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The SEM, XRD, laser particle size analyzer, Zeta, and TOC organic carbon absorber were used, the particle morphology, particle gradation and mineral composition of tunnel slag powder under construction were tested, and its Zeta potential and superplasticizer adsorption performance were researched. The results show that the slag powder particles are irregularly shaped, angular, and the particle size is different. Under the same sand making process, the specific surface area of basalt powder is the largest, and the quartz rock powder is the smallest. The absolute value of Zeta potential of quartz rock powder is the largest, and the basalt powder is the smallest. The adsorption rate of granite powder to superplasticizer is the largest, and the quartz rock powder is the smallest. The long side chain adsorption group superplasticizer has the largest adsorption rate in the tunnel slag powder, and the phosphate adsorption superplasticizer has the smallest adsorption rate. [ABSTRACT FROM AUTHOR]

Calcium sulphoaluminate (CSA) cement is an environmentally friendly material and has its specific characteristics, including good resistance to ingress of external chlorides. To date, performance evolution and relevant mechanism of CSA cement-based materials during its service in chloride environment are still not clear, and needs a thorough study before its widely application in practice. This paper reviews the research progress on the chloride transport, chloride binding and corrosion behavior of steel in CSA cement under chloride environment. The crucial factors influencing the resistance of CSA cement-based materials to chloride attack are emphasized, such as water-to-binder ratio, molar ratio of gypsum to ye'elimite and use of supplementary cementitious materials. Meanwhile, future research directions on chloride related durability issues of CSA are recommended. [ABSTRACT FROM AUTHOR]

Nanomaterials are widely used in cement to improve the various properties of cement-based materials. Nano-CSH is considered as an effective accelerator for the hydration of cement. This paper studied the effects of nano-CSH on the hydration behavior and compressive strength of cementitious materials with various mineral admixtures. Isothermal calorimetry test was used to study the early hydration of cement paste. Thermogravimetric and X-ray diffraction tests were used to study the evolution of hydration product and unhydrated mineral phases in the hydrated cement paste. The presentation of compressive strength can evaluate the influence of nano-CSH on the property of cement-based material at the macro level. The obtained results show that the used nano-CSH can promote the hydration of tricalcium silicate (C3S), and is more active on the hydration of tricalcium aluminate (C3A) in the samples with GGBFS. The presence of nano-CSH can definitely accelerate the secondary hydration reaction of mineral admixtures. [ABSTRACT FROM AUTHOR]

We previously reported that the hydrolysis of Ir3+ in homogeneous solution could be triggered by irradiation with light whose energy was larger than a threshold value. In this work, we demonstrated that, by introducing Fe2O3 particles into solution, the incident light energy-restriction for the photo-catalyzed hydrolysis could be broken and the hydrolysis occurred at the Fe2O3/solution interface. The photo-generated holes on the Fe2O3 surface played a key role in oxidizing Ir(iii) to Ir(iv) species and triggered the deposition of IrOx. We showed that this photo-catalyzed surface hydrolysis is a universal phenomenon that takes place on the surface of many n-type semiconductors such as Fe2O3, TiO2, and Ag3PO4. As IrOx is an efficient catalyst for oxygen evolution reaction, surface hydrolysis is a general, facile and efficient strategy to prepare semiconductor/IrOx composites, which can be used as anodic materials for photoelectrochemical water splitting. [ABSTRACT FROM AUTHOR]

Ag/Ag3PO4 composite nanoplate photoanodes were fabricated by electrogeneration of Ag3PO4 on the surface of vertically aligned Ag nanoplates (NPs) in phosphate solution. The outside Ag3PO4 layer acted as a light-absorbing material to generate electron–hole pairs, while the inside Ag NPs acted as both the framework and the electrical connector between Ag3PO4 and the conducting substrate. The obtained composite photoanodes showed a high catalytic activity toward photoelectrochemical (PEC) oxygen evolution reaction (OER). The photoinduced holes reacted with water to generate oxygen on the Ag3PO4 surface, while the photoinduced electrons were efficiently transported to the counter electrode by highly conductive Ag NPs. The Ag/Ag3PO4 composite photoanode exhibited a photocurrent density of 0.25 mA cm−2 at 0.500 V vs. SCE, which is the highest among reported values obtained under conditions similar to this work. The amount of evolved oxygen was monitored to evaluate the percentage of the photocurrent involved in PEC OER, and the Faraday efficiency for PEC OER was obtained to be ca. 95.6%, indicating that most of the photoinduced holes were engaged in OER. The in situ PEC oxidation of Ag to Ag3PO4, which compensated the loss of Ag3PO4 during PEC OER, makes the Ag/Ag3PO4 composite a self-healing system for OER in phosphate solution. [ABSTRACT FROM AUTHOR]

Highlights: [•] Monoclinic WO3 nanoneedles (NNs) were modified with α-Fe2O3 nanocrystals. [•] Deposition of α-Fe2O3 on WO3 NNs extends the absorption band to the visible region. [•] The WO3 NNs/α-Fe2O3 photoanode exhibits high activity for solar water oxidation. [•] Cobalt-phosphate (Co-Pi) was used as O2 evolving catalyst to modify the photoanode. [•] Co-Pi layer greatly improve the stability of photoanode for O2 evolution reaction. [ABSTRACT FROM AUTHOR]

Highlights: [•] WO3 nanoneedles were grown on FTO substrates for solar water oxidation. [•] Nickel-borate (Ni-Bi) was used as oxygen-evolving catalyst to modify WO3 nanoneedles. [•] Deposition of Ni-Bi on WO3 nanoneedles improves the activity toward O2 evolution reaction. [•] WO3 nanoneedles/Ni-Bi composites show superior photostability to WO3 nanoneedles. [Copyright &y& Elsevier]

We previously reported that the hydrolysis of Ir 3+ in homogeneous solution could be triggered by irradiation with light whose energy was larger than a threshold value. In this work, we demonstrated that, by introducing Fe 2 O 3 particles into solution, the incident light energy-restriction for the photo-catalyzed hydrolysis could be broken and the hydrolysis occurred at the Fe 2 O 3 /solution interface. The photo-generated holes on the Fe 2 O 3 surface played a key role in oxidizing Ir(iii) to Ir(iv) species and triggered the deposition of IrO x . We showed that this photo-catalyzed surface hydrolysis is a universal phenomenon that takes place on the surface of many n-type semiconductors such as Fe 2 O 3 , TiO 2 , and Ag 3 PO 4 . As IrO x is an efficient catalyst for oxygen evolution reaction, surface hydrolysis is a general, facile and efficient strategy to prepare semiconductor/IrO x composites, which can be used as anodic materials for photoelectrochemical water splitting.