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Efficient electron transfer from photosensitizer to catalytic sites is crucial for effective artificial photosynthesis, yet it remains a significant challenge. Herein, it is reported that simple fluorination of the organic linkers in the MIL‐101(Fe) photocatalyst results in a remarkable threefold increase in the photocatalytic CO2‐to‐CO conversion rate (688 µmol g−1 h−1) compared to the pristine counterpart (230 µmol g−1 h−1). It is unveiled that, instead of directly modifying the electron structure of MIL‐101(Fe), the fluorinated linkers enhance the interaction between the discrete photocatalyst and photosensitizer ([Ru(bpy)3]2+, bpy = 2,2'‐bipyridine) via hydrogen bonding, thereby facilitating their intermolecular electron transfer. Most importantly, it is also demonstrated that this performance boosting strategy can be applied to other Fe‐based metal–organic frameworks (MOFs) photocatalysts such as MIL‐53(Fe) and MIL‐88(Fe). The present work not only underscores the fluorination of organic linkers as a generic promising approach to enhance the photocatalytic performance of MOF‐based catalysts, but also holds significant implications for photosynthesis and catalytic processes reliant on intermolecular electron transfer as an important step. [ABSTRACT FROM AUTHOR]

[Display omitted] • Wood-based Al-air batteries designed for miniaturized power sources. • Photothermal evaporation drives electrolyte flow through porous electrodes. • Integration of 3D wood-based microfluidics with solar energy utilization. • Impressive peak power density of 230 mW cm−3. • Stable discharge for over 11 h, ideal for long-lasting power supply. Capillary microfluidics on porous substrates emerges as an innovative platform for constructing miniaturized electronics. However, maintaining a steady flow within microfluidics remains challenging, thus limiting their practical applications. Inspired by plant transpiration, this work presents a novel wood-based microfluidic Al-air battery (μAAB) configuration driven by a photothermal evaporator (biomimetic "leaf"). Except for the Al anode, the μAAB features an all-wood design, utilizing the well-aligned microchannels of the natural wood for electrolyte transportation, partially charred wood as photothermal evaporator for flow regulating, and wood-derived self-standing carbon cathode for the oxygen reduction reaction. These components are assembled through mortise-and-tenon joints, and the resulting μAAB exhibits a remarkable peak power density of 230 mW cm−3. The superior performance stems from the boosted mass transfer, maximized electrochemical interface and minimized depletion boundary layer provided by the 3D channeled structure of the wood-derived cathode. A steady discharge for over 11 h (200 mA cm−3) is obtained via the continuous electrolyte flow which is facilitated by the photothermal evaporator in the μAAB. This work not only presents a novel concept for miniaturized microfluidic power sources but also highlights the potential of 3D wood-based microfluidics combined with solar energy utilization. [ABSTRACT FROM AUTHOR]

The key to fully leveraging the potential of the electrochemical CO2 reduction reaction (CO2RR) to achieve a sustainable solar‐power‐based economy is the development of high‐performance electrocatalysts. The development process relies heavily on trial and error methods due to poor mechanistic understanding of the reaction. Demonstrated here is that ionic liquids (ILs) can be employed as a chemical trapping agent to probe CO2RR mechanistic pathways. This method is implemented by introducing a small amount of an IL ([BMIm][NTf2]) to a copper foam catalyst, on which a wide range of CO2RR products, including formate, CO, alcohols, and hydrocarbons, can be produced. The IL can selectively suppress the formation of ethylene, ethanol and n‐propanol while having little impact on others. Thus, reaction networks leading to various products can be disentangled. The results shed new light on the mechanistic understanding of the CO2RR, and provide guidelines for modulating the CO2RR properties. Chemical trapping using an IL adds to the toolbox to deduce the mechanistic understanding of electrocatalysis and could be applied to other reactions as well. [ABSTRACT FROM AUTHOR]

Paper-based microfluidics is characteristic of fluid transportation through spontaneous capillary action of paper and has exhibited great promise for a variety of applications especially for sensing. Furthermore, paper-based microfluidics enables the design of miniaturized electrochemical devices to be applied in the energy sector, which is especially attractive for the rapid growing market of small size disposable electronics. This review gives a brief summary on the basics of paper chemistry and capillary-driven microfluidic behavior, and highlights recent advances of paper-based microfluidics in developing electrochemical sensing devices and miniaturized energy storage/conversion devices. Their structural features, working principles and exemplary applications are comprehensively elaborated and discussed. Additionally, this review also points out the existing challenges and future opportunities of paper-based microfluidic electronics., Competing Interests: The authors declare no conflict of interest., (©2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)