Designing and producing a low-cost, high-current-density electrode with good electrocatalytic activity for the oxygen evolution reaction (OER) is still a major challenge for the industrial hydrogen energy economy. In this study, nanostructured Fe-doped CuCo(OH)2 was discovered to be a precedent electrocatalyst for OER with low overpotential, low Tafel slope, good durability, and high electrochemically active surface sites at reduced mass loadings. Fe-doped CuCo(OH)2 nanosheets are made using a hydrothermal synthesis process. These nanosheets are clumped together to form a highly open hierarchical structure. When used as an electrocatalyst, the Fe-doped CuCo(OH)2 nanosheets required an overpotential of 260 mV to reach a current density of 50 mA cm−2. Also, it showed a small Tafel slope of 72.9 mV dec−1, and superior stability while catalyzing the generation of O2 continuously for 20 hours. The Fe-doped CuCo(OH)2 was found to have a large number of active sites which provide hierarchical and stable transfer routes for both electrolyte ions and electrons, resulting in exceptional OER performance.

A high NIR-reflective black pigment is developed by Mn doping of Fe2O3. The pigment powders are prepared by spray pyrolysis, and the effect of the Mn concentration on the blackness and optical properties is investigated. Mn doping into the crystal lattice of -Fe2O3 is found to effectively change the powder color from red to black, lowering the NIR reflectance compared to that of pure Fe2O3. The pigment doped with 10% Mn, i.e., Fe1.8Mn0.2O3, exhibits a black color with an optical bandgap of 1.3 eV and a Chroma value of 1.14. The NIR reflectance of the prepared Fe1.8Mn0.2O3 black pigment is 2.2 times higher than that of commercially available carbon black, and this material is proven to effectively work as a cool pigment in a temperature rise experiment under near-infrared illumination.

Fe doped skutterudite CoSb3 with a nominal composition of FexCo1-xSb12 (0≤x≤2.5) have been synthesized by mechanical alloying (MA) of elemental powders, followed by vacuum hot pressing. Phase transformations during mechanical alloying and vacuum hot pressing were systematically investigated using XRD. Single phase skutterudite was successfully produced by vacuum hot pressing using as-milled powders without subsequent annealing. However, second phase of FeSb2 was found to exist in case of x≥2, suggesting the solubility limit of Fe with Co in this system. Thermoelectric properties as functions of temperature and Fe contents were evaluated for the hot pressed specimens. Fe doping up to x=1.5 with Co in FexCo4-xSb12 appeared to increase thermoelectric figure of merit (ZT) and the maximum ZT was found to be 0.78 at 525K in this study.