New progress in the preparation of high loading atom dispersion catalyst by USTC

When the metal particles are reduced to a certain scale (nanometer size or even atom level dispersion), due to their high atom utilization efficiency and unique electronic characteristics, the supported metal catalysts often exhibit high catalytic activity and specific selectivity However, with the decrease of metal particle size, the surface free energy of metal will increase rapidly, which will easily lead to metal agglomeration Traditional solutions usually sacrifice metal loading to prepare atom level dispersion catalysts, which greatly limits the practical application of such catalysts Recently, Professor Liang Haiwei's research group of University of science and technology of China, in cooperation with Dr Lin Yue and Chu Shengqi, associate researcher of Institute of high energy physics, Chinese Academy of Sciences, used high specific surface area sulfur doped mesoporous carbon (meso_s-c ）As a support, based on the principle of strong bond cooperation between precious metals and sulfur (according to the theory of hard and soft acids and bases, precious metals and sulfur belong to soft acids and bases respectively, so strong covalent bond can be formed between them), a series of highly loaded atom level dispersed precious metal catalysts, including Pt, IR, Rh, Ru and PD, are prepared, in which the metal Pt can reach 10 wt% (as shown in the figure) 1A) The research results were published in science advanced (DOI: 10.1126 / sciadv.aax6322) under the title of "a sulfur-curing synthesis strategy toward high-loading atomically dispersed noble metal catalysts" The first author of this paper is Wang Lei, a doctoral student Figure 1 Preparation and characterization of highly loaded atom dispersed noble metal catalysts (A) Synthesis route; (b) haaf-stem map of 10pt / meso_s-c; (c) EXAFS map of Pt / meso_s-c, PtO2 and Pt; (d) haaf-stem map of 10ir / meso_s-c; (E) EXAFS map of IR / meso_s-c and IR; (f) electrocatalytic oxidation of formic acid; (g) quinoline hydrogenation performance (source: Science Advanced) in this work, researchers first synthesized meso_s-c carrier with high sulfur content and high specific surface area by using the method of transition metal catalytic carbonization of organic small molecules developed in the early stage, and prepared a series of atom level dispersed noble metal catalysts by using the carrier by traditional impregnation method The results of spherical aberration corrected transmission electron microscopy showed that no nanoparticles or clusters were found when Pt and IR loading was less than 10% (Fig 1b and 1D); the results of synchrotron radiation X-ray absorption spectra showed that metals mainly existed in the form of metal sulfur (1.8-2.0 Å) coordination, and no metal metal (2.5-2.8 Å) coordination (Fig 1c and 1E) was found Metal exists in the form of atom dispersion, and the bonding between metal and sulfur is verified In the electrocatalytic oxidation of formic acid, the mass activity of atom level dispersed Pt catalyst (10pt / meso_s-c) reached 2.38 a, more than 30 times of that of commercial Pt / C catalyst (Fig 1F); in the catalytic hydrogenation of quinoline, the TOF value of atom level dispersed IR catalyst (5ir / meso_s-c) reached 1292 H-1, more than 20 times of that of commercial IR / C catalyst (Fig 1g) This work provides a new idea for the universal preparation of high loading atom level dispersed noble metal catalysts The research was supported by the National Natural Science Foundation of China, the youth program of the thousand talents program, the special fund for basic scientific research business expenses of the Central University, the natural science foundation of Anhui Province, and the synchrotron radiation joint fund of the University of science and technology of China.