Most current catalyst preparation methods cause pollution to air, water and land with the use of hazardous chemicals, lengthy operation time, high energy input and excessive water usage. The development of green catal...Most current catalyst preparation methods cause pollution to air, water and land with the use of hazardous chemicals, lengthy operation time, high energy input and excessive water usage. The development of green catalyst preparation is necessary to prevent and eliminate waste from each step of the catalyst preparation. We summarize recent progress in the application of cold plasmas for green catalyst preparation. Cold plasma preparation can reduce the catalyst size, improve the dispersion and enhance catalyst-support interaction with the use of less or no hazardous chemicals. These improvements also lead to the enhancement of catalyst activity and stability. An alternative room temperature electron reduction with a non-hydrogen plasma as an electron source was developed for the reduction of noble metal ions in which no hazardous chemical reducing agent or hydrogen was needed. This creates many opportunities for the development of supported catalysts with heat sensitive substrates, including metal organic frameworks （MOFs）, covalent organic framework（COFs）, high surface area carbon, peptide, DNA, proteins and others. A novel floating metal catalyst on a water（or solution） surface has been established. Template removal using low temperature cold plasmas also leads to the formation of high surface area porous materials with characteristics that are normally only obtainable with high temperature calcination, but sintering can be avoided. Micro combustion has been developed for the removal of carbon template using cold plasma. This is promising for preparing many structured oxides in a simple way with no use of auxiliary chemicals. Many opportunities exist for the use of cold plasmas to make multi-metallic oxides. Some future development ideas are addressed.展开更多
“Living" radical polymerization of methyl methacrylate was investigated using a new reaction system,ethyl 2-bromoisobutyrate/CuBr/[mim][HCOO]/MMA,in which [mim][HCOO] ionic liquid was a good solvent to CuBr.Poly...“Living" radical polymerization of methyl methacrylate was investigated using a new reaction system,ethyl 2-bromoisobutyrate/CuBr/[mim][HCOO]/MMA,in which [mim][HCOO] ionic liquid was a good solvent to CuBr.Polymerization of methyl methacrylate was carried out in [mim][HCOO] in the absence of any organic ligands.The polymerization mechanism belongs to an ATRP process.The polymerization was closely controlled and was a fast reaction when compared to polymerization in non-polar solvents in [mim][HCOO] at 50℃.The polymers were easily separated from the catalyst.Analysis of the PMMA for residual copper by atomic absorption spectrophotometer,shows a copper content of 3.80×10 -3 %(1% is expected, if no copper is removed).展开更多
基金supported by the National Natural Science Foundation of China(20990223 and 21476157)~~
文摘Most current catalyst preparation methods cause pollution to air, water and land with the use of hazardous chemicals, lengthy operation time, high energy input and excessive water usage. The development of green catalyst preparation is necessary to prevent and eliminate waste from each step of the catalyst preparation. We summarize recent progress in the application of cold plasmas for green catalyst preparation. Cold plasma preparation can reduce the catalyst size, improve the dispersion and enhance catalyst-support interaction with the use of less or no hazardous chemicals. These improvements also lead to the enhancement of catalyst activity and stability. An alternative room temperature electron reduction with a non-hydrogen plasma as an electron source was developed for the reduction of noble metal ions in which no hazardous chemical reducing agent or hydrogen was needed. This creates many opportunities for the development of supported catalysts with heat sensitive substrates, including metal organic frameworks （MOFs）, covalent organic framework（COFs）, high surface area carbon, peptide, DNA, proteins and others. A novel floating metal catalyst on a water（or solution） surface has been established. Template removal using low temperature cold plasmas also leads to the formation of high surface area porous materials with characteristics that are normally only obtainable with high temperature calcination, but sintering can be avoided. Micro combustion has been developed for the removal of carbon template using cold plasma. This is promising for preparing many structured oxides in a simple way with no use of auxiliary chemicals. Many opportunities exist for the use of cold plasmas to make multi-metallic oxides. Some future development ideas are addressed.
文摘“Living" radical polymerization of methyl methacrylate was investigated using a new reaction system,ethyl 2-bromoisobutyrate/CuBr/[mim][HCOO]/MMA,in which [mim][HCOO] ionic liquid was a good solvent to CuBr.Polymerization of methyl methacrylate was carried out in [mim][HCOO] in the absence of any organic ligands.The polymerization mechanism belongs to an ATRP process.The polymerization was closely controlled and was a fast reaction when compared to polymerization in non-polar solvents in [mim][HCOO] at 50℃.The polymers were easily separated from the catalyst.Analysis of the PMMA for residual copper by atomic absorption spectrophotometer,shows a copper content of 3.80×10 -3 %(1% is expected, if no copper is removed).
