Janus film evaporator with improved light-trapping and gradient interfacial hydrophilicity toward sustainable solar-driven desalination and purification

•TiN/GO//GO Janus film is fabricated to realize the synergetic effect of high-efficient photothermal conversion and water transportation.•The gradient interfacial hydrophilicity of the Janus film increases heat utilization efficiency.•The Janus film can obtain high evaporation rate of 1.70 kg⋅m−2⋅h−1 for various non-conventional water resources under 1 solar illumination.•The Janus film exhibits excellent durability in a wide acid–base range (pH 2–11) and salinity range (0–250‰) over 30 cycles.•The outdoor device with Janus film demonstrated the daily water yield of 7.44 kg⋅m−2.