an ideal method to ameliorate energy shortages and mitigate CO2 emissions:however,the highly selective synthesis of methanol at atmospheric pressure remains challenging owing to the competing reverse water-gas shift(RWGS)reaction.Herein,we present a novel approach for the synthesis of CH3OH via photocatalytic CO2 hydrogenation using a catalyst featuring highly dispersed Au nanoparticles loaded on oxygen vacancy(OV)-rich molybdenum dioxide(MoO2),resulting in a remarkable selectivity of 43.78%.The active sites in the Au/MoO2 catalyst are high-density Au-oxygen vacancies,which synergistically promote the tandem methanol synthesis via an initial RWGS reaction and subsequent CO hydrogenation.This work provides comprehensive insights into the design of metal-vacancy synergistic sites for the highly selective photocatalytic hydrogenation of CO2 to CH3OH.
摘要Hydrogen peroxide(H2O2),a versatile green oxidant and energy carrier,faces production challenges due to the energy-intensive anthraquinone process.Photocatalytic H2O2synthesis via the two-electron oxygen reduction reaction(2e–ORR)offers a sustainable alternative,but its efficiency is limited by sluggish charge transfer and insufficient active sites.Here,we design a dual-modulation strategy that combines defect-induced electronic tuning with piezoelectric polarization to enhance surface catalytic processes.Specifically,anchoring Au nanoparticles on N-deficient graphitic carbon nitride(CNNv-Au)allows N vacancies to modulate the electronic structure of the Au nanoparticles,increasing the proportion of electron-deficient Auδ+sites and enhancing Au–O2interactions,while the piezoelectric field simultaneously facilitates charge separation and directs electrons toward the adsorbed O2molecules.In-situ X-ray photoelectron spectroscopy(XPS)under simulated catalytic conditions revealed a 0.5 eV Au 4f shift toward higher binding energy,confirming enhanced electron transfer from Auδ+sites to adsorbed O2under light irradiation.Synergistic effects of these modifications elevate the H2O2production rate from 247.0 to 1788.5μmol g‒1 h‒1,a 7.2-fold enhancement.Combined XPS,electron paramagnetic resonance,density functional theory,and in-situ diffuse reflectance infrared Fourier transformed spectroscopy analyses confirm that N vacancies induce local polarization of Au sites,optimizing O2activation and intermediate stabilization.This work demonstrates a dual modulation strategy,defect-induced electronic tuning and piezoelectric polarization,to enhance surface catalytic processes,providing a blueprint for efficient photocatalytic H2O2generation.
基金supported by the Gansu Province Outstanding PhD Student Fund(No.24JRRA206)the National Natural Sci-ence Foundation of China(No.52162040).
摘要Recently, the noble metal Au has been widely applied as the cocatalyst for improving the photocatalytic reduction of CO2. However, the metallic Au exhibits weak adsorption strength towards CO2 due to its intrinsic electronic structure with d-orbitals fully filled, thus limiting the activation and reduction of CO2. To address this issue and maximize the photoreduction of CO2, herein we have designed Au@CZS@MO-400 triple-shelled hollow nanospheres by depositing Cd0.7Zn0.3S (CZS) on the outer surface of the MO-400 (MnO2 annealed at 400 ℃) hollow nanospheres and then Au nanoparticles on the CZS surface. It is manifested that the resultant 3%Au@CZS@MO-400 achieves a remarkably boosted photoreduction of CO2 with the CO/CH4 yield rates as high as 68.25/12.42 µmol g-1 h-1, increased by 3.7/1.5 times over MO-400 and 12.9/1.5 times over CZS. The combined analyses from X-ray photoelectron spectroscopy and density functional theory calculations confirm the creation of electron-deficient Auδ+ active sites by modulating their electron configuration by CZS, consequently decreasing the CO2-Au antibonding-orbital occupancy to reinforce the adsorption strength of CO2 onto the Au active sites and in turn boost the photoreduction of CO2. Moreover, it is demonstrated that the Au@CZS@MO-400 hollow nanospheres are quite efficient for supplying the Au cocatalyst with photoelectrons for CO2 reduction reactions due to the good energy band matching, unique hollow structure and high electron spin polarization of MO-400. This work provides important guidance for understanding and modifying photocatalysts to maximize their photoreduction of CO2.