The Cu/CeO_(2)nanoporous composite material was prepared via a one-step and energy-saving method of solution combustion synthesis(SCS).The phase composition,surface morphology and optical characteristics of Cu/CeO_(2)...The Cu/CeO_(2)nanoporous composite material was prepared via a one-step and energy-saving method of solution combustion synthesis(SCS).The phase composition,surface morphology and optical characteristics of Cu/CeO_(2)were studied.The results show that the SCS products are composed of cubic fluorite CeO_(2)and Cu.Due to the generation and escape of gas during the synthetic reaction,the SCS CeO_(2)shows porous structure,in which the mesopores(diameter 10-17 nm)nest in the wall of large pores(diameter80-300 nm).X-ray photoelectron spectroscopy(XPS)outcomes indicate that the oxygen vacancy concentration of CeO_(2)increases(18.97%-30.93%)with the increase of Cu concentration.The decoration of Cu greatly enhances the catalytic activity of CeO_(2)nanomaterials.30 wt%Cu/CeO_(2)composite material shows the best photocatalytic activities for the degradation of methyl orange(MO)(95.99%),which is about 4.3times that of CeO_(2)at the same time(120 min).UV-vis diffuse reflectance spectroscopy(DRS)results show that the semiconductor band gap is reduced with the addition of metallic Cu,which leads to the enhancement of photocatalytic activity.The free radical trapping experiments demonstrate that·O_(2)-and h+are the main active species in the photocatalytic degradation of MO.Based on the above results,a hypothesized mechanism for enhanced photocatalysis of Cu/CeO_(2)nanomaterials was proposed:the porous structure provides more reactive sites and channels for mass transfer,and the presence of metallic Cu improves the oxygen vacancy concentration of CeO_(2)and then promotes charge-carrier separation,which helps enhance the photocatalytic performance of Cu/CeO_(2).展开更多
As a class of nanomaterials with natural enzyme-like characteristics, nanozymes have shown their great potential in various applications. Reducible metal oxides featured with defect structures, and single-atom catalys...As a class of nanomaterials with natural enzyme-like characteristics, nanozymes have shown their great potential in various applications. Reducible metal oxides featured with defect structures, and single-atom catalysts with isolated metal sites are regarded as two of the most promising nanozymes. However, the strategies to construct highly performed nanozymes by combining these advantages are rarely reported. Herein, we report the coordination-unsaturated single-atomic Cu species supported on sintered CeO_(2), which combines the advantages of defect engineering and single-atom catalysis, exhibiting a largely enhanced peroxidase(POD)-like activity. The high-temperature calcination induces the transformation of inert Cu_(1)O_(4) species into coordination-unsaturated Cu_(1)O_(3) sites. This novel Cu_(1)O_(3) active sites with an unsaturated coordination work as a new type of defect sites to greatly activate the isolated Cu atoms and accelerate the dissociation of H_(2)O_(2) to form hydroxyl radicals(·OH). The obtained nanozyme with a high POD-like activity possesses low cytotoxicity, showing potential applications for the tumor inhibition in vitro and in vivo.展开更多
基金Project supported by the Fundamental Research Funds for the Central Universities(2019ZDPY20)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX21_2199)。
文摘The Cu/CeO_(2)nanoporous composite material was prepared via a one-step and energy-saving method of solution combustion synthesis(SCS).The phase composition,surface morphology and optical characteristics of Cu/CeO_(2)were studied.The results show that the SCS products are composed of cubic fluorite CeO_(2)and Cu.Due to the generation and escape of gas during the synthetic reaction,the SCS CeO_(2)shows porous structure,in which the mesopores(diameter 10-17 nm)nest in the wall of large pores(diameter80-300 nm).X-ray photoelectron spectroscopy(XPS)outcomes indicate that the oxygen vacancy concentration of CeO_(2)increases(18.97%-30.93%)with the increase of Cu concentration.The decoration of Cu greatly enhances the catalytic activity of CeO_(2)nanomaterials.30 wt%Cu/CeO_(2)composite material shows the best photocatalytic activities for the degradation of methyl orange(MO)(95.99%),which is about 4.3times that of CeO_(2)at the same time(120 min).UV-vis diffuse reflectance spectroscopy(DRS)results show that the semiconductor band gap is reduced with the addition of metallic Cu,which leads to the enhancement of photocatalytic activity.The free radical trapping experiments demonstrate that·O_(2)-and h+are the main active species in the photocatalytic degradation of MO.Based on the above results,a hypothesized mechanism for enhanced photocatalysis of Cu/CeO_(2)nanomaterials was proposed:the porous structure provides more reactive sites and channels for mass transfer,and the presence of metallic Cu improves the oxygen vacancy concentration of CeO_(2)and then promotes charge-carrier separation,which helps enhance the photocatalytic performance of Cu/CeO_(2).
基金supported by the National Key Research and Development Program of China (2021YFA1501103)the National Science Fund for Distinguished Young Scholars of China (22225110)+3 种基金the National Natural Science Foundation of China (22102088)the foundation of Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education (202202)the Taishan Scholar Project of Shandong Province of Chinathe Young Scholars Program of Shandong University。
文摘As a class of nanomaterials with natural enzyme-like characteristics, nanozymes have shown their great potential in various applications. Reducible metal oxides featured with defect structures, and single-atom catalysts with isolated metal sites are regarded as two of the most promising nanozymes. However, the strategies to construct highly performed nanozymes by combining these advantages are rarely reported. Herein, we report the coordination-unsaturated single-atomic Cu species supported on sintered CeO_(2), which combines the advantages of defect engineering and single-atom catalysis, exhibiting a largely enhanced peroxidase(POD)-like activity. The high-temperature calcination induces the transformation of inert Cu_(1)O_(4) species into coordination-unsaturated Cu_(1)O_(3) sites. This novel Cu_(1)O_(3) active sites with an unsaturated coordination work as a new type of defect sites to greatly activate the isolated Cu atoms and accelerate the dissociation of H_(2)O_(2) to form hydroxyl radicals(·OH). The obtained nanozyme with a high POD-like activity possesses low cytotoxicity, showing potential applications for the tumor inhibition in vitro and in vivo.
