MXene/CdS photothermal–photocatalytic hydrogels for efficient solar water evaporation and synergistic degradation of VOC

Abstract

Solar-driven interfacial water evaporation technology (SIET) is an emerging method for achieving sustainable production of clean water. Most available studies have focused on improving the evaporation efficiency of water, while less attention has been paid to the enrichment of evaporated organic contaminants, especially volatile organic compounds (VOCs) in distilled water, which is one of the key challenges in SIET. Herein, Ti₃C₂ MXene/CdS (MC) nanomaterials were synthesized by acid etching and hydrothermal methods, and MC composite hydrogels (MCHs) with synergistic effects of photothermal evaporation and photocatalysis were successfully prepared by crosslinking foaming polymerization. The water evaporation rate of optimal MCHs was 1.80 kg m⁻² h⁻¹ and the photothermal conversion efficiency of 82.80% could be achieved under one sun irradiation. Most importantly, MCHs significantly degraded a variety of organic contaminants in wastewater, among which the photodegradation rate of a typical VOC (phenol) was 85.12%, and the antibiotic metronidazole was completely removed. This research inferred that the MC hydrogels could be the promising synergistic photothermal evaporation and photocatalytic materials, providing a potential pathway for sustainable clean water production in the SIET field.