A one-pot "shielding-to-etching" strategy to synthesize amorphous MoS2 modified CoS/Co0.85Se heterostructured nanotube arrays for boosted energy-saving H2 generation.

In this study, a facile one-pot "shielding-to-etching" strategy has been designed for the synthesis of amorphous MoS2 modified CoS/Co0.85Se heterostructured nanotube arrays (a-MoS2/CoS/Co0.85Se HNTs) as a highly efficient electrocatalyst for boosted energy-saving H2 production, using Co(OH)x(CO3)y nanorods as the template. Interestingly, these multi-composition and hollow structured products were achieved in a controllable manner via only a one-pot synthesis, in which the nanorods with shielding layers were firstly obtained and then converted into nanotubes through further etching reaction. Benefiting from the combined nature of multiple-component hollow nanostructures, the electronic structure of the electrocatalyst is efficiently modulated, the electron transfer and ion diffusion pathways are effectively shortened and abundant active sites are created, which leads to excellent activity for urea oxidation and hydrogen evolution reactions with the as-prepared a-MoS2/CoS/Co0.85Se HNTs being employed as the electrodes. As a result, the whole urea electrolysis cell exhibits a driven voltage of only 1.42 V to achieve a current density of 10 mA cm-2, surpassing most reported transition-metal-based electrocatalysts. Moreover, a battery-assisted urea electrolyzer was assembled as well to demonstrate the feasibility of practical less-energy-intensive H2 generation. The method developed in this work is expected to broaden the way of designing and synthesizing multiple-component hollow nanostructures for various applications.