Enhanced Photothermal Conversion in Res2/Bi2se3 Nanoflowers for Solar-Driven Thermoelectric Power Generation and Water Evaporation

Abstract

The development of high-performance photothermal materials and the elucidation of the underlying physical mechanisms are of paramount importance for solar-driven water evaporation and thermoelectric power generation. In this study, we introduce a novel composite material consisting of ReS2/Bi2Se3 nanoflowers, synthesized via a facile hydrothermal method. These nanoflowers, with Bi2Se3 nanosheets grown on the ReS2 nanosheets, exhibit excellent photothermal conversion capabilities. This is attributed to the synergistic effects of the topological surface states, lattice vibrations, and charge transfer properties within the hybrids. The integration of ReS2/Bi2Se3 into a cotton substrate results in a photothermal membrane with superior sunlight absorption exceeding 93%, along with outstanding hydrophilicity and photothermal conversion efficiency. The membrane facilitates a remarkable thermoelectric power output of 2.67 W cm-2, a water evaporation rate of 1.84 kg m-2 h-1, coupled with an evaporation efficiency of 97.52%. Furthermore, the membrane demonstrates a stable evaporation rate under different pH conditions and in 25 wt% saline solution. The evaporation of seawater and solutions containing heavy metal ions reveal the membrane’s potential for water production and industrial wastewater purification. Additionally, the ReS2/Bi2Se3 membrane can generate 7.34 kg/m2 of purified water under natural sunlight irradiation in 9 h. This research gives an inspiration on the design of photothermal materials based on topological insulators for efficient solar-driven energy conversion.

Keywords: semiconductor heterojunction, topological surface state, photothermal conversion, solar water evaporation, photothermal-electric generation