Identification of Active Sites on High-Performance Pt/Al2O3 Catalyst for Cryogenic CO Oxidation
Identification of Active Sites on High-Performance Pt/Al2O3 Catalyst for Cryogenic CO Oxidation
复制标题
低温 CO 氧化高性能 Pt/Al2O3 催化剂活性位点的鉴定
DOI：
10.1021/acscatal.0c02253
复制
发表时间：
2020-08-07
期刊：
影响因子：
12.9
通讯作者：
Zhang, Tao
中科院分区：
文献类型：
--
作者：
Chen, Yang;Feng, Yingxin;Zhang, Tao
由于受到竞争的Langmuir-Hinshelwood过程的限制，在惰性衬底上负载的Pt物种在低温CO氧化中没有达到令人满意的性能，在这个过程中，强吸附的CO抑制了O-2的活化。她;我们在Al2O3上开发了一种Pt纳米颗粒催化剂，该催化剂在-20℃下具有100%的CO转化率，比目前的商用催化剂高出几个数量级。详细的催化剂表征揭示了Pt/Al2O3中存在金属Pt位点和与OH类相关的正电荷位点。实验数据和理论计算均表明，吸附在Pt（OH）结位上的CO与覆盖在Pt-0阶地位上的OH发生反应释放CO2。之后，O-2在梯田上很容易被激活以再生OH。OH基团的存在和Pt基团上的Pt结位和阶地位之间的协同作用导致了CO氧化的超低反应屏障。
Exclusive Pt species supported on inert substrates have not achieved satisfactory performance for cryogenic CO oxidation because of the constraint of the competitive Langmuir-Hinshelwood process in which the strongly adsorbed CO inhibits the activation of O-2. Her; we develop a catalyst of Pt nanoparticles on Al2O3 that exhibits extremely high activity with 100% CO conversion at -20 degrees C and orders of magnitude higher specific rate than current commercial catalysts. Detailed catalyst characterizations reveal the presence of metallic Pt sites and positively charged ones associated with the OH species in Pt/Al2O3. Both experimental data and theoretical calculations suggest that CO adsorbed on Pt(OH) kink sites reacts with OH species covering Pt-0 terrace sites to release CO2. Afterward, O-2 is facilely activated on terrace sites to regenerate OH. The presence of OH species and the synergy between Pt kink and terrace sites on the Pt species lead to an ultralow reaction barrier for CO oxidation.