Dual-atom active sites embedded in two-dimensional C_(2)N for efficient CO_(2) electroreduction: A computational study

Double-atom catalysts(DACs)have emerged as an enhanced platform of single-atom catalyst for promoting electrocatalytic CO_(2) reduction reaction(CO_(2) RR).Herein,we present a density-functional theory study on CO_(2) RR performance of seven C_(2) N-supported homo-and heteronuclear DACs,denoted as M_(2)@C_(2) N.Our results demonstrate that there exists substantial synergistic effect of dual-metal-atom N_(2) M_(2) N_(2) active site and C_(2) N matrix on O=C=O bond activation.The dual-atom M_(2) sites are able to drive CO_(2) RR beyond C1 products with low limiting potential(UL).Specifically,C_(2) H4 formation is preferred on FeM@C_(2) N(M=Fe,Co,Ni,Cu)versus CH4 formation on CuM@C_(2) N(M=Co,Ni,Cu).Furthermore,^(*)CO+^(*)CO cobinding strength can serve as a descriptor for CO_(2) RR activity for making C_(2) products such that the moderate binding results in the lowest UL.Remarkably,C-affinity matters most to C-C bond coupling and C_(2) H4 formation while both C-and O-affinity control CH4 formation.Our results provide theoretical insight into rational design of DACs for efficient CO_(2) RR.

Antibacterial mechanism of lactobionic acid against Shewanella baltica and Shewanella putrefaciens and its application on refrigerated shrimp

Lactobionic acid(LBA)is a novel antibacterial agent that has attracted much interest in recent years.However,the study on the antibacterial effect of LBA on spoilage bacteria is rare.This study aims to investigate the antibacterial activity and mechanism of LBA on Shewanella baltica and Shewanella putrefaciens,which are the common spoilage microorganisms in chilled seafood.The results demonstrated that LBA was an effective bacteriostat against S.baltica and S.putrefaciens,with the minimum inhibitor concentration(MIC)of 8 mg/mL.Both the two Shewanella species could be completely killed by LBA at 2 MIC.LBA damaged the cell membrane integrity and increased outer membrane permeability,causing the increase in protein leakage and conductivity,which was supported by the bacterial morphology observed with scanning electron microscopy.Besides,LBA could interact with the bacterial genome DNA,resulting in the dysfunction of cell function.Moreover,LBA exhibited an effectively inhibitory effect on slowing down microbial growth,melanosis and lipid oxidation rate in refrigerated shrimp.These results suggest that LBA would be a promising antibacterial compound used in seafood.

Controlled synthesis of Pt-loaded yolk-shell TiO_(2)@SiO_(2) nanoreactors as effective photocatalysts for hydrogen generation

Yolk-shell and hollow structures are powerful platforms for controlled release,confined nanocatalysis,and optical and electronic applications.This contribution describes a fabrication strategy for a yolk-shell nanoreactor(NR)using a post decoration approach.The widely studied yolk-shell structure of silica-coated TiO_(2)(TiO_(2)@SiO_(2))was used as a model.At first,anatase TiO_(2) spheres were prepared,and subsequently were given a continuous coating of carbonaceous and silica layers.Finally,the carbonaceous layer was removed to produce a yolk-shell structure TiO_(2)@SiO_(2).By using an in-situ photodeposition method,Pt-encased spheres(Pt-TiO_(2)@SiO_(2))were synthesized with Pt nanoparticles grown on the surface of the TiO_(2) core,which contained void spaces suitable for use as NRs.The NR showed enhanced hydrogen production with a rate of 24.56 mmol·g^(-1)·h^(-1) in the presence of a sacrificial agent under simulated sunlight.This strategy holds the potential to be extended for the synthesis of other yolk-shell photocatalytic NRs with different metal oxides.