Restructured PtNi on ultrathin nickel hydroxide for enhanced performance in hydrogen evolution and methanol oxidation

Abstract

Due to the negative impact of overusing traditional fossil fuels on the environment, electrochemical reactions that can minimize the generation of toxic materials during the process, including hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR), have been drawing increasing attention. In order to get more outstanding catalysts for both HER and MOR, we combined well-defined PtNi concave nanocubes (CNCs) bounded by high-index facets (HIFs) with Ni(OH)2 nanosheets via a facile hydrothermal process and successfully obtained hybrid PtNi/Ni(OH)2−x, where x means the initial mass of Ni(OH)2 in the synthesis. Remarkably, after the combination, the smooth surfaces of as-prepared PtNi CNCs were transmuted into rough ones made up of PtNi nanospheres (5–7 nm), with Ni(OH)2 nanosheets serving as the substrate. Therefore, benefiting from the merging step, the open-framework structure with more active sites exposed was formed. Besides, the unique synergistic effect and electronic effect inside PtNi alloy and between PtNi to Ni(OH)2, as well as the appropriate mass ratio of the two components make PtNi/Ni(OH)2-4.0 an excellent electrocatalyst with enhanced activity and promoted stability for both HER and MOR, which is superior to that of commercial Pt black and PtNi CNCs enclosed by HIFs. We believe that this work may potentially be applied in effective electrocatalyst construction and energy conversion.