The Synthesis Of Sub-Nanometer Clusters And Study On Electrocatalytic Performance

Sub-nanometer clusters（SNCs）with integrated sites have attracted attention as active materials in many catalytic reactions.However,previous synthetic strategies have been unable to achieve higher loadings and have often used large amounts of solvent,greatly limiting their synthesis at scale.Therefore,the preparation of highly loaded and stable SNCs by a fast and green strategy is one of the main challenges faced by researchers.In this thesis,a series of high loading sub-nanoclusters have been synthesized via a microwave-assisted method and investigated the structure-activity relationship between their structural composition and the intrinsic activity of the acidic hydrogen evolution reaction（HER）.The main research contents are as follows:（1）In this chapter,we develop a new strategy to synthesize a series of high loading and stable noble metal SNCs（M/C-X,M for Pt,Pd,Ru.C for KB,CNT,r GO.X for O,N,S）in high yield（93.1%）and in only 40 s.In this chapter,the number and type of functional groups is optimized so that the number of functional groups is neither so excessive as to be agglomerated,nor too scanty to be underloaded,thus achieving high loading and stable of SNCs.When the O functional group was 8.9 at.%,the SNCs reached the maximum loading（47.1 wt.%or 5.3 at.%）.Meanwhile,the presence of the strong metal-support interaction（SMSI）allows the SNCs to be firmly anchored to the support,which greatly enhances their stability.The mass activity of Pt_0.6/KB-O_S5-40 with the highest loading is 27.3 A mg _Pt^-1 at 50 m V in acidic HER,which is much better than that of commercial Pt/C(4.3 A mg _Pt^-1).It is one of the catalysts with the highest mass activity so far.After 5 days of durability test,the catalytic performance of Pt_0.6/KB-O_S5-40 almost unchanged.（2）In this chapter,we achieve a scalable synthesis of WO_3-x with oxygen vacancies loaded on C(referred to as WO_3-x-C（O）)electrocatalyst for the first time via a microwave-assisted in situ partial topological transformation.By adjusting the reaction time to optimize the number of defects,the overpotential of the WO_1.92-C（O）is only 22m V at a current density of 10 m A cm^-2,which is significantly better than commercial Pt/C（32 m V）.The mass normalized ECSA for WO_1.92-C（O）is up to 95 m² g^-1,and the TOF reaches 1.41 s^-1 at 0.05 V vs.RHE,which reaches a level close to that of Pt.In situ characterisation and theoretical calculations indicate that WO_1.92-C（O）promotes the reactant enrichment and increases the intensity of adsorption for the reaction intermediates.This work unveils that this in situ solvent microwave-assisted topological conversion strategy can be used for scalable synthesis of stable SNCs for HER and other energy applications.