Cu₃BiS₃/MXenes with Excellent Solar–Thermal Conversion for Continuous and Efficient Seawater Desalination

Abstract

Two-dimensional materials with unique physical and chemical properties have recently attracted widespread attention in the field of solar thermal conversion. However, affected by the Fresnel effect, traditional two-dimensional materials such as MXenes, graphene, transition metal disulfide often have relatively significant light reflection losses at the solid–liquid or gas interface. So how to improve the light absorption of the two-dimensional material performance has become a new challenge in photothermal conversion. Here, we use an improved thermal-injection method to uniformly grow Tricopper­(I) Bismuth Sulfide (Cu3BiS3, CBS) on the surface of Ti3C2 nanosheets in a nonaqueous polar solvent environment. A three-dimensional nanoflower-nanosheet structure CBS-Ti3C2 for photothermal conversion has been constructed successfully. Owing to the excellent photothermal performance of Cu3BiS3 in the near-infrared region, the good thermal conductivity of Ti3C2, and the unique porous structure of the composite material, the composite achieves broadband absorption of light (more than 90% in the visible light region, more than 80% in the near-infrared region), which optical model and finite element simulation have theoretically verified. The composite material has obtained higher solar-to-heat conversion performance than similar material systems, and the steady-state temperature can reach 62.3 °C under 1 sun incident light intensity. CBS-Ti3C2 is expected to become a light-absorbing layer material for solar vapor generation devices due to its excellent light-to-heat conversion performance and good material flexibility. It still guarantees a reasonably high steam generation rate (1.32 kg·m–2·h–1) even with a thinner material thickness (0.48 mg·cm–2) and a comprehensive conversion efficiency higher than 90%. Besides, CBS-Ti3C2 also exhibits the characteristics of resisting surface salt accumulation, which is conducive to maintaining the long-lasting photothermal seawater evaporation process. The material’s electronic structure and the charge transfer process of the heterojunction interface have been studied with the first-principles calculation. The high light absorption performance and good thermal conductivity of the composite material are theoretically explained and supported.

MXene-Coated Membranes for Autonomous Solar-Driven Desalination

“…They are defined by the general formula M n +1 X n T x , 38 , 42 where T x represents the surface-terminated species (−F, −OH, or −O). 43 , 44 Owing to their unique properties, MXene nanosheets, particularly Ti 3 C 2 T x , have been employed as a photothermal coating for MD membranes, 45 benefiting from the pronounced surface plasmon (SP) oscillations at the surface of the nanosheets. 46 , 47 In principle, upon the light illumination of MXene membranes at wavelengths in resonance with these SPs, the temperature gradient generated across the membrane surges due to the intrinsic SP-assisted light-to-heat conversion.…”

First-Principles Study on the Half-Metallicity of New MXene Materials Nd2NT2 (T = OH, O, S, F, Cl, and Br)

“…Tan et al studied the strain piezoelectric coefficient of La 2 CO 2 , a lanthanide MXene material, under axial strain. They reported that strain piezoelectric coefficient of this material is up to 22.32 pm/V, which is substantially higher than that of other known piezoelectric materials, such as Sc 2 CO 2 , Y 2 CO 2 , BN, GaAs, and AlSb ( Chen et al, 2021 ; Wang et al, 2021b ). Bai et al reported that the semiconductor MXene material Lu 2 CT 2 (T = F, OH) has a low work function and a carrier mobility of about 105 cm 2 /V at room temperature ( Zhang et al, 2021 ).…”

Advancements in Solar Desalination of Seawater by Various Ti3C2 MXene Based Morphologies for Freshwater Generation: A Review

“…In this manner, we can improve the incident light absorption capacity by the photothermal 2D materials. For this, Wang et al [60] developed the Cu 3 BiS 3 (CBS) on Ti 3 C 2 MXene nanosheets (0.2 g) for the first time via the thermal-injection method in the ratio of 1:1 (CBS-Ti 3 C 2 ). Later, this composition at different loadings (0.12, 0.24, 0.48, and 0.60 mg cm −2 ) was placed on a hydrophilic porous filter membrane (PVDF) and vacuum dried overnight.…”

“…Similar to the PVDF membrane interfacial interaction with the Ti 3 C 2 MXene [39,60,61], another study on the Ti 3 C 2 /PVDF membrane was explored by Peng et al [62]. They revealed an efficient air-water interface during solar desalination.…”