Hierarchical TiO2-coated metal-organic framework-derived carbon material for efficient co-generation of drinkable water and electricity

Abstract

Co-generation of drinkable water and electricity through interface solar steam generation process is gradually becoming the preferred strategy to solve the current energy shortage and freshwater resources crisis. Inspired by the biological channel structures, flexible carbonized TiO₂@Co-MOF nickel foam (CTCNF) based photothermal material with hierarchical nano-arrays structure is successfully fabricated on nickel foam surfaces by atomic layer deposition combined with an ingenious carbonization scheme, which endows CTCNF with combined excellent abilities including seawater desalination, evaporation-induced electricity generation, and wastewater purification, that is a three-in-one photothermal configuration. With the synergistic photothermal effect and hierarchical structure, CTCNF achieves a solar absorption efficiency of 93.65 %. Moreover, benefiting from its abundant oxygen- and nitrogen- containing functional groups, CTCNF not only possesses excellent hydrophilicity and salt resistance, but also reduces the water evaporation enthalpy (from 2453.3 J g⁻¹ to 1378.6 J g⁻¹). Importantly, combined with ingenious design of the evaporation device, CTCNF not only capture energy from environment during the evaporation process, with an evaporation rate of 3.60 kg m⁻² h⁻¹ and an evaporation efficiency of 109.9 % under 1 sun, but also obtains an open-circuit voltage (V_oc) of 151.15 mV. This enriches the design ideas of high-performance photothermal materials for efficient co-generation of drinkable water and electricity.