Due to their diverse and tunable composition,distorted lattice and excellent stability,high-entropy ceramics(HECs)hold great promise for catalysis,especially when they present as nanoparticles(NPs).However,current HEC...Due to their diverse and tunable composition,distorted lattice and excellent stability,high-entropy ceramics(HECs)hold great promise for catalysis,especially when they present as nanoparticles(NPs).However,current HECs are typically limited to bulky materials with none or fewer defects,because high synthetic temperature(e.g.,1,000–1,200°C)is usually required to highlight the entropic contribution(TΔS)inΔG=ΔH−TΔS.Being different with previous strategies,a negative Gibbs free energy for HECs crystallization is obtained by dramatically decreasing the mixing enthalpy(ΔH).Guided by this principle,single-phase highentropy La(Ni_(0.2)Mn_(0.2)Cu_(0.2)Fe_(0.2)Co_(0.2))O_(3−δ)perovskite(HE-LMO)NPs were prepared at a relatively low temperature(≤500°C).Interestingly,abundant oxygen vacancies were directly created within HE-LMO NPs,which exhibited good activity in catalytic oxidation.Meanwhile,the high-entropy structure endows as-made HE-LMO with robust stability even with 5 vol.%water in feeding gas.Density functional theory(DFT)calculations revealed that the defective sites in HE-LMO NPs facilitated the charge transfer from HE-LMO to CO,thus activating the adsorbed CO gas.The current work may inspire future design and synthesis of HECs NPs.展开更多
基金supported by National Natural Science Foundation of China(No.21776174)the National Key R&D Plan(No.2020YFB0606400)+2 种基金Shanghai Rising-Star Program(No.20QA1405200)Shanghai Jiao Tong University Scientific and Technological Innovation Funds(No.2019QYB06)China Shipbuilding Industry Corporation(CSIC)and Inner Mongolia Erdos Group.
文摘Due to their diverse and tunable composition,distorted lattice and excellent stability,high-entropy ceramics(HECs)hold great promise for catalysis,especially when they present as nanoparticles(NPs).However,current HECs are typically limited to bulky materials with none or fewer defects,because high synthetic temperature(e.g.,1,000–1,200°C)is usually required to highlight the entropic contribution(TΔS)inΔG=ΔH−TΔS.Being different with previous strategies,a negative Gibbs free energy for HECs crystallization is obtained by dramatically decreasing the mixing enthalpy(ΔH).Guided by this principle,single-phase highentropy La(Ni_(0.2)Mn_(0.2)Cu_(0.2)Fe_(0.2)Co_(0.2))O_(3−δ)perovskite(HE-LMO)NPs were prepared at a relatively low temperature(≤500°C).Interestingly,abundant oxygen vacancies were directly created within HE-LMO NPs,which exhibited good activity in catalytic oxidation.Meanwhile,the high-entropy structure endows as-made HE-LMO with robust stability even with 5 vol.%water in feeding gas.Density functional theory(DFT)calculations revealed that the defective sites in HE-LMO NPs facilitated the charge transfer from HE-LMO to CO,thus activating the adsorbed CO gas.The current work may inspire future design and synthesis of HECs NPs.
