Hierarchical Metal-Polymer Hybrids for Enhanced CO2 Electroreduction.

The design of catalysts with high activity, selectivity, and stability is key to the electroreduction of CO2 . Herein, we report the synthesis of 3D hierarchical metal/polymer-carbon paper (M/polymer-CP) electrodes by in situ electrosynthesis. The 3D polymer layer on CP (polymer-CP) was first prepared by in situ electropolymerization, then a 3D metal layer was decorated on the polymer-CP to produce the M/polymer-CP electrode. Electrodes with different metals (e.g. Cu, Pd, Zn, Sn) and various polymers could be prepared by this method. The electrodes could efficiently reduce CO2 to desired products, such as C2 H4 , CO, and HCOOH, depending on the metal used. For example, C2 H4 could be formed with a Faradaic efficiency of 59.4 % and a current density of 30.2 mA cm-2 by using a very stable Cu/PANI-CP electrode in an H-type cell. Control experiments and theoretical calculations showed that the 3D hierarchical structure of the metals and in situ formation of the electrodes are critical for the excellent performance.

Highland Barley ß-Glucan Relieves Symptoms of Colitis via PPARα-Mediated Intestinal Stem Cell Proliferation.

Intestinal stem cells (ISCs) are necessary to maintain intestinal renewal. Here, we found that the highland barley ß-glucan (HBG) alleviated pathological symptoms and promoted the proliferation of intestinal stem cells in colitis mice. Notably, metabolomics studies showed that docosahexaenoic acid (DHA) was significantly increased by the HBG treatment. DHA is a ligand for peroxisome proliferator-activated receptor α (PPARα), which can promote ISC proliferation. Expectedly, HBG facilitated the expression of intestinal PPARα and the proliferation of ISCs in colitis mice. Further experiments verified that DHA significantly facilitated the expression of PPARα and the proliferation of ISCs in intestinal organoids. Intriguingly, the effect of DHA on ISC proliferation was reversed by the PPARα inhibitor. Together, our data indicate that HBG might accelerate PPARα-mediated ISC proliferation through DHA. This provides new insights into the effective application of polysaccharides in maintaining intestinal homeostasis.

Low temperature methanation of CO2 over an amorphous cobalt-based catalyst.

CO2 methanation is an important reaction in CO2 valorization. Because of the high kinetic barriers, the reaction usually needs to proceed at higher temperature (>300 °C). High-efficiency CO2 methanation at low temperature (<200 °C) is an interesting topic, and only several noble metal catalysts were reported to achieve this goal. Currently, design of cheap metal catalysts that can effectively accelerate this reaction at low temperature is still a challenge. In this work, we found that the amorphous Co-Zr0.1-B-O catalyst could catalyze the reaction at above 140 °C. The activity of the catalyst at 180 °C reached 10.7 mmolCO2 gcat -1 h-1, which is comparable to or even higher than that of some noble metal catalysts under similar conditions. The Zr promoter in this work had the highest promoting factor to date among the catalysts for CO2 methanation. As far as we know, this is the first report of an amorphous transition metal catalyst that could effectively accelerate CO2 methanation. The outstanding performance of the catalyst could be ascribed to two aspects. The amorphous nature of the catalyst offered abundant surface defects and intrinsic active sites. On the other hand, the Zr promoter could enlarge the surface area of the catalyst, enrich the Co atoms on the catalyst surface, and tune the valence state of the atoms at the catalyst surface. The reaction mechanism was proposed based on the control experiments.