Raman spectra of single-wall carbon nanotubes ͑SWCNTs͒ were measured at different temperatures by varying the incident laser power. The elevated temperature of the SWCNTs and multiwall carbon nanotubes ͑MWCNTs͒ is confirmed to be due to the presence of impurities, defects, and disorder. The temperature coefficient of the frequency of the CC stretching mode E 2g ͑GM͒ and that of the radial breathing mode in the SWCNT were determined to be ϳϪ0.038 and ϳϪ0.013 cm Ϫ1 /K, respectively. It is found that the temperature coefficient of the GM in the SWCNT is larger than that of the MWCNT, highly oriented pyrolytic graphite, and the graphite. This is attributed to the structural characteristic of the SWCNT-a single tubular carbon sheet with smaller diameter.

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Amorphous/crystalline (a/c) hetero‐phase structures are considered as a class of efficient electrocatalysts for hydrogen evolution reaction (HER), but it remains a substantial challenge to obtain the specific phase by phase‐selective synthesis. In this work, a general route for the preparation of various heterogeneous aerogels (RuB, PtB, PdB, and RhB) consisting of amorphous and crystalline phases is presented through a controlled NaBH4 reduction method. The prepared a/c‐RuB aerogel exhibits better HER performance due to their desirable compositional and structural advantages such as more exposed active sites, optimized electronic structure, and interfacial synergistic effects. It requires only a low overpotential of 39 mV to reach a density of 10 mA cm−2 and also exhibits excellent stability. This work provides a new phase‐selective synthesis strategy for the design and development of advanced hetero‐phase electrocatalysts.