Vertical graphene nanowalls (VGNs) with excellent heat-transfer properties are promising to be applied in the thermal management of electronic devices. However, high growth temperature makes VGNs unable to be directly prepared on semiconductors and polymers, which limits the practical application of VGNs. In this work, the near room-temperature growth of VGNs was realized by utilizing the hot filament chemical vapor deposition method. Catalytic tantalum (Ta) filaments promote the decomposition of acetylene at ∼1600 °C. Density functional theory calculations proved that C2H* was the main active carbon cluster during VGN growth. The restricted diffusion of C2H* clusters induced the vertical growth of graphene nanoflakes on various substrates below 150 °C. The direct growth of VGNs successfully realized the excellent interfacial contact, and the thermal contact resistance could reach 3.39 × 10–9 m2·K·W–1. The temperature of electronic chips had a 6.7 °C reduction by utilizing directly prepared VGNs instead of thermal conductive tape as thermal-interface materials, indicating the great potential of VGNs to be directly prepared on electronic devices for thermal management.

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Electromagnetic interference (EMI) shielding materials with low thickness and improved EMI shielding performance are highly required. Herein, by utilizing the plasma-enhanced chemical vapor deposition (PECVD) method with the optimized source power of the plasma generator, vertical graphene nanowalls (VGNs) with a relatively rapid growth rate of ∼5 μm•h −1 were prepared on substrates. The porous conductive VGNs exhibited preferable EMI shielding performance. In a frequency range of 8.2−12.4 GHz, the EMI shielding effectiveness (SE) value of VGNs with a thickness of 47.5 μm could reach 26.2 dB. In addition, VGNs with controllable thickness were also synthesized on Cu foam substrates. The combination of VGNs and Cu foam significantly improved the porosity and interfacial coupling effect of the composites. By growing VGNs with a thickness of ∼20 μm on the Cu foam, their absorption efficiency got largely enhanced by 13.8 dB (32.2%) compared with the pristine Cu foam. Subsequently, the total EMI SE of the VGNs/Cu foam composite films got enhanced by 13.5 dB (20.8%) compared with the pristine Cu foam. The VGNs and their composites with preferable EMI shielding performance establish potential for practical applications in EMI shielding.

The non-catalyst preparation of high-quality Vertical graphene nanowalls (VGN) and graphene-based high output power hydrovoltaic effect power generation devices have always been difficult to achieve. In this work, we successfully...

In order to obtain the functional relationship of gas content and gas pressure, and to accurately calculate the two values which fitting the characteristics of coal seam, the destruction coefficient