Synthesis And Studies Of Ultrathin Two-dimensional Nanomaterials For Hydrogen Evolution Of Electrocatalytic Water Splitting

Hydrogen production via electrolyzed water is a promising clean energy conversion technology.Hitherto,Platinum(Pt)is the best catalyst for the hydrogen evolution reaction(HER)catalyst due to its small overpotentials.However,due to scarce reserves and high prices,its commercial applications have been greatly restricted.Therefore,strategy to prepare an economical,efficient,and stable electrocatalyst is the key to solving the above problems.Herein,we focus on nickel and cobalt-based transition metals,the ultrathin two-dimensional(2D)nanosheets and the 2D materials confining single-atom catalysts(2DM(?)SACs)were synthesized.Through the adjustment of the morphology and electronic structure of catalysts to optimize the performance of materials,and enhancing HER activity ultimately.In addition,we tried to reveal the structure-activity relationship between the material structure and catalytic performance,which is of great significance for the rational design of electrocatalysts with high hydrogen evolution performance.The details of this article are as follows:(1)A simple synthetic method for preparing the ultrathin two-dimensional(2D)nanosheets and its confining single-atom catalysts was reported.Ultrathin Ni(OH)2 2D sheets and Co3O4 2D sheets were successfully prepared by changing different metal precursor types,and which of morphology and electronic structure were characterized and analyzed in detail.During the performance test of HER,these two ultrathin 2D structure catalysts exhibit an outstanding electrochemical HER performance than bulk materials,owing to their maximum atom-utilization efficiency and highly exposed specific crystal planes,and even comparable to Pt/C.(2)To further improve HER performance and make full use of the structural advantages of 2D materials,we have synthesized two 2D materials confining single-atom catalysts: Ru-Ni(OH)2 SACs and Ru-Co3O4 SACs.At the same time,detailed characterization methods,such as STEM,XAFS,XPS,revealed that the strong electronic interaction between the confined single atoms and the 2D structure host.Impressively,two catalysts demonstrates excellent HER performance over that of commercial Pt/C,with very low overpotentials and Tafel slopes in acidic and alkaline conditions.These results unambiguously show that synergistically coupling ultrathin 2D materials with single atoms can thoroughly unlock its potential in tuning catalytic activity and catalyst utilization efficiency,which plays a key role in improving the performance of HER.