Optimization and Parameter Investigation of the Planar Photocatalytic Microreactor.

The microreactor could break the limitation of mass transfer and photon transmission in photocatalysis. Through a facile assembly method, a planar photocatalytic microreactor was constructed to fit most of the photocatalysts regardless of their strict preparation method. This microreactor exhibits a 2.41-fold efficiency compared to a bulk reactor. Parameters that affect the photocatalytic performance were discussed in detail by experiment and calculation. The diffusion rate is the main bottleneck in a planar microreactor under a laminar flow. The microreactor with lower height shows higher efficiency owing to faster mass transfer, while the length and width affect slightly. Elevating the light power density provides a diminishing benefit. Faster flow speed reduces the apparent degradation percent but increases the chemical reaction rate, in fact. The reaction rate increases to 9.31 times by reducing the height from 500 to 100 µm and grows another 1.76 times by adding the flow speed from 10 to 40 mL/h. This work illustrates the influence of parameters on planar photocatalytic microreactors and offers a promising prospect for large-volume photocatalytic water treatment.

Efficient liquid phase photothermal catalysis realized by Ag2O/Bi4O5I2via heat-localization in a microreactor.

By constructing a Ag2O/Bi4O5I2 p-n heterojunction and applying a heat-localization microreactor, efficient photocatalysis enhanced by both photoinduced carrier separation and the photothermal effect was realized. This work focuses on the utilization of near-infrared light to broaden the absorption spectrum and accelerate the transportation of carriers. Through the production and localization of heat, it provides a novel thought for full-spectrum photocatalysis.

Elevating the Photocatalytic Performance of BiOCl by Promoting Light Utilization: From Co doping to the Microreactor.

Owing to its unique layered structure, BiOCl demonstrates high photocatalytic activity. However, its wide bandgap hinders the absorption of visible light. Doping modification is an effective method to expand the light absorption edge of photocatalysts by creating a doping energy level within the bandgap. Herein, Co as a variable valence element was used to dope the BiOCl nanosheets through a simple hydrothermal approach. As a result, the absorption edge of Co-BiOCl extends to the visible light region, and the photocatalytic performance was enhanced by 3.02 times. To overcome the shortcoming of photons being consumed easily in the bulk reactor, a planar microreactor was introduced to reduce the attenuation of light and accelerate the mass transfer. By comparison to the bulk reactor, a maximum of 15.3-fold additional activity promotion emerged. This work combines doping modification and reactor improvement to realize highly efficient photocatalysis in practical application.

Infrared light induced sustainable enhancement of photocatalytic efficiency by thermoelectric effect.

Hindering the recombination of photoinduced electron-hole pairs is of significance for enhancing photocatalytic performance. Applying a voltage to separate carriers offers an option to realize it. Thermoelectric materials own the ability to continuously sustain a voltage when a temperature difference exists between its two sides. However, maintaining the thermoelectric effect without wasting additional energy remains a challenge. Herein, a C3N4/Polyaniline/Poly(vinylidene fluoride) cilia array was fabricated to reach efficient photocatalysis through thermoelectric effect and photothermal effect. The cilia array structure offers more than 40% of light absorbance compared to the film. Hence, the infrared light in sunlight, which was usually omitted in photocatalysis, was transformed into heat. Through the unique design which draws upon the huge difference in thermal conductivity of air and water, a temperature gap was formed between the top and bottom sides of the cilia array by half-submerging it in water. Therefore, the photocatalytic efficiency was improved by 84.4%. This work achieves an energy-saving method to enhance photocatalytic performance by activating thermoelectric effect through infrared light, shedding light on the application of multi-modes enhanced photocatalysis.

Using Li(+) as the electrochemical messenger to fabricate an aqueous rechargeable Zn-Cu battery.

We propose an aqueous rechargeable Zn-Cu Daniell-type battery. In this system, Li(+) prefers to conduct currents rather than react with the electrodes, while the Zn-Cu electrode couples engage in their electrochemical reactions free from conducting currents. Here Li(+) performs like a messenger and thus could be called the electrochemical messenger.

Electrocatalytic activity of PtAu/C catalysts for glycerol oxidation.

The electrocatalytic oxidation of glycerol on PtAu/C catalysts has been investigated by cyclic voltammetry. PtAu bimetallic nanoparticles are prepared by chemical reduction. Carbon-supported PtAu catalysts are found to exhibit high electrocatalytic activity for the oxidation of glycerol in alkaline solution in terms of oxidation potential and current density as well as stability, and PtAu/C catalysts with different Pt:Au composition ratios show no much difference in catalytic activity. In acidic solution, PtAu/C catalysts exhibit similar to Pt/C catalysts in activity, but the advantage of the PtAu/C catalysts in terms of per unit mass of platinum is still obvious. The PtAu/C catalysts, in a wide Pt:Au ratio range, show a remarkable enhancement in the mass specific activity of platinum with decreasing platinum content in both alkaline and acidic solutions. This is of significance for reducing the usage of platinum and indicates that though platinum acts as main active sites, gold also plays an important role in the function of PtAu/C catalysts.