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This study investigates the effects of carbonation curing and ye'elimite on the physical and chemical properties of ternesite to improve its hardening rate. The results showed that ternesite had a high carbonation activity and the additional benefit of CO 2 sequestration. The carbonation products included amorphous calcium carbonate, calcite, aragonite, gypsum, and either C-S-H gel or silica gel. The large amount of carbonated products improved the structure, densified the matrix, and was primarily responsible for the strong relationship between the mechanical strength and pore structure of the ternesite and its carbonation level. The strong carbonation activity of ternesite was caused by the rapid dissolution of calcium ions in the presence of CO 2. Ye'elimite was added, and the aluminium hydroxide produced by the carbonation reaction of ye'elimite appeared in the slurry, accelerating the hydration rate of ternesite and causing the carbonation and hydration reactions of ternesite to occur simultaneously. This significantly increased the carbonation rate and mechanical strength of ternesite at the early stage. The hardening rate of ternesite significantly increased under the simultaneous action of ye'elimite and carbonation curing. [ABSTRACT FROM AUTHOR]

The structural stability of supported metal nanoparticles determines the activity and longevity of heterogeneous catalysts. Unfortunately, the chemical/thermal working environment inevitably accelerates metal sintering to larger crystallites that leads to the degradation of catalytic performance. Here, we demonstrate that the distribution of defects in carbon support as an inherent parameter plays a crucial role in catalyst sintering. Based on in-situ transmission electron microscopy studies, the strong metal-support interaction between platinum (Pt) nanoparticles and defect-rich graphene nanoflakes largely suppresses metal sintering up to 700 °C. Particularly, the optimal carbon support can be achieved in the annealing process, in which the mass transfer and charge transport can be enhanced by accurately manipulating the distribution of defects in carbon matrix and graphitization degree. It is worth noting that the screened Pt/GNs-300 exhibits impressive oxygen reduction reaction performance with high half-wave potential (0.91 V), mass activity (108.1 A g–1 Pt) and excellent stability. By its ascendancy in ORR, the Pt/GNs-300 exhibits a high open-circuit voltage of 1.41 V and a maximum power density of 198.6 mW cm−2 in Zn-air battery, implying its brilliant practicability. This work paves a pathway for achieving sinter-resistant metal-loaded catalysts in energy electrocatalysis. The distribution of defects in carbon support plays a pivotal role in preventing metal sintering and maintaining the interfacial structure of the metal. In this work, we report that the strong metal-support interaction between Pt nanoparticles and defect-rich graphene nanoflakes largely suppresses metal sintering up to 700 °C. Particularly, the optimized Pt/GNs-300 catalyst exhibits remarkable ORR activity, and thus fascinating performance towards Zn-air battery. [Display omitted] • The Pt nanoparticles were semi-encapsulated in defect-rich carbon shells. • The migration and coalescence of Pt nanoparticles was suppressed completely below 700 °C. • Clarified the effect of defects modulation in carbon matrix on ORR performance. • The Pt/GNs-300 endows it a great application potential in Zn-air battery. [ABSTRACT FROM AUTHOR]

• The influences of various factors on the performance of magnesium oxychloride cement foam concrete were investigated. • Ethylene-vinyl acetate copolymer redispersible latex powder could inhibit the formation of Mg(OH) 2. • Ethylene-vinyl acetate copolymer redispersible latex powder could significantly stabilise 5Mg(OH) 2 ·MgCl 2 ·8H 2 O in water. The effects of the MgO to MgCl 2 molar ratio, fly ash content, hydrogen peroxide content, ethylene–vinyl acetate copolymer redispersible latex powder (EVA) content, and polypropylene fibre content on the performance of magnesium oxychloride cement foam concrete (MOCFC) were investigated by designing orthogonal experiments. The degrees of influence of each factor on the compressive strength, thermal conductivity, and water resistance of MOCFC were studied. A model was established that showed the relationship between the main influencing factors and the MOCFC performance. Microscopic and pore structure test results were used to analyse the EVA-modified chlorine oxide. The results showed that the hydrogen peroxide content and MgO to MgCl 2 molar ratio were the main factors affecting the performance of MOCFC. The regression effect between the model of the composite important factors affecting the MOCFC performance and the hydrogen peroxide content and MgO to MgCl 2 molar ratio was remarkable. EVA prevented the formation of magnesium hydroxide and slowed down the hydration rate of magnesium oxychloride cement (MOC) by forming magnesium acetate chelate. After immersion in water, the complex could prevent the decomposition of 5 Mg(OH) 2 ·MgCl 2 ·8H 2 O (phase 5). When the EVA content was greater than 9%, the EVA film gradually became continuous and complete, and combined with the MOC hydrate to form a grid structure, which was beneficial to improve the pore structure. [ABSTRACT FROM AUTHOR]