Cover illustration
(Hongtao Xie, Qin Geng, Xiaoyue Liu, Jian Mao, pp. 376–383)
Rational design of highly efficient electrocatalysts for oxygen evolution reaction (OER) is critical for sustainable energy conversion. Herein, a novel bijunction CoS/CeO2 OER electrocatalyst grown on carbon cloth is prepared through electrodeposition. Such a CoS/CeO2/CC electrocatalyst exhibits outstanding OER catalytic activity with a low overpotential of 311 mV at 10 mA•cm−2
[Detail] ...
Compared to conventional hyperthermia that is limited by low selectivity and severe side effects, nano-enabled hyperthermia yields great potentials to tackle these limitations for cancer treatment. Another major advance is the observation of immunological responses associated with nano-enabled hyperthermia, which introduces a new avenue, allowing a potential paradigm shift from the acutely effective and cytotoxicity-centric response to the next-phase discovery, i.e., long-lasting and/or systemic anti-tumor immunity. This perspective first discusses the temperature-gradient and the spatially-structured immunological landscape in solid tumors receiving nano-enabled hyperthermia. This includes the discussion about underlying mechanism such as immunogenic cell death, which initiates a profound immunological chain reaction. In order to propagate the immune activation as a viable therapeutic principle, we further discussed the tumor type-specific complexity in the immunological tumor microenvironment, including the creative design of nano-enabled combination therapy to synergize with nano-enabled hyperthermia.
The tumor microenvironment features over-expressed hydrogen peroxide (H2O2). Thus, versatile therapeutic strategies based on H2O2 as a reaction substrate to generate hydroxyl radical (•OH) have been used as a prospective therapeutic method to boost anticancer efficiency. However, the limited Fenton catalysts and insufficient endogenous H2O2 content in tumor sites greatly hinder •OH production, failing to achieve the desired therapeutic effect. Therefore, supplying Fenton catalysts and elevating H2O2 levels into cancer cells are effective strategies to improve •OH generation. These therapeutic strategies are systematically discussed in this review. Furthermore, the challenges and future developments of hydroxyl radical-involved cancer therapy are discussed to improve therapeutic efficacy.
The platinum nanowires have been verified to be a promising catalyst to promote the performance of proton exchange membrane fuel cells. In this paper, accurately controlled growth of nanowires in a carbon matrix is achieved for reducing Pt loading. The effects of formic acid concentration and reaction temperature on the morphology and size of the Pt nanowires, as well as their electrochemical performances in a single cell, are investigated. The results showed that the increase in the formic acid concentration results in a volcano trend with the length of Pt nanowires. With increasing reduction temperature, the diameter of Pt nanowires increases while Pt particles evolve from one-dimensional to zero-dimensional up to 40 °C. A mechanism of the Pt nanowires growth is proposed. The optimized Pt nanowires electrode exhibits a power density (based on electrochemical active surface area) 79% higher than conventional Pt/C one. The control strategy obtained contributes to the design and control of novel nanostructures in nano-synthesis and catalyst applications.
To realize renewable energy conversion, it is important to develop low-cost and high-efficiency electrocatalyst for oxygen evolution reaction. In this communication, a novel bijunction CoS/CeO2 electrocatalyst grown on carbon cloth is prepared by the interface engineering. The interface engineering of CoS and CeO2 facilitates a rapid charge transfer from CeO2 to CoS. Such an electrocatalyst exhibits outstanding electrocatalytic activity with a low overpotential of 311 mV at 10 mA∙cm−2 and low Tafel slope of 76.2 mV∙dec–1, and is superior to that of CoS (372 mV) and CeO2 (530 mV) counterparts. And it has long-term durability under alkaline media.
Alkylation of benzene to value-added, high octane number and low toxic toluene and xylenes provides a way to lower benzene content in gasoline pool, and is hence a method to promote fuel quality. On the other hand, CO2 accumulation in the atmosphere causes global warming and requires effective route for its valorization. Utilization of CO2 as a carbon source for benzene alkylation could achieve both goals. Herein, alkylation of benzene with CO2 and H2 was realized by a series of low-cost bifunctional catalysts containing zinc/titanium oxides (Zn/Ti oxides) and HZSM-5 molecular sieves in a fixed-bed reactor. By regulating and controlling oxygen vacancies of Zn/Ti oxides and the acidities of HZSM-5, benzene conversion and CO2 conversion reached 28.7% and 29.9% respectively, along with a total selectivity of toluene and xylene higher than 90%. In this process, more than 25% CO2 was effectively utilized and incorporated into the target products. Moreover, the mechanism of the reaction was analyzed and the course was simultaneously traced. CO2 was transformed into methanol firstly, and then methanol reacted with benzene generating toluene and xylene. The innovation provides a new method for upgrading of fuels and upcycling the emissions of CO2, which is of great environmental and economic benefits.
