Hydrogen induced interface engineering in Fe2O3–TiO2 heterostructures for efficient charge separation for solar-driven water oxidation in photoelectrochemical cells

Approximate energy band diagram and charge transfer mechanism for the Fe2O3–TiO2 photoanode (left) and Fe2O3–H:TiO2 photoanode (right) with external applied anodic potential under illumination.

The Effect of Hydrogen on the Nanoindentation Behavior of Heat Treated 718 Alloy

In this study, the effect of precipitates on the surface mechanical properties in the presence of hydrogen (H) is investigated by in situ electrochemical nanoindentation. The nickel superalloy 718 is subjected to three different heat treatments, leading to different sizes of the precipitates: (i) solution annealing (SA) to eliminate all precipitates, (ii) the as-received (AR) sample with fine, dispersed precipitates, and (iii) the over-aged (OA) specimen with coarser precipitates. The nanoindentation is performed using a conical tip, and a new method of reverse imaging is employed to calculate the nano-hardness. The results show that the hardness of the SA sample is significantly affected by H diffusion. However, it could be recovered by removing the H from its matrix by applying an anodic potential. Since the precipitates in the OA and AR samples are different, they are influenced by H differently. The hardness increase for the OA sample is more significant in −1200mV, while for the AR specimen, the H is more effective in −1500mV. In addition, the pop-in load is reduced when the samples are exposed to cathodic charging, and it cannot be fully recovered by switching to an anodic potential.

A Novel Electrochemical Process for Desulfurization in the CaO-SiO2-Al2O3 System

The effect of electric potential on the sulfide capacity of the CaO-SiO2-Al2O3 system was evaluated by applying voltages in the range of −1.5 to 1.5 V at 1823 K in a C/CO gas equilibrium. When the cathodic potential (−1.5 to 0 V) was applied, it was confirmed that the sulfur partition ratio increased based on the electrochemical reaction of sulfur (S + 2e− = S2−). However, the reversibility of the electrochemical resulfurization reaction (S2− = S + 2e−) in slag was not established in the reverse (anodic) potential region (0–1.5 V), yet the sulfur partition ratio increased. In particular, sulfur evaporation was observed in the anodic potential region. Therefore, in the present study, potential anodic electro-desulfurization mechanisms based on sulfur evaporation are proposed. To verify these mechanisms, sulfur evaporation is discussed in detail as a function of the thermodynamic stability of sulfur in the slag.

Interphase-oxidized ruthenium metal with half-filled d-orbitals for hydrogen oxidation in an alkaline solution

The interphase-oxidized Ru clusters with half-filled 4d-orbitals can maintain a metallic surface for binding hydrogen at high anodic potential, leading to a high reactivity for hydrogen oxidation reaction in alkaline.