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Only a few materials can remain undissolved under working conditions for the oxygen evolution reaction (OER) in acidic media, which limits the choice of catalysts and supports. One of the practical catalyst/support candidates is IrO x /Sb:SnO2 (Ir/ATO) because both components are thermodynamically stable under low-pH anodic conditions. Moreover, between Ir and ATO, a strong metal–support interaction is present, thereby allowing for long-lasting OER activity unless the support degrades. However, we demonstrate that the strong interaction can paradoxically deactivate Ir/ATO structures when synthesizing them using the polyol process. We reveal that the strong interaction in the presence of polyol at elevated temperatures can cause the reduction of the Sb dopant to zero-valency. Findings show that the varied oxidation state of the dopant decreases the electrical conductivity of the Ir/ATO, impeding the electron transfer through the support, hence deteriorating electrocatalytic activity toward the OER.

Iridium­(Ir)-based electrocatalyst exhibits an optimal trade-off between catalytic activity and stability and thus is considered one of the most promising candidates in acidic water oxidation electrocatalysis. Due to its cost and scarcity, however, the sparing use of it has become the top priority in this field. In this contribution, we demonstrate the immense potential of coaxial arc plasma deposition (APD) as catalyst coating technology for water oxidation. Taking advantage of controllable pulsed plasma generation with high kinetic energy, APD enables the rigid coating of uniform and ultrathin Ir films on the substrate surface. The strong anchoring propensity of the films is observed, and thereby, unless the Ir loading is too little to overcome the catalyst loss and dissolution caused during repetitive electrochemical redox cycling for full electrocatalyst activation, the electrocatalytic performance of the films remains unaffected even after thousands of cyclic water oxidation testing. In this regard, we scrutinize the threshold Ir loading required to elude the entire loss of catalyst and report the threshold value as a result of an analytic investigation into the correlation between the number of APD shots and the resulting mass of the iridium loading.

Hair follicles in the skin undergo cyclic rounds of regeneration, degeneration, and rest throughout life. Stem cells residing in hair follicles play a pivotal role in maintaining tissue homeostasis and hair growth cycles. Research on hair follicle aging and age-related hair loss has demonstrated that a decline in hair follicle stem cell (HFSC) activity with aging can decrease the regeneration capacity of hair follicles. This review summarizes our understanding of how age-associated HFSC intrinsic and extrinsic mechanisms can induce HFSC aging and hair loss. In addition, we discuss approaches developed to attenuate age-associated changes in HFSCs and their niches, thereby promoting hair regrowth.