The scalable and sustainable production of hydrogen fuel through water splitting demands efficient and robust Earth-abundant catalysts for the hydrogen evolution reaction (HER). Building on promising metal compounds with high HER catalytic activity, such as pyrite structure cobalt disulphide (CoS2), and substituting non-metal elements to tune the hydrogen adsorption free energy could lead to further improvements in catalytic activity. Here we present a combined theoretical and experimental study to establish ternary pyrite-type cobalt phosphosulphide (CoPS) as a high-performance Earth-abundant catalyst for electrochemical and photoelectrochemical hydrogen production. Nanostructured CoPS electrodes achieved a geometrical catalytic current density of 10 mA cm(-2) at overpotentials as low as 48 mV, with outstanding long-term operational stability. Integrated photocathodes of CoPS on n(+)-p-p(+) silicon micropyramids achieved photocurrents up to 35 mA cm(-2) at 0 V versus the reversible hydrogen electrode (RHE), onset photovoltages as high as 450 mV versus RHE, and the most efficient solar-driven hydrogen generation from Earth-abundant systems.
The anticipatory guidance for the parents of twins involves information on feeding, the parent-twin relationship, and promoting a sense of self. Parents optimally attach to one infant only, a concept known as monotropy. Ambivalence, anxiety, and unequal attachments may result from the stressful nature of raising twins. The early diagnosis of twins, visualization via ultrasound, and postpartum identification of the distinctive aspects of each infant help establish separate bonds. This individualization promotes a sense of self, self-esteem, and enhances individuation, the process by which the personality is differentiated, developed, and expressed. The twin situation is triadic; the infants develop attachments to the primary care giver and their co-twin. Problems with this complex association include delayed onset of speech, decreased speech production, and cryptophasia (secret language) between twins. Strategies to prevent speech delay include as much one-on-one time as possible and consistent intervention and correction of speech errors. Anticipatory guidance seeks to identify potential sources of stress with the goal of seeking out advice, accepting any assistance offered, and attending to twins at the desired level of individualization.
The nanoscale quantification of the electrochemical behavior in metals is critical to understanding the microstructure-corrosion relationship and subsequently controlling it. Here, the application of advanced surface characterization techniques, atomic force microscopy, vertical scanning interferometry, digital holography microscopy, and other quantitative phase microscopy (QPM) techniques, for surface corrosion monitoring in metals at the nanoscale are systematically reviewed and discussed in detail. Interestingly, in situ, real-time nanoscale topography evolution that enables measurement of time-dependent local dissolution rate as often tracked from numerical construction of QPM is also presented. This study demonstrates the considerable attributes of correlative advanced techniques for identifying nanoscale corrosion mechanisms, enabling the informed development of next-generation inhibition technologies, and improving corrosion predictive models.
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