Tuning the crystallite size of monoclinic ZrO_(2) to reveal critical roles of surface defects on m–ZrO_(2) catalyst for direct synthesis of isobutene from syngas  

作　　者：Xuemei Wu Minghui Tan Bing Xu Shengying Zhao Qingxiang Ma Yingluo He Chunyang Zeng Guohui Yang Noritatsu Tsubaki Yisheng Tan 

机构地区：[1]State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,Ningxia University,Yinchuan 750021,China [4]Department of Applied Chemistry,School of Engineering,University of Toyama,Gofuku 3190,Toyama 930-8555,Japan [5]China Petroleum Chemical Industry Federation,Beijing 100723,China

出　　处：《Chinese Journal of Chemical Engineering》2021年第7期211-219,共9页中国化学工程学报（英文版）

基　　金：financially supported by the Natural Science Foundation of China(21978312,21908235 and 21802155);the Key Research Program of Frontier Sciences,CAS(QYZDB–SSW–JS C043);Foundation of State Key Laboratory of Highefficiency Utilization of Coal and Green Chemical Engineering(2019-KF-05 and 2018-K22);Supported by Shanxi Scholarship Council of China and Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province are also greatly appreciated。

摘　　要：The effects of crystallite size on the physicochemical properties and surface defects of pure monoclinic ZrO_(2) catalysts for isobutene synthesis were studied.We prepared a series of monoclinic ZrO_(2) catalysts with different crystallite size by changing calcination temperature and evaluated their catalytic performance for isobutene synthesis from syngas.ZrO_(2) with small crystalline size showed higher CO conversion and isobutene selectivity,while samples with large crystalline size preferred to form dimethyl ether(DME)instead of hydrocarbons,much less to isobutene.Oxygen defects(ODefects)analyzed by X-ray photoelectron spectroscopy(XPS)provided evidence that more ODefectsoccupied on the surface of ZrO_(2) catalysts with smaller crystalline size.Electron paramagnetic resonance(EPR)and ultraviolet–visible diffuse reflectance(UV–vis DRS)confirmed the presence of high concentration of surface defects and Zr3+on mZrO_(2)-5.9 sample,respectively.In situ diffuse reflectance infrared Fourier transform spectroscopy(in situ DRIFTS)analysis indicated that the adsorption strength of formed formate species on catalyst reduced as the crystalline size decreased.These results suggested that surface defects were responsible for CO activation and further influenced the adsorption strength of surface species,and thus the products distribution changed.This study provides an in-depth insight for active sites regulation of ZrO_(2) catalyst in CO hydrogenation reaction.

关 键 词：SYNGAS ISOBUTENE ZrO_(2)catalyst Crystallite size Surface defects 

分 类 号：TQ426[化学工程]