ABSTRACT
Hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are the two branches of artificial overall water splitting (OWS), in which the reaction efficiency usually depends on different specific catalysts. Although effective bifunctional electrocatalyst for OWS (HER and OER) are highly desired, designing and constructing such suitable materials is full of challenges to overcome several difficulties, involving slow kinetics, differences in catalytic mechanisms, large overpotential values, and low round-trip efficiencies. In this work, we reported a new bifunctional electrocatalyst Ru/RuO2-MoO2 catalyst (RRMC) via a redox solid phase reaction (RSPR) strategy to achieve the high electrocatalytic activity of OWS. Briefly, due to the restricted transport behavior of atoms in solid state precursor, the designed redox reaction occurred between the adjacent part of RuO2 and MoS2, forming Ru/RuO2 hybrid NPs and MoO2 plane. Therefore, the newly formed Ru/RuO2 hybrid NPs and MoO2 plane were tightly combined and used as an electrocatalyst for OWS. Benefiting from the exposed active sites and optimized electronic structure, the RRMC sample annealed at 500⯰C (RRMC-500) exhibited low overpotential for HER (18â¯mV) and for OER (260â¯mV) at 10â¯mAâ¯cm-2 under alkaline conditions. Especially, a low cell voltage of 1.54â¯V was required at 10â¯mAâ¯cm-2 under alkaline condition.
ABSTRACT
The purpose of this paper is to further investigate engineering ethics and its gap within accident analysis models. In this paper, at first, the role of human factors in the occurrence of accidents is presented. Then engineering ethics as an element of human factors is proposed. It is suggested that engineering ethics can provide engineers with the necessary guidelines to avoid possible accidents arising from their decisions and actions. In addition, the Challenger and Columbia space shuttle case studies that demonstrate the role of engineering ethics in the prevention and occurrence of accidents are discussed. Then sequential, epidemiological, and systemic accident analysis models are briefly investigated and negligence of engineering ethics as a gap in the accident analysis models is described. At the end, we suggest that by implementing engineering ethics as a controller within the system boundary in systemic accident models we may be able to identify and prevent the ethical causes of accidents.
Subject(s)
Accident Prevention , Engineering/ethics , Decision Making , Ethics, Professional , HumansABSTRACT
The (Zn(0.95)Mn(0.05)S)(2)·L (L = hexylamine and octylamine) hybrids show the optimal Mn(2+) luminescence and their thin films were fabricated on the quartz substrate layer by layer by a spin coating method, which revealed the linear relationship of the UV optical absorption and the Mn(2+) luminescence intensity with the layer numbers.
ABSTRACT
This paper describes a new way to control temperatures of heterogeneous exothermic reactions such as heterogeneous catalytic reaction and polymerization by using encapsulated nanoparticles of phase change materials as thermally functional additives. Silica-encapsulated indium nanoparticles and silica encapsulated paraffin nanoparticles are used to absorb heat released in catalytic reaction and to mitigate gel effect of polymerization, respectively. The local hot spots that are induced by non-homogenous catalyst packing, reactant concentration fluctuation, and abrupt change of polymerization rate lead to solid to liquid phase change of nanoparticle cores so as to avoid thermal runaway by converting energies from exothermic reactions to latent heat of fusion. By quenching local hot spots at initial stage, reaction rates do not rise significantly because the thermal energy produced in reaction is isothermally removed. Nanoparticles of phase change materials will open a new dimension for thermal management of exothermic reactions to quench local hot spots, prevent thermal runaway of reaction, and change product distribution.
