Rational design of trifunctional electrocatalysts with robust efficiency used for oxygen reduction, oxygen evolution, and hydrogen evolution reactions (ORR, OER, and HER) is of significance to renewable energy conversion techniques, which remains a challenging issue. This study integrates dominant Co/Co3O4 with a small fraction of RuO2 and the CoRu alloy anchored on a hollow carbon matrix, originating from the novel Ru-doped hollow metal–organic framework (MOF) precursor, which is synthesized via tannic etching and ion exchange. Notably, the introduced ultralow Ru (1.28 wt %) not only generates new Ru-based species but also induces a Ru-enriched surface with abundant oxygen vacancies. Moreover, a suitable balance among different valencies of Co or Ru can be tuned by oxidation time, resulting in preferable Co2+ and Ru4+ species. Triggered by these unparalleled surface properties along with good conductivity, hollow structure, and the synergistic effect of multiple active sites, the resulting CoRu-O/A@hollow nitrogen-doped carbon (HNC) shows robust catalytic performance for ORR/OER/HER in an alkaline electrolyte. Typically, it exhibits a potential gap of 0.662 V for OER/ORR and enables an alkaline water electrolyzer with a cell voltage of 1.558 V at 10 mA cm–2. This work would serve as guidance for well construction of transition-metal-based trifunctional electrocatalysts by the MOF-assisted strategy or the modulation effects of low-content Ru.

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The steady-state multiplicity in azeotropic distillation processes has been theoretically predicted and verified experimentally for decades. However, it is a tough task to detect all the steady-state solutions. The purpose of this article is 2-fold: first, it provides a systematical study on the multiplicity in homogeneous azeotropic distillation with intermediate entrainer and a novel strategy is proposed to find all the steady-state solutions using "Design Specs/Vary" in Aspen Plus. Operating on the unstable steady-state branch benefits both energy saving and reducing capital investment with the product quality specified. Because of the great benefits that operating on the unstable steady-state branch offers, the second purpose is to present suitable control schemes to stabilize the operating point on the unstable steady-state branch to achieve robust control.