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Tea saponin (TS) is extracted from the seeds of the tea plant and is generally regarded as a safe compound that has insecticidal properties and can act synergistically with other compounds. In this study, the activities of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and the levels of malondialdehyde (MDA) were compared in midgut tissues of third instar larvae of the diamondback moth (DBM), Plutella xylostellaL. (Lepidoptera: Plutellidae). The larvae were fed on three different host plants, cabbage (Brassica oleraceaL. var. capitata[Capparales: Brassicaceae]), radish (Raphanus sativusL. var. radiculusPersi [Capparales: Brassicaceae]), or rape (Brassica campestrisL. [Capparales: Brassicaceae]), that had been treated with TS. Higher SOD, POD, and CAT activities were found in DBM larvae fed on cabbage after LC20(concentration that induced 20% larval mortality) or LC50(concentration that induced 50% larval mortality) treatment than on the control. On rape, TS treatments led to lower SOD and CAT activities than in the control and to higher POD activities after 24 h. MDA content increased in larvae fed on rape but decreased in larvae fed on radish after 12 h. Our results indicated that DBM larvae are more susceptible to TS on rape than on cabbage and radish, suggesting that this treatment may be an economic and effective means of controlling DBM on rape.

To explore an efficient catalytic system with high activity and selectivity is the key to improve Fischer–Tropsch synthesis (FTS) technology and the main focus in the academic field. Herein, a photothermocatalytic system for FTS was constructed by combining thermo-active components with photosensitive supports. 20 wt% and 30 wt% Co supported on TiO2nanotube (TNT) catalysts were prepared through an incipient wetness impregnation method (named 20% Co/TNT and 30% Co/TNT) and were applied to a photothermocatalytic process to investigate the role of ultraviolet (UV) illumination in the traditional thermochemical FTS reaction. The results indicated that the introduction of UV light dramatically improved CO conversion, from 9.2% to 64.0% for 20% Co/TNT and from 8.6% to 17.1% for 30% Co/TNT. In addition, UV illumination gave rise to an increase in light paraffin selectivity. The improvement of CO conversion was found to be related to the photogenerated electron transfer from TNTs to active Co sites upon UV light irradiation, which caused the Co sites to have increased surface electron density and subsequently enhanced the adsorption and activation of CO molecules at Co sites. Meanwhile, the increase in light paraffin selectivity was attributed to the photo-promoted hydrogenation of olefin and the hydrogenolysis of the long-chain hydrocarbons. The present work promoted a deeper understanding of the photothermal FTS reaction mechanism and demonstrated that photothermocatalysis could have potential for enhancing FTS catalytic performance and adjusting product distribution.

From the viewpoint of controlling the visible-light-driven activities of catalysts containing metal nanoparticles (NPs) by tuning the microstructures of semiconducting supports, we employed a postsynthetic thermal modification approach to prepare carbon nitride (C3N4) species featuring different microstructures and then we synthesized Co and Ni NPs supported by these C3N4species, which were used to catalyze the room-temperature H2evolution from ammonia borane (NH3BH3). The systematic investigation showed that the catalysts had different activities under light irradiation. Compared with the pristine C3N4-based catalyst, all the modified C3N4-based catalysts had enhanced activities. The highest active Co catalyst with a total turnover frequency of 93.8 min–1was successfully obtained, which exceeded the values of all the reported heterogeneous noble metal-free catalysts. The structure characterizations indicated that the postmodified porous C3N4species had the different band structures, photoluminescence lifetime, and photocurrent density under visible light irradiation, leading to the different separation efficiency of photogenerated charge carriers. These characteristics helped us regulate the electronic characteristics of Co and Ni NPs in the supported catalysts and then led to the significantly different and enhanced activity in the visible-light-driven H2evolution.

CO2(dry) reforming of methane (DRM) has received much attention as an important process for the transformation and applications of two greenhouse gases (CH4and CO2). In the present study, non-precious monometallic molybdenum nitride Mo2N and bimetallic molybdenum nitrides Ni3Mo3N and Co3Mo3N were synthesized and used as catalysts for DRM. It was found that the Mo2N, Ni3Mo3N and Co3Mo3N materials were catalytically active in the DRM reaction above 550 °C. Compared to the monometallic nitride Mo2N, the bimetallic nitrides Co3Mo3N and Ni3Mo3N showed enhanced catalytic activity, stability and resistance to oxidation. Particularly, Co3Mo3N exhibited the highest activity and stability among the three samples, which could be due to three factors, namely, the synergistic effect between the Mo and interstitial metal Co in the interstitial structure, the roughly equal adsorption capacities and consumption rates of reactants CO2and CH4and their increment on the surface of the catalyst at high reaction temperatures, as well as a possible conversion balance on the active centers established. The results suggest that the low-cost Co3Mo3N is a promising candidate for DRM.

Organic electrosynthesis as an emerging green and advantageous alternative to traditional synthetic methods has achieved remarkable progress in recent years because sustainable electricity can be employed as traceless redox agents. To surmount the over-oxidation/reduction issues of direct electrolysis, mediated or indirect electrochemical processes are attaining remarkable significance and promoting the selectivity of products. Molecular electrocatalysts, benefiting from the easily electronic and steric modulation, suffers from readily degradation issue in most cases. Remarkably, heterogeneous catalysts have drawn more attention due to their high activity, stability, and recyclability. Hence, in this review, the most recent growth of heterogeneous catalysts modified electrodes for organic electrosynthesis were summarized, highlighting structural optimization and electrochemical performance of these materials as well as reaction mechanism. Furthermore, key challenges and future directions in this area were also discussed.