Construction of 2D lamellar membrane for a combination of photocatalytic hydrogen evolution and photothermal water evaporation

Authors：Weiming Zhou, Hongqiang Huang, Yiting Wu, JunWang, Xingtao Xu, Liwei Wang*, Chong Wang*, Yusuke Yamauchi* and Zhanhui Yuan*

Abstract: Solar energy can help solve the energy and water shortage crisis. Developing a single material that can exhibit both photocatalytic hydrogen evolution (PHE) and photothermal water evaporation (PWE) represents a new concept to simultaneously realize green energy and fresh water supply. In this study, a series of 2D lamellar membranes (2DLMs) based on a conventional semiconductor BiOCl nanosheet is designed as an ensemble, and its combined application for PHE and PWE is explored, in which cellulose nanofibers (CNFs), carbon nanotubes (CNTs), and a self-assembly of CNF@CNT are used as 1D materials. The PHE and PWE efficiencies are closely related to the conversion of solar energy and the state of the water molecules. Owing to the high light-to-thermal conversion, enhanced water transfer, and the low evaporation enthalpy of confined water, a composite made of BiOCl and CNF@CNT 2DLM (BOC-CNF@CNT) could rapidly reach a surface temperature of 46.6 °C, with its PWE rate reaching up to 2.05 kg·m⁻²·h⁻¹. Moreover, owing to the high photogenerated carrier transport, strong photothermal effect, and the action of confined water, the PHE rate of BOC-CNF@CNT is 1.99-fold that of the composite made of BiOCl and CNF 2DLM (BOC-CNF) and 1.42-fold that of the composite made of BiOCl and CNT 2DLM (BOC-CNT). This work provides a new and effective strategy for a comprehensive utilization of solar energy to simultaneously produce clean hydrogen and fresh water.

Keywords: Lamellar membranePhotocatalyst hydrogen evolutionPhotothermal water evaporationCellulose nanofibersCarbon nanotubes

DOI:https://doi.org/10.1016/j.cej.2023.144395