posted on 2023-12-30, 14:29authored byDong Xia, Jamie Mannering, Peng Huang, Yifei Xu, Qun Li, Heng Li, Yi Qin, Alexander N. Kulak, Robert Menzel
Flash Joule heating
of highly porous graphene oxide (GO) aerogel
monoliths to ultrahigh temperatures is exploited as a low carbon footprint
technology to engineer functional aerogel materials. Aerogel Joule
heating to up to 3000 K is demonstrated for the first time, with fast
heating kinetics (∼300 K·min–1), enabling
rapid and energy-efficient flash heating treatments. The wide applicability
of ultrahigh-temperature flash Joule heating is exploited in a range
of material fabrication challenges. Ultrahigh-temperature Joule heating
is used for rapid graphitic annealing of hydrothermal GO aerogels
at fast time scales (30–300 s) and substantially reduced energy
costs. Flash aerogel heating to ultrahigh temperatures is exploited
for the in situ synthesis of ultrafine nanoparticles (Pt, Cu, and
MoO2) embedded within the hybrid aerogel structure. The
shockwave heating approach enables high through-volume uniformity
of the formed nanoparticles, while nanoparticle size can be readily
tuned through controlling Joule-heating durations between 1 and 10
s. As such, the ultrahigh-temperature Joule-heating approach introduced
here has important implications for a wide variety of applications
for graphene-based aerogels, including 3D thermoelectric materials,
extreme temperature sensors, and aerogel catalysts in flow (electro)chemistry.