Compared with the traditional Haber Bosch process, green and pollution-free electrocatalytic nitrogen reduction (NRR) has received considerable attention in the electrocatalysis field in the last decade. To address the issue of its low reactivity as well as the existence of competitive reactions, efficient electrocatalysts are particularly important. In this paper, NiO nanomaterials were synthesized by a simple water bath reaction. The effect of different calcination temperatures on the structure of NiO catalyst and its catalytic activity was studied. Uniform NiO-600 nanoparticles (56 ± 9.3 nm) obtained at 600 ℃ showed the best electrocatalytic NRR activity with an NH3 yield of 12 μg h− 1 mg− 1 and a Faraday efficiency of 5.5% at -0.5V (vs.RHE). The small particle size of the nanoparticles provided more active sites and the oxygen-rich vacancies facilitated the adsorption and activation of N2, which improved the catalytic activity of NiO-600. This study highlights the need for calcination temperature regulation and the huge impact on catalyst structure.

Hierarchically porous carbon foam composites with highly dispersed Fe2O3 nanoparticles confined in the foam pores, facilely fabricated by hydrolysis-driven emulsion polymerization strategy. The as-generated acidic conditions of Fe3+ hydrolysis could catalyze the polymerization of phenolic resin, and the carbon-based composite materials containing iron oxides were obtained in situ. The structural characterization results show that HCF@Fe2O3 NPs-2 electrode has the largest specific surface area (549 m2/ g) and pore volume (0.46 cm3/ g). Electrochemical results indicates that typical HCF@Fe2O3 NPs-2 electrode displays good capacitive properties. including high specific capacitance (225 F/g at 0.2 A/g current density). Excellent magnification performance (capacity retention rate 80% as current density increases from 0.2 to 10 A/g). At the same time, HCF@SnO2 NPs was successfully synthesized by replacing hydrolyzed tin tetrachloride with ferric chloride. This study provides a new idea for the preparation of metal oxide–carbon matrix composites, and also highlights the potential of such carbon foams in application of energy storage.

High-temperature friction performances of graphite blocks (GBs) and zinc phosphate impregnated graphite blocks (IGBs) were evaluated under various friction temperatures. The surface of IGB exhibited extremely lower average friction coefficient values, that was 0.007 at 400 °C and 0.008 at 450 °C, in comparison to that of GB (0.13 at 400 °C and 0.16 at 450 °C, respectively). The worn surface of IGB in the high-temperature friction test was smoother and more complete than that of GB. The wear under high temperature and load caused the transformation of zinc pyrophosphate to zinc metaphosphate and the formation of a continuous large-area boundary lubrication layer combined with graphite and metallic element on the wear surface. The superior tribology property of IGB could be attributed to the digestion of iron oxides by tribo-chemical reactions and passivation of the exposed dangling covalent bonds. Specifically, the layered structure generated on the IGB wear interface effectively decreased the adhesive forces and prevented the surface from serious damage.