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Stainless steel made to rust: a robust water-splitting catalyst with benchmark characteristics
(2015)
The oxygen evolution reaction (OER) is known as the efficiency-limiting step for the electrochemical cleavage of water mainly due to the large overpotentials commonly used materials on the anode side cause. Since Ni–Fe oxides reduce overpotentials occurring in the OER dramatically they are regarded as anode materials of choice for the electrocatalytically driven water-splitting reaction. We herewith show that a straightforward surface modification carried out with AISI 304, a general purpose austenitic stainless steel, very likely, based upon a dissolution mechanism, to result in the formation of an ultra-thin layer consisting of Ni, Fe oxide with a purity >99%. The Ni enriched thin layer firmly attached to the steel substrate is responsible for the unusual highly efficient anodic conversion of water into oxygen as demonstrated by the low overpotential of 212 mV at 12 mA cm−2 current density in 1 M KOH, 269.2 mV at 10 mA cm−2 current density in 0.1 M KOH respectively. The Ni, Fe-oxide layer formed on the steel creates a stable outer sphere, and the surface oxidized steel samples proved to be inert against longer operating times (>150 ks) in alkaline medium. In addition Faradaic efficiency measurements performed through chronopotentiometry revealed a charge to oxygen conversion close to 100%, thus underpinning the conclusion that no “inner oxidation” based on further oxidation of the metal matrix below the oxide layer occurs. These key figures achieved with an almost unrivalled-inexpensive and unrivalled-accessible material, are among the best ever presented activity characteristics for the anodic water-splitting reaction at pH 13.
Mit einem systematischen Ansatz konnte basierend auf gering aufgelösten Daten (Bodenkarte, Höhenmodell, Landnutzungsklassifikation) das theoretische Expansionspotential für Ackerflächen in der Provinz Tjumen (Westsibirien, Russische Föderation) abgeschätzt werden. Die theoretisch mögliche Ausdehnung der Ackernutzung um 57% in den landwirtschaftlich relevanten Gebieten konnte allerdings nur zur Hälfte mit Groundtruthdaten in 3 Testareas (je 400 km²) validiert werden. Darüber hinaus waren 52% dieser positiven Validierungspunkte auf Ackerbrachen verortet, die derzeit nicht ökonomisch rentabel zu bewirtschaften sind. Insgesamt kann daher nur eine Expansion der Ackerflächen um 14,5% (? 1900 km² bzw. 1,1% der Gesamtfläche) als potentiell möglich angesehen werden.
The global climate system is currently warming due to the increase in CO2 emissions caused by humans. Technically oriented efficiency strategies are seen more frequently as solutions to reach the European Union’s maximum two degrees Celsius target. Companies play an important role in limiting climate change and must either prepare for such consequences or adopt new strategies such as the sufficiency strategy.
This article will discuss how the sufficiency strategy and the promotion of sufficient living in the context of the tourism industry can contribute to reducing CO2 emissions. Most common approaches toward sufficient living found in literature will be identified, analysed and discussed. Based on chosen keywords, the most common approaches were identified through a literature review of relevant journals from 1989 to 2014. Four main research fields that can promote sufficient living and reduce CO2 emissions were identified. Based on the prospects of the companies, it is apparent that sufficient strategies are not only able to support a market-orientated corporate management but also promote sufficient living and thus reduce CO2 emissions.