In the present study, a hollow honeycomb structured (HHS) pattern is fabricated using fusion deposition modelling and filled with different natural fibres namely sugarcane (SC) and cotton sponge (CS). It is then called HHS-SC and HHS-CS interfacial solar evaporators. In addition, reduced graphene oxide (rGO) nanomaterial is coated on the top evaporative surface of the developed evaporators to investigate the performance of interfacial solar steam generation (ISSG). During experimentation, HHS-CS/rGO evaporator exhibits better performance than HHS-SC/rGO evaporator. At indoor conditions, mass loss of water (MW), evaporation flux (EF) and evaporation efficiency (EE) of the HHS-CS/rGO evaporator are 2.0 g, 3.493 kg/m2h and 84.04 % respectively. Consequently, the MW, EF and EE are 6.2 g, 1.35 kg/m2h and 61.29 % respectively at outdoor conditions. Results show that (i) the reduction in the size of porosity and improved capillary action of CS (ii) the super hydrophilicity nature of CS increases the water transportation (iii) the poor thermal conductivity of CS (iv) the higher thermal conductivity of rGO aids in trapping the sunlight. The stability and repeatability of the HHS-CS/rGO evaporator are investigated and found to be excellent for 8 repetitive cycles. Additionally, the prepared interfacial solar evaporator results better performance in dye molecule separation and salt water purification and hence, this can be recommended for commercial applications.