Large-scale fully printed“Lego Bricks”type wearable sweat sensor for physical activity monitoring

Wearable sweat sensors are becoming increasingly popular for their robust capabilities in non-invasive,dynamic,and continuous real-time monitoring of biological information.Real-time monitoring of large-scale samples is crucial for realizing intelligent health.A major bottleneck for enabling large-scale sweat elucidation is the fabrication of wearable sensors equipped with microfluidic devices and flexible electrodes in a cost-effective,homogeneous performance and rapid large-scale way.Herein,a“Screen+Wax”-printing technique was introduced to prepare these components and construct“Lego Bricks”type wearable sweat sensor sensor to monitor sweat Na^(+)and K^(+).Flexible electrode arrays and paper-based microfluidic layers(they act as building blocks)were fabricated on polyethylene terephthalate and paper surfaces,respectively,using screen printing and wax printing.Gold nanoparticles and Na^(+)/K^(+)ion-selective membranes were modified on the electrode surfaces by electrodeposition and drop coating,respectively.In this work,we highlight the excellent performance of the“Lego Bricks”type wearable sweat sensor in testing the Na^(+)and K^(+)imbalance of sweat from different body regions during exercise and,more significantly,to track the physical activity during prolonged exercise under different interventions.Furthermore,the prepared“Lego Bricks”wearable sweat ion electrochemical sensor is demonstrated to be capable of large-scale samples elucidation with outstanding performance and costeffectiveness,which is expected to deeply integrate sweat monitoring into physical activity,providing an important tool for intelligent health.

Structure-activity relationship of defective electrocatalysts for nitrogen fixation

Ammonia(NH_(3)), as an important chemical substance and clean energy carrier, plays an indispensable role in industrial and agricultural production. The electrocatalytic synthesis of NH+3 under mild conditions has attracted worldwide attention in the energy field due to its environmental friendliness and cost efficiency,but unsatisfactory NH_(3) yields and Faradaic efficiencies are restricting its development. The introduction of defect has been demonstrated as a feasible way to overcome the disadvantages of electrochemistry, as it can regulate the electronic structure and modulate coordination environment of electrocatalysts, which further create active sites and enhance nitrogen adsorption. In this regard, it is necessary to understand the effects of various types of defects on electrocatalysts based on the latest progress in the defect engineering for nitrogen reduction reaction(NRR). In this review, the concept, classifications, and characterization of defects as well as the approaches to create them in electrocatalysts are firstly discussed.Then, certain types of defects(vacancy, dopant, amorphism, edge/corner, and porousness) affecting the performances of various electrocatalysts are further described. Finally, the summary and challenges of electrocatalytic ammonia synthesis are proposed to design advanced electrocatalysts with high efficiency.

Chemo-Biocascade Reactions Enabled by Metal-Organic Framework Micro-Nanoreactor

The one-pot combination of biocatalytic and chemocatalytic reactions represents an economically and ecologically attractive concept in the emerging cascade processes for manufacturing.The mutual incompatibility of biocatalysis and chemocatalysis,however,usually causes the deactivation of catalysts,the mismatching of reaction dynamic,and further challenges their integration into concurrent chemo-biocascades.Herein,we have developed a convenient strategy to construct versatile functional metal-organic framework micro-nanoreactors(MOF-MNRs),which can realize not only the encapsulation and protection of biocatalysts but also the controllable transmission of substances and the mutual communication of the incompatible chemo-biosystems.Importantly,the MOFs serving as the shell of MNRs have the capability of enriching the chemocatalysts on the surface and improving the activity of the chemocatalysts to sufficiently match the optimum aqueous reaction system of biocatalysts,which greatly increase the efficiency in the combined concurrent chemo-biocatalysis.Such strategy of constructing MOF-MNRs provides a unique platform for connecting the“two worlds”of chemocatalysis and biocatalysis.