In situ analysis of sweat provides a simple, convenient, costeffective, and noninvasive approach for the early diagnosis of physical illness in humans and is particularly useful in family care. In this study, a flexible and skin-attachable colorimetric sweat sensor for multiplexed analysis is developed using a simple, cost-effective, and convenient method. The obtained sweat sensor can be used to simultaneously detect glucose, lactate, urea, and pH value in sweat, as well as sweat loss and skin temperature. Only 2.5 μL of sweat is enough for the whole test, and the sweat loss and chemical-sensing results can be read out conveniently by naked eyes or a smartphone. In addition, body temperature can also be detected with an additional electrical circuit. Our sweat sensor provides a new, cost-effective, and convenient approach for in vitro diagnosis of multiple components in sweat, and the easy fabrication and cost-effectiveness make our sensor commercializable in the near future.

The reaction efficiency of reactants near plasmonic nanostructures can be enhanced significantly because of plasmonic effects. Herein, we propose that the catalytic activity of molecular catalysts near plasmonic nanostructures may also be enhanced dramatically. Based on this proposal, we develop a highly efficient and stable photocatalytic system for the hydrogen evolution reaction (HER) by compositing a molecular catalyst of cobalt porphyrin together with plasmonic gold nanoparticles, around which plasmonic effects of localized electromagnetic field, local heating, and enhanced hot carrier excitation exist. After optimization, the HER rate and turn-over frequency (TOF) reach 3.21 mol g−1 h−1 and 4650 h−1, respectively. In addition, the catalytic system remains stable after 45-hour catalytic cycles, and the system is catalytically stable after being illuminated for two weeks. The enhanced reaction efficiency is attributed to the excitation of localized surface plasmon resonance, particularly plasmon-generated hot carriers. These findings may pave a new and convenient way for developing plasmon-based photocatalysts with high efficiency and stability.

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Surface plasmons have received much attention in chemical reactions because of their high light-utilizing efficiency, high reaction rate, and mild reaction conditions. However, the potential of plasmonic photochemistry has not been fully exploited, mainly due to the limited lifetime of plasmongenerated hot carriers. Herein, using in situ Raman spectroscopy, we reveal that the coadsorption of p-hydroxythiophenol (PHTP) molecules significantly accelerates the plasmon-mediated decarboxylation reaction of p-mercaptobenzoic acid adsorbed on silver nanoparticles. The observed boosting of the decarboxylation reaction is attributed to the matched energy distribution of the plasmon-generated hot electrons to the lowest unoccupied molecular orbital (LUMO) level of the coadsorbed PHTP molecules. Our findings will help not only to deepen the understanding of the plasmon-mediated chemical reactions but also to fabricate highly efficient plasmonic catalysts conveniently and costeffectively.