The common ways to activate a chemical reaction are by heat,electric current,or light.However,mechanochemistry,where the chemical reaction is activated by applied mechanical force,is less common and only poorly unders...The common ways to activate a chemical reaction are by heat,electric current,or light.However,mechanochemistry,where the chemical reaction is activated by applied mechanical force,is less common and only poorly understood at the atomic scale.Here we report a tip-induced activation of chemical reaction of carbon monoxide to dioxide on oxidized rutile TiO_(2)(110)surface.The activation is studied by atomic force microscopy,Kelvin probe force microscopy under ultrahigh-vacuum and liquid nitrogen temperature conditions,and density functional theory(DFT)modeling.The reaction is inferred from hysteretic behavior of frequency shift signal further supported by vector force mapping of vertical and lateral forces needed to trigger the chemical reaction with torque motion of carbon monoxide towards an oxygen adatom.The reaction is found to proceed stochastically at very small tip-sample distances.Furthermore,the local contact potential difference reveals the atomic-scale charge redistribution in the reactants required to unlock the reaction.Our results open up new insights into the mechanochemistry on metal oxide surfaces at the atomic scale.展开更多
Identifying the active site of oxide-supported metal catalysts and revealing the intrinsic synergistic mechanism between metal and oxide support remain a large challenge.Herein,we report the identification and separat...Identifying the active site of oxide-supported metal catalysts and revealing the intrinsic synergistic mechanism between metal and oxide support remain a large challenge.Herein,we report the identification and separation of the Pt-O-Ti interface and TiO_(2) surface in Pt-TiO_(2)-based catalysts by depositing different thickness of TiO_(2) shell with∼0.4-nm micropores onto the surface of Pt/TiO_(2) catalyst through atomic layer deposition(ALD).In the oxidation of 3,3′,5,5′-tetramethylbenzidine(TMB)by hydrogen peroxide(H_(2)O_(2))process,the TiO_(2) microporous shells can prevent the contact between TMB and embedded Pt clusters,but not delay the diffusion of H_(2)O_(2).The heterolysis of H_(2)O_(2) to ·OH occurs on the Pt-O-Ti interface,and the generated•OH migrates to the TiO_(2) surface to supplement the surface lattice oxygen,which sequentially oxidizes TMB to oxTMB.And the synergistic effect between Pt-O-Ti interface active sties and TiO_(2) surface active sites can significantly improve the catalytic performance.Our study provides a guide for the understanding of the intrinsic synergistic mechanism between the metal and oxide support in the metal-oxide catalysts.展开更多
基金supported by a Grant-in-Aid for Scientific Research from Japan Society for the Promotion of Science(JSPS)from the Ministry of Education,Culture,Sports,Science,and Technology of Japan(Nos.JP16H06327,JP17H01061,A21J103560,and JP22H00282)supported by the International Joint Research Promotion Program of Osaka University(Nos.J171013014,J171013007,J181013004,J181013006,Ja1999001,Ja19990011,and A21J103560)+1 种基金JSPSthe National Natural Science Foundation of China(No.J191053055)supported by APVV-21-0272,VEGA-2/0070/21,VEGA-2/0125/20,VEGA-2/0131/23,and H2020 TREX GA No.952165 projects。
文摘The common ways to activate a chemical reaction are by heat,electric current,or light.However,mechanochemistry,where the chemical reaction is activated by applied mechanical force,is less common and only poorly understood at the atomic scale.Here we report a tip-induced activation of chemical reaction of carbon monoxide to dioxide on oxidized rutile TiO_(2)(110)surface.The activation is studied by atomic force microscopy,Kelvin probe force microscopy under ultrahigh-vacuum and liquid nitrogen temperature conditions,and density functional theory(DFT)modeling.The reaction is inferred from hysteretic behavior of frequency shift signal further supported by vector force mapping of vertical and lateral forces needed to trigger the chemical reaction with torque motion of carbon monoxide towards an oxygen adatom.The reaction is found to proceed stochastically at very small tip-sample distances.Furthermore,the local contact potential difference reveals the atomic-scale charge redistribution in the reactants required to unlock the reaction.Our results open up new insights into the mechanochemistry on metal oxide surfaces at the atomic scale.
基金financially supported from the National Natural Science Foundation of China(21802094,22272127,22002118,and 22172119)the National Science Fund for Distinguished Young Scholars(21825204)+1 种基金the Fundamental Research Funds for the Central Universities(D5000210666)the Natural Science Basic Research Plan in Shaanxi Province of China(2021JM-047).
文摘Identifying the active site of oxide-supported metal catalysts and revealing the intrinsic synergistic mechanism between metal and oxide support remain a large challenge.Herein,we report the identification and separation of the Pt-O-Ti interface and TiO_(2) surface in Pt-TiO_(2)-based catalysts by depositing different thickness of TiO_(2) shell with∼0.4-nm micropores onto the surface of Pt/TiO_(2) catalyst through atomic layer deposition(ALD).In the oxidation of 3,3′,5,5′-tetramethylbenzidine(TMB)by hydrogen peroxide(H_(2)O_(2))process,the TiO_(2) microporous shells can prevent the contact between TMB and embedded Pt clusters,but not delay the diffusion of H_(2)O_(2).The heterolysis of H_(2)O_(2) to ·OH occurs on the Pt-O-Ti interface,and the generated•OH migrates to the TiO_(2) surface to supplement the surface lattice oxygen,which sequentially oxidizes TMB to oxTMB.And the synergistic effect between Pt-O-Ti interface active sties and TiO_(2) surface active sites can significantly improve the catalytic performance.Our study provides a guide for the understanding of the intrinsic synergistic mechanism between the metal and oxide support in the metal-oxide catalysts.
