No abstract

Solar-driven interfacial steam generation is a promising technique for clean water production because it can minimize thermal loss by localizing solar-to-heat conversion at the air/liquid interface. Here we report an integrated solar evaporator by partially growing 2D polypyrrole microsheets within a melamine foam through chemical vapor polymerization. These microsheets can induce multiple light reflections within the foam, enable omnidirectional light absorption, provide abundant surfaces to promote heat transfer, and achieve spatially defined hydrophobicity to facilitate vapor escape. Meanwhile, the inherent hydrophilicity of the bottom part of the foam promotes spontaneous upward water transport and suppresses heat loss. The composite foam exhibits an excellent apparent evaporation rate of ∼2 kg/(m 2 •h) and solar-to-vapor efficiency of ∼91%. The combined advantages of large surface area, high efficiency, low cost, all-weather application, excellent durability, and scalable manufacturing make our integrated design promising for fabricating large-scale solar steam generation systems that are suitable for practical clean water production.

Herein, we showthat copper nanostructures,ifmade anisotropic,c an exhibit strong surface plasmon resonance comparable to that of gold and silver counterparts in the nearinfrared spectrum. Further,w ed emonstrate that ar obust confined seeded growth strategy allows the production of highquality samples with excellent control over their size, morphology,and plasmon resonance frequency.Asanexample,copper nanorods (CuNRs) are successfully grown in alimited space of preformed rod-shaped polymer nanocapsules,t herebya voiding the complex nucleation kinetics involved in the conventional synthesis.T he method is unique in that it enables the flexible control and fine-tuning of the aspect ratio and the plasmonic resonance.W ea lso showt he high efficiency and stability of the as-synthesized CuNRs in photothermal conversion and demonstrate their incorporation into nanocomposite polymer films that can be used as active components for constructing light-responsive actuators and microrobots.

The fast and reversible switching of plasmonic color holds great promise for many applications, while its realization has been mainly limited to solution phases, achieving solid‐state plasmonic color‐switching has remained a significant challenge owing to the lack of strategies in dynamically controlling the nanoparticle separation and their plasmonic coupling. Herein, we report a novel strategy to fabricate plasmonic color‐switchable silver nanoparticle (AgNP) films. Using poly(acrylic acid) (PAA) as the capping ligand and sodium borate as the salt, the borate hydrolyzes rapidly in response to moisture and produces OH− ions, which subsequently deprotonate the PAA on AgNPs, change the surface charge, and enable reversible tuning of the plasmonic coupling among adjacent AgNPs to exhibit plasmonic color‐switching. Such plasmonic films can be printed as high‐resolution invisible patterns, which can be readily revealed with high contrast by exposure to trace amounts of water vapor.

Advanced oxidation processes (AOPs) based on sulfate radicals (SO 4 ,À) suffer from low conversion rate of Fe(III) to Fe(II) and produce a large amount of iron sludge as waste. Herein, we show that by using MoO 2 as a cocatalyst, the rate of Fe(III)/Fe(II) cycling in PMS system accelerated significantly, with a reaction rate constant 50 times that of PMS/Fe(II) system. Our results showed outstanding removal efficiency (96%) of L-RhB in 10 min with extremely low concentration of Fe(II) (0.036 mM), outperforming most reported SO 4 ,À-based AOPs systems. Surface chemical analysis combined with density functional theory (DFT) calculation demonstrated that both Fe(III)/Fe(II) cycling and PMS activation occurred on the (110) crystal plane of MoO 2 , whereas the exposed active sites of Mo(IV) on MoO 2 surface were responsible for accelerating PMS activation. Considering its performance, and non-toxicity, using MoO 2 as a cocatalyst is a promising technique for large-scale practical environmental remediation.