Integrating nitrogen-doped graphitic carbon with Au nanoparticles for excellent solar energy absorption properties

A novel excellent carbon-H2O nanofluid, nitrogen-doped graphitic carbon, has been discovered and prepared by using a facile metal-organic frameworks (MOFs) derived synthesis method. The obtained ZIF-8 (ZIF denotes zeolitic imidazolate framework) derived nitrogen-doped graphitic carbon (ZNG) analogs have high specific surface area of 580.2 m(2) g(-1) and show broad band absorption across the visible and near-infrared region. Au nanoparticles with the size of 2-5 nm are facilely and successfully deposited on the surface of nitrogen-doped graphitic carbon (Au/ZNG) via an impregnation-reduction method. The photothermal conversion tests indicate that both ZNG-H2O and Au/ZNG-H2O nanofluids show better photo-thermal performance and more awesome dispersion stability in water than conventional carbon nanofluids such as graphene and nitrogen-doped carbon nanotubes. Just as expected, Au/ZNG nanofluid shows obvious enhancement in photo-thermal performance due to the synergistic effect of the localized surface plasmon resonance (LSPR) Au nanoparticles and ZNG. This novel ZNG/water nanofluid is very attractive in working fluids for direct absorption solar collectors.