Constructing core@shell structured photothermal nanosphere with thin carbon layer confined Co-Mn bimetals for pollutant degradation and solar interfacial water evaporation

Photothermal material applied in environmental governance has attracted growing attention.By combining the Stober method and dopamine-triggered coating strategy,Co-Mn precursor was in situ incorporated into the poly dopamine(PDA)layer over the surface of silica cores.Afterwards,a unique photothermal nanosphere with SiO_(2)core and thin carbon layer and dual Co-Mn oxides shell was allowed to form by sequential heat treatment in the inert atmosphere(SiO_(2)@CoMn/C).The bimetallic fraction of Co/Mn in the carbon layer and post-treatment calcination temperature was comprehensively tuned to optimize the peroxymonosulfate(PMS)activation performance of the catalyst.The state of bimetallic species was studied including their physical distribution,chemical valence,and interplay by various characterizations.Impressively,Co oxides appear as dominant monodispersed nanoparticles(~10 nm),while Mn with cluster-like morphology is observed to uniformly distribute over thin-layer carbon and adhered to the surface of SiO_(2)nanospheres(~250 nm).The calcined temperature could tune the oxidized state of Co species,leading to the optimization of the catalytic performance of introduced dual metal species.As a result,this obtained optimal catalyst integrated the advantages of exposed bimetallic CoMn species and N-doped thin carbon to deliver excellent catalytic PMS activation performance and photothermal synergetic catalytic mineralization ability for diversiform pollutants.Further reactions condition controls and anion interference studies were conducted to identify the adaptability of the optimal catalyst.Moreover,the application of solar-driven interfacial water evaporation using optimal SiO_(2)@Co_3Mn_1/C-600 catalyst was explored,showing a high water evaporation rate of 1.48 kg·m^(-2)·h^(-1)and an efficiency of 95.2%,further revealing a comprehensive governance functionality of obtained material in the complex pollution condition.

Coupling N-doping and confined Co_(3)O_(4) on carbon nanotubes by polydopamine coating strategy for pleiotropic water purification

The development of effective and sustainable solutions for pleiotropic water purification becomes urgent and attractive.Heterogeneous Fenton-like catalysts for activation of peroxymonosulfate(PMS)to purify organic wastewater show great promise.In this work,by tuning metal loading with an in-situ polydopamine coating strategy,oxygen vacancy-enriched Co_(3)O_(4) loading on N-doped carbon nanotubes(CNTs)were constructed to enhance PMS activation efficiency for pollutants degradation.Impressively,the obtained modified CNTs afford a well-developed N-containing network structure,which is further endowed with abundant Co(Ⅱ)/Co(Ⅲ)redox cycles and significant metal-carbon interactions.In particular,the surface N doping in CNTs might induce the oriented enrichment of pollutants around the catalyst,which reduces the migration distance and correspondingly improves the utilization of reactive oxidative species.The electron transfer efficiency of the catalyst can be further improved by incorporating oxygen vacancy-enriched Co_(3)O_(4).The performance results show that the optimal NC/Co-1 could mineralize 20×10^(-6)of bisphenol A(BPA)by almost 98%in 8 min.A low reaction activation energy(26.05 kJ·mol^(-1))in BPA degradation was demonstrated by the NC/Co-1.More importantly,NC/Co-1 can inherit excellent degradation performance towards oxytetracycline,2,4-dichlorophenol,and tetracycline,showing wide practical flexibility.In addition,by virtue of the photothermal conversion property,NC/Co-1 achieves an additive function for interfacial solar water evaporation(1.84 kg·m^(-2)·h^(-1),112.51%),showing impressive potential for clean water recovery under complicated environmental pollution conditions.

Effects of process parameters on fragment and refinement of millimeter- grade coarse grains for 316LN steel during hot cogging

The heterogeneous mixed-grain microstructure is a common defect for the heavy forging of 316LN austenitie stainless steel. Isothermal compression experiments were performed on a Gleeble-3500 thermo-mechanical simulator to investigate the effect of process parameters on the fragment and re- finement of millimeter-grade coarse grains （MCGs） during hot cogging. The experimental results in- dicate that the stress of MCG specimens is much larger than that of fine grain （FG） ones at 1150 ℃, while the stress difference between MCG and FG samples became smaller at 1200 ℃. Moreover, the MCGs can be well fragmented and refined under the condition of temperature of 1200 ℃, strain rate of 0.01 s-1 , and reduction rate of 50%. Meanwhile, numerical simulations were conducted to study the influences of temperature, strain and strain rate on microstructure evolution. The results of ex- periments and simulations comprehensively demonstrate that the MCG results in the increase of de- formation resistance and incompatibility of deformation, and it can be fragmented and refined at 1200 ℃ so that the plastic deformation energy decreases remarkably with the increase of temperature from 1 150 to 1200 ℃.