A Hybrid Artificial Photocatalysis System Splits Atmospheric Water for Simultaneous Dehumidification and Power Generation

Abstract

A new approach for artificial photocatalysis of electrical generation directly from atmospheric water is reported. A hybrid system comprising a hydrogel incorporated with Cu2O and BaTiO3 nanoparticles is developed, wherein the Cu2O is designed to expose two different crystal planes, namely (100) and (111). These planes exhibit different surface potentials and form a polarization electric field of 2.3 kV cm−1 that acts on a ferroelectric dipole. With the help of this electric field, the dipole is redirected for aiding in positive and negative polarizations with (100) and (111) planes, then boosting water reduction and oxidation kinetics separately at (100) and (111) planes. Additonally, zinc‐/cobalt‐based superhygroscopic hydrogels serve as a water‐capturing “hand” to harness humidity from the ambient environment. The integrated hydrogel–Cu2O@BaTiO3 hybrid is used to dehumidify air, which can split 36.5 mg of water by employing only 150 mg hydrogel and simultaneously generate a photocurrent of 224.3 µA cm−2 under 10 mW cm−2 illumination.

Tuning Electronic Structure of 2D In2S3 via P Doping and Size Controlling Toward Efficient Photoelectrochemical Water Oxidation

“…[41] The higher E F could induce the accumulation of positive charges in the depletion region at the surface of P-In 2 S 3 (s), in other words, hybridized state could broaden the depletion width, which generates built-in potential and bends the band structure upward, and therefore the dynamic of hole's transfer to surface is reinforced. [4] Furthermore, P-In 2 S 3 (s) clarifies the highest incident phototo-electron conversion efficiencies (IPCE), which is in a good agreement with the UV-vis absorption spectra and consistent with the enhanced photocurrent (Figure 8a). After the 2 h test, the activity of P-In 2 S 3 (s) retains 92% of its initial photocurrent, whereas only 65% and 49% of the activity was maintained on the pristine In 2 S 3 (s) and In 2 S 3 , respectively, implying the perfect photostability after P doping (Figure 8b).…”

“…[ 41 ] The higher E F could induce the accumulation of positive charges in the depletion region at the surface of P‐In 2 S 3 (s), in other words, hybridized state could broaden the depletion width, which generates built‐in potential and bends the band structure upward, and therefore the dynamic of hole's transfer to surface is reinforced. [ 4 ]…”

“…[ 1–3 ] In a complete PEC cycle, the water oxidation on photoanodes is more energetically demanding and rate limiting due to the sluggish four electrons transfer process. [ 4 ] Two‐dimensional (2D) materials present the advantages of a short exciton diffusion distance and a thickness less than the width of the space charge region at solid/liquid interfaces, thus potentially serve as the excellent photoanodes. [ 5,6 ] Indium sulfide (In 2 S 3 ) is a broad‐spectral 2D material with ordered vacancy spinel‐like structure, the sulfide anions are closely packed in layers, with octahedral‐coordinated In cations present within the layers, and tetrahedral‐coordinated In cations between them.…”

A Moisture‐Hungry Copper Complex Harvesting Air Moisture for Potable Water and Autonomous Urban Agriculture

“…Atmospheric humidity, a huge source of freshwater, has remained relatively unexplored. [ 12 ] Amount of atmospheric water is equivalent to 5.2 billion Olympic‐sized pools or more than halved the size of Baltic Sea. [ 13,14 ] The atmospheric water harvesting technology opens up a self‐sustaining source of freshwater that can potentially support millions of drinking needs and agriculture.…”

Structure Architecting for Salt‐Rejecting Solar Interfacial Desalination to Achieve High‐Performance Evaporation With In Situ Energy Generation

“…[ 156 ] By combining with hydroscopic materials such as the hydrogel demonstrated by Tan and co‐workers recently, the generated water vapor was split into hydrogen and oxygen in an hybrid artificial photocatalysis system. [ 157,158 ] In this view, although there seems to be not much margin for improvement of conversion efficiency of solar evaporation, it has exhibited promising potential in playing a role to facilitate interesting and constructive interdisciplinary studies between different energy application fields. In addition to the interesting interdisciplinary combinations with solar evaporation, practical feasibility of these integrated systems should also command our attention.…”