Comparative study on CeO2 catalysts with different morphologies and exposed facets for catalytic ozonation: performance, key factor and mechanism insight.

Morphology and facet effects of metal oxides in heterogeneous catalytic ozonation (HCO) are attracting increasing interests. In this paper, the different HCO performances for degradation and mineralization of phenol of seven ceria (CeO2) catalysts, including four with different morphologies (nanorod, nanocube, nanooctahedron and nanopolyhedron) and three with the same nanorod morphology but different exposed facets, are comparatively studied. CeO2 nanorods with (110) and (100) facets exposed show the best performance, much better than that of single ozonation, while CeO2 nanocubes and nanooctahedra show performances close to single ozonation. The underlying reason for their different HCO performances is revealed using various experimental and density functional theory (DFT) calculation results and the possible catalytic reaction mechanism is proposed. The oxygen vacancy (OV) is found to be pivotal for the HCO performance of the different CeO2 catalysts regardless of their morphology or exposed facet. A linear correlation is discerned between the rate of catalytic decomposition of dissolved ozone (O3) and the density of Frenkel-type OV. DFT calculations and in-situ spectroscopic studies ascertain that the existence of OV can boost O3 activation on both the hydroxyl (OH) and Ce sites of CeO2. Conversely, various facets without OV exhibit similar O3 adsorption energies. The OH group plays an important role in activating O3 to produce hydroxyl radical (∙OH) for improved mineralization. This work may offer valuable insights for designing Facet- and OV-regulated catalysts in HCO for the abatement of refractory organic pollutants.

Carboxymethyl cellulose/polyvinyl alcohol composite aerogel supported beta molecular sieve for CH4 adsorption and storage.

Biomass aerogel is attractive in various applications due to their renewable, biodegradable and eco-friendly advantages. Herein, a novel beta molecular sieve/carboxymethyl cellulose/polyvinyl alcohol composite aerogel (beta/CP) is prepared by direct mixing and directional freeze-drying as an efficient gas adsorbent with hierarchical porosity. The beta molecular sieve is uniformly dispersed in the three-dimensional skeleton of the aerogel. By adjusting the loading mass of the beta molecular sieve to constitute a reasonable porosity and pore size distribution, the synergistic effect between pore structures of different scales improves the adsorption performance. The experiment results of beta/CP-4 show that the CH4 adsorption capacity can reach 60.33 cm3/g at 298 K and 100 bar, which is almost the same as that of the pure beta molecular sieve (62.09 cm3/g). The strong interaction between the aerogel and it prevents the molecular sieve agglomeration, improves the pore utilization, and also reduces the cost of using molecular sieve adsorbent. The above results indicate that the composite has good potential for application in the field of CH4 storage.

Efficacy of Epley's maneuver plus betahistine in the management of PC-BPPV: A systematic review and meta-analysis.

BACKGROUND: To evaluate the efficacy of Epley's maneuver plus betahistine in the management of patients with posterior canal benign paroxysmal positional vertigo (PC-BPPV). METHODS: Electronic databases including PubMed, Embase, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure, and Wanfang were searched from their inception to April, 2022. The effect size was analyzed by calculating the pooled risk ratio estimates of efficacy rate, recurrence rate, and standardized mean differences (SMD) of dizziness handicap inventory (DHI) score with a 95% confidence interval (CI). Sensitive analysis was performed simultaneously. RESULTS: A total of 9 randomized controlled trials with 860 PC-BPPV patients were included in the meta-analysis, in which 432 were treated with Epley's maneuver plus betahistine, and 428 received Epley's maneuver alone. The meta-analysis revealed that Epley's maneuver plus betahistine significantly improved DHI score than Epley's maneuver alone (SMD = -0.61, 95% CI -0.96 to -0.26, P = .001). In addition, both Epley's maneuver plus betahistine and Epley's maneuver groups had comparable outcomes in efficacy rate and recurrence rate. CONCLUSION: This meta-analysis shows that Epley's maneuver plus betahistine in PC-BPPV patients had favorable effects on DHI score.

Carbon Aerogels as Electrocatalysts for Sustainable Energy Applications: Recent Developments and Prospects.

Carbon aerogel (CA) based materials have multiple advantages, including high porosity, tunable molecular structures, and environmental compatibility. Increasing interest, which has focused on CAs as electrocatalysts for sustainable applications including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and CO2 reduction reaction (CO2RR) has recently been raised. However, a systematic review covering the most recent progress to boost CA-based electrocatalysts for ORR/OER/HER/CO2RR is now absent. To eliminate the gap, this critical review provides a timely and comprehensive summarization of the applications, synthesis methods, and principles. Furthermore, prospects for emerging synthesis, screening, and construction methods are outlined.

Konjac glucomannan/cellulose nanofibers composite aerogel supported HKUST-1 for CO2 adsorption.

Biomass aerogels are attractive in various applications owing to their inherent advantages of renewability, biodegradability and eco-friendly. Herein, a novel composite aerogel of konjac glucomannan (KGM)/TEMPO-oxidized cellulose nanofibers (TOCNF)@HKUST-1 (KTA@HKUST-1) is prepared through a facile vacuum impregnation method combined with the directional freeze-drying process, which using KGM and TOCNF as raw materials. The structural analyses disclose that the KTA@HKUST-1 has a hierarchical porosity, in which HKUST-1 can provide micropores for adsorption, while the meso-/macropores from KTA act as high-speed channels to improve diffusion and mass transfer rate to transport CO2 components into the micropores of HKUST-1. The experiment results of KTA@HKUST-1-10 (KTA@H10) show that the CO2 adsorption capacity can reach 3.50 mmol·g-1 at 1 bar and 298 K, and the adsorption capacity retention rate as high as 91.43% after 7 cycles. In addition, the CO2/N2 adsorption selectivity of KTA@H10 can reach 18.42, which has an excellent potential for selective CO2 adsorption.

Nitrogen-doped carbon composite derived from ZIF-8/polyaniline@cellulose-derived carbon aerogel for high-performance symmetric supercapacitors.

Cellulose derived carbon aerogel (CA) with unique three-dimensional network coated with polyaniline (PANI) on its surface is used as a scaffolding framework to anchor ZIF-8. The designed ZIF-8 derived porous carbon (ZC)/PANI@CA (ZPCA) hybrid carbon composite through a facile solution immersion chemical route and subsequent carbonization process is employed as electrode for supercapacitor, which has contributed a large specific surface area, a hierarchical porous structure and reasonable N content (up to 6.27 at.%). The synthesized ZPCA electrode achieves an outstanding capacitance of 388 F g-1 at 0.5 A g-1 as well as an excellent cycling performance. More inspiringly, the symmetric supercapacitor based ZPCA achieves a high energy density of 13.4 Wh kg-1 at a power density of 250 W kg-1 using 2 M KOH aqueous solution, and an ultrahigh energy density of 81.8 Wh kg-1 at a power density of 950 W kg-1 is realized using Et4NBF4/AN electrolyte.