It is verified that the phonon scattering process and the residual linewidthare the dominant factors of the linewidth of 2210 cm^(-1) IR absorption peak except the anomalous linewidth at 200 K. By investigating the an...It is verified that the phonon scattering process and the residual linewidthare the dominant factors of the linewidth of 2210 cm^(-1) IR absorption peak except the anomalous linewidth at 200 K. By investigating the anomalities of the peak shape and thelinewidth of the peak at 200 K, we put forward a mechanism that the T_d symmetry of defect-complex corresponding to the 2210 cm^(-1) peak can he transferred into the D_(2d) symmetry as temperature rises to above 200 K. The quantitative analysis shows that the V+4H-model is indeed of two states: The T_d configuration is stable at temperature lower than 200 K, while the D_(2d) one is stable at temperature higher than 200 K. We can draw the conclusion that the V +4H-model corresponds to the 2210 cm^(-1) IR absorption peak from the symmetric breaking mechanism, which can quantitatively fit the experimental results.展开更多
Many research works have demonstrated that the combination of atomically precise cluster deposition and theoretical calculations is able to address fundamental aspects of size-effects,cluster-support interactions,and ...Many research works have demonstrated that the combination of atomically precise cluster deposition and theoretical calculations is able to address fundamental aspects of size-effects,cluster-support interactions,and reaction mechanisms of cluster materials.Although the wet chemistry method has been widely used to synthesize nanoparticles,the gas-phase synthesis and size-selected strategy was the only method to prepare supported metal clusters with precise numbers of atoms for a long time.However,the low throughput of the physical synthesis method has severely constrained its wider adoption for catalysis applications.In this review,we introduce the latest progress on three types of cluster source which have the most promising potential for scale-up,including sputtering gas aggregation source,pulsed microplasma cluster source,and matrix assembly cluster source.While the sputtering gas aggregation source is leading ahead with a production rate of~20 mg·h^(-1),the pulsed microplasma source has the smallest physical dimensions which makes it possible to compact multiple such devices into a small volume for multiplied production rate.The matrix assembly source has the shortest development history,but already show an impressive deposition rate of~10 mg·h^(-1).At the end of the review,the possible routes for further throughput scale-up are envisaged.展开更多
文摘It is verified that the phonon scattering process and the residual linewidthare the dominant factors of the linewidth of 2210 cm^(-1) IR absorption peak except the anomalous linewidth at 200 K. By investigating the anomalities of the peak shape and thelinewidth of the peak at 200 K, we put forward a mechanism that the T_d symmetry of defect-complex corresponding to the 2210 cm^(-1) peak can he transferred into the D_(2d) symmetry as temperature rises to above 200 K. The quantitative analysis shows that the V+4H-model is indeed of two states: The T_d configuration is stable at temperature lower than 200 K, while the D_(2d) one is stable at temperature higher than 200 K. We can draw the conclusion that the V +4H-model corresponds to the 2210 cm^(-1) IR absorption peak from the symmetric breaking mechanism, which can quantitatively fit the experimental results.
基金We thank the funding received from the European Union’s Seventh Framework Programme(Grant No.FP7/2007-2013)under grant agreement No.607417(Catsense)the funding from the Innovate UK under grant agreement No.104008(ANCOP).
文摘Many research works have demonstrated that the combination of atomically precise cluster deposition and theoretical calculations is able to address fundamental aspects of size-effects,cluster-support interactions,and reaction mechanisms of cluster materials.Although the wet chemistry method has been widely used to synthesize nanoparticles,the gas-phase synthesis and size-selected strategy was the only method to prepare supported metal clusters with precise numbers of atoms for a long time.However,the low throughput of the physical synthesis method has severely constrained its wider adoption for catalysis applications.In this review,we introduce the latest progress on three types of cluster source which have the most promising potential for scale-up,including sputtering gas aggregation source,pulsed microplasma cluster source,and matrix assembly cluster source.While the sputtering gas aggregation source is leading ahead with a production rate of~20 mg·h^(-1),the pulsed microplasma source has the smallest physical dimensions which makes it possible to compact multiple such devices into a small volume for multiplied production rate.The matrix assembly source has the shortest development history,but already show an impressive deposition rate of~10 mg·h^(-1).At the end of the review,the possible routes for further throughput scale-up are envisaged.
