Investigation of thermal conductivity enhancement of water-based graphene and graphene/MXene nanofluids

•MXene can effectively improve the dispersion stability of GR nanofluids.•The nanofluid with 2 wt% GR obtains maximum thermal conductivity enhancement of 65.34%.•The viscosity significantly decreases with an increase in MXene content.•The temperature at monitoring point decreases by 9.19 ℃ with 2.0 wt% GR relative to water.•The heat transfer efficiency of GR/MXene and GR nanofluids is almost the same.