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.
First-row (3d) transition-metal catalysts, such as bimetallic Ni-Co, represent an emerging class of electrocatalysts for HER, but they usually suffer from a large overpotential significantly above thermodynamic demands. Here, we doped NiCo catalyst with non3d metals molybdenum (Mo) for improvement in catalyzing the hydrogen evolution reaction. The ternary catalyst was readily obtained by a one-pot process via the sequential electrodeposition of Ni, Co, and Mo precursors on titanium (Ti) support. By tailing the deposition conditions, we fabricated NiCoMo catalysts with three-dimensional dendritic structures, exhibiting large amounts of electrochemically active sites. To attain the benchmark HER current density of -10 mA cm, an overpotential of ∼132 mV is required in 0.1 M KOH for the Mo-doped NiCo (5 atom % Mo in bath), and they produced the decreasing in Tafel slope of ∼108 mV decade exceeding those of binary NiCo alloy catalysts and other contents of Mo doping. In a synergistic effect, dopant incorporation of Mo element may provide near-optimal adsorption energies for HER intermediates promoting the process of water dissociation and hydrogen intermediates production and binding into molecular hydrogen.
Solar-driven interfacial steam generation is emerging as a green and sustainable technology for potential applications in sterilization, desalination, and water purification. Despite the encouraging progress to date, the solar absorbers of the interfacial steam generators generally are composed of costly and/or delicate nanostructures made from metal particles or semiconductor materials, which partially hinder their mass production for practical applications. Herein, the biomass Enteromorpha prolifera was successfully recycled to construct four biochar-based solar absorbers via a set of processing methods. The hydrophilic, hierarchically porous, and microtubular nanostructures of the carbonized E. prolifera contribute to synergistically efficient water pumping and steam generation of the solar absorbers. Inspired by the natural transpiration of trees, the two-dimensional interfacial steam generators based on the four solar absorbers attain good water evaporation rates of 1.1− 1.3 kg m −2 h −1 and high photothermal conversion efficiencies of 80−84% under one sun. Specifically, the performance is among the best-performing solar steam generators constructed via biochar-based solar absorbers. The indoor and outdoor experiments demonstrate the first example of using green tide as a sustainable source for biochar-based solar absorbers and realizing costefficient and high-performance steam generation and clean water production.
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