The catalytic hydrogenation of carboxylic acid to alcohols is one of the important strategies for the conversion of biomass. Herein, a series of Ni-doped PtSn catalysts were prepared, characterized and studied in the hydrogenation of acetic acid. The Ni dopant has a strong interaction with Pt, which promotes the hydrogen adsorption, providing an activated hydrogen-rich environment for the hydrogenation. Meanwhile, the presence of Ni also improves the Pt dispersion, giving more accessible active sites for hydrogen activation. The cooperation of Pt and Ni significantly promotes the catalytic activity of the hydrogenation of acetic acid to ethanol. As a result, the catalyst with 0.1% Ni exhibits the best reaction activity, and its space time yield is twice as that of the PtSn/SiO2 catalyst. It provides a meaningful instruction on the catalyst design for the carboxylic acid hydrogenation.
Composite materials have elicited much interest because of their superior performance in the removal of toxic and radioactive uranyl ions from aqueous solutions. With polyethyleneimine as a functional group, carboxylated chitosan as a matrix, and oxidizing activated carbon as a nanofiller, this study synthesized a novel environment-friendly polyethylenimine-functionalized carboxylated chitosan/oxidized activated charcoal (PCO) biocomposite with a unique three-dimensional porous structure. PCO was synthesized through an easy chemical cross-linking method. Detailed characterization certified the formation of the unique three-dimensional porous structure. The obtained PCO was used to remove uranyl ions from an aqueous solution, demonstrating the maximum adsorption capacity of 450 mg·g−1. The adsorption capacity of PCO decreased by less than 7.51% after five adsorption-desorption cycles. PCO exhibited good adsorption selectivity (Kd = 3.45 × 104 mL·g−1) for uranyl ions. The adsorption mechanism of PCO was also discussed. The material showed good potential for application in the treatment of wastewater containing uranyl ions.
Production cost, capacitance, and electrode materials safety are the key factors to be concerned about for supercapacitors. In this work, a type of carbon nanosheets was produced through the carbonization of tripotassium citrate monohydrate and nitric acidification. Subsequently, a well-designed manganese dioxide/carbon nanosheets composite was synthesized through hydrothermal treating. The carbon nanosheets served as the substrate for growing the manganese dioxide, regulating its distribution, and preventing it from inhomogeneous dimensions and severe agglomeration. Many manganese dioxide nanosheets grew vertically on the numerous functional groups generated on the surface of the carbon nanosheets during acidification. The synergistic combination of carbon nanosheets and manganese dioxide tailors the electrochemical performance of the composite, which benefits from the excellent conductivity and stability of carbon nanosheets. The carbon nanosheets derived from tripotassium citrate monohydrate are conducive to the remarkable performance of manganese dioxide/carbon nanosheets electrode. Finally, an asymmetric supercapacitor with active carbon as the cathode and manganese dioxide/carbon nanosheets as the anode was assembled, achieving an outstanding energy density of 54.68 Wh·kg–1 and remarkable power density of 6399.2 W·kg–1 superior to conventional lead-acid batteries. After 10000 charge-discharge cycles, the device retained 75.3% of the initial capacitance, showing good cycle stability. Two assembled asymmetric supercapacitors in series charged for 3 min could power a yellow light emitting diode with an operating voltage of 2 V for 2 min. This study may provide valuable insights for applying carbon materials and manganese dioxide in the energy storage field.
Copper(I) selenide-nanocrystalline semiconductor was synthesized via one-step mechanochemical synthesis after 5 min milling in a planetary ball mill. The kinetics of synthesis was followed by X-ray powder diffraction analysis and specific surface area measurements of milled 2Cu/Se mixtures. The X-ray diffraction confirmed the orthorhombic crystal structure of Cu2Se with the crystallite size ~25 nm. The surface chemical structure was studied by X-ray photoelectron spectroscopy, whereby the binding energy of the Cu 2p and Se 3d signals corresponded to Cu+ and Se2– oxidation states. Transmission electron microscopy revealed agglomerated nanocrystals and confirmed their orthorhombic structure, as well. The optical properties were studied utilizing ultraviolet-visible spectroscopy and photoluminescence spectroscopy. The direct bandgap energy 3.7 eV indicated a blue-shift phenomenon due to the quantum size effect. This type of Cu2Se synthesis can be easily adapted to production dimensions using an industrial vibratory mill. The advantages of mechanochemical synthesis represent the potential for inexpensive, environmentally-friendly, and waste-free manufacturing of Cu2Se.
