Vapor-Phase Atomic Layer Deposition of Nickel Sulfide and Its Application for Efficient Oxygen-Evolution Electrocatalysis

Vapor-phase atomic layer deposition (ALD) of nickel sulfide (NiS_<i>x</i>) is comprehensively reported for the first time. The deposition process employs bis­(<i>N</i>,<i>N</i>′-di-<i>tert</i>-butylacetamidinato)­nickel­(II) and H₂S as the reactants and is able to produce fairly smooth, pure, godlevskite-structured NiS_<i>x</i> thin films following an ideal layer-by-layer ALD growth fashion for a relatively wide process temperature range from 90–200 °C. Excellent conformal coating is demonstrated for this ALD process, as the deposited NiS_<i>x</i> films are able to uniformly and conformally cover deep narrow trenches with aspect ratio as high as 10:1, which highlights the general and broad applicability of this ALD process for fabricating complex 3D-structured nanodevices. Further, we demonstrate the applications of this ALD NiS_<i>x</i> for oxygen-evolution reaction (OER) electrocatalysis. The ALD NiS_<i>x</i> is found to convert to nickel (oxy)­hydrate after electrochemical aging, and the aged product shows a remarkable electrocatalytic activity and long-term stability, which is among the best electrocatalytic performance reported for nonprecious OER catalysts. Considering that ALD can be easily scaled up and integrated with 3D nanostructures, we believe that this ALD NiS_<i>x</i> process will be highly promising for a variety of applications in future energy devices

Age, composition, and tectonic significance of Palaeozoic granites in the Altyn orogenic belt, China

<div><p>ABSTRACT</p><p>We examined the petrography, litho-geochemistry, and geochronology of granite plutons in the Altyn orogenic belt, northern margin of the Qinghai–Tibet Plateau, to investigate the geodynamic history of the belt. The granites are peraluminous, with variable chondrite-normalized rare earth element patterns but generally similar trace element compositions; all are depleted in Ba, Nb, Sr, P, and Ti, and enriched in Rb, Th, Ta, Zr, and Hf. Their U–Pb zircon ages record multiple magmatic episodes between 500 and 404 Ma (north Altyn block (NAB)), 522 and 432 Ma (central Altyn block (CAB)), and 483 and 226 Ma (south Altyn block (SAB)). We propose a geodynamic model for the Altyn orogenic belt. Prior to 467 Ma, the north Altyn Ocean subducted southward below the NAB. The north Altyn region saw a change from subduction to collision between the Dunhuang block and the NAB during 467–450 Ma. The collision lasted until 430 Ma and was followed by post-collisional extension until 400 Ma. Farther south, the central Altyn Ocean subducted northwards beneath the CAB, resulting in 520–500 Ma granitic magmatism and leading to collision of the south Altyn micro-block (SAMB) with the CAB. Deep subduction of SAMB crust below the CAB resulted in granite intrusions during 490–455 Ma. The SAMB–CAB collision gave way to post-collisional extension, slab break-off, and delamination during 450–430 Ma. Bidirectional subduction of the south Altyn Ocean after ~485 Ma, dominated by southward subduction, continued until 456 Ma. Closure of the south Altyn Ocean led to continent–continent collision between the SAMB and the Qaidam block at 450–430 Ma, followed after ~410 Ma by repeated break-offs of slab segments until 337 Ma. Subsequent intrusions formed at 264–226 Ma in a setting of either post-collisional extension or sinistral strike-slip.</p></div