Role of Ba in an Al2O3‐Supported Pd‐based Catalyst under Practical Three‐Way Catalysis Conditions
Role of Ba in an Al2O3‐Supported Pd‐based Catalyst under Practical Three‐Way Catalysis Conditions
复制标题
实际三效催化条件下 Ba 在 Al2O3 负载 Pd 基催化剂中的作用
DOI：
10.1002/cctc.202101462
复制
发表时间：
2022
期刊：
影响因子：
4.5
通讯作者：
Toyao Takashi
中科院分区：
文献类型：
--
作者：
Jing Yuan;Wang Gang;Mine Shinya;Maeno Zen;Hakim Siddiki S. M. A.;Kobayashi Masayuki;Nagaoka Shuhei;Shimizu Ken‐ichi;Toyao Takashi
钡（Ba）已被广泛且成功地添加到三元催化剂中，以有效控制汽油车排放。众所周知，Ba 的引入对三效催化 (TWC) 性能具有非常显着的影响，但 Ba 在实际 TWC 条件下的作用仍不清楚。在这项研究中，我们使用汽油车和原位/操作红外 (IR) 光谱研究了标准 TWC 工艺中钯基催化剂中 Ba 的作用。研究发现添加 Ba 可以减少车辆废气中所有考虑的排放物（氮氧化物、一氧化碳和非甲烷碳氢化合物）；它还抑制了负载金属的聚集，这是高性能催化剂的要求。此外，使用模型粉末催化剂进行的红外研究表明，中间表面硝酸盐物种的有效形成及其随后与还原剂气体（例如CO、H2和C3H6（作为碳氢化合物））的反应在减少排放方面发挥着关键作用。此过程类似于常用于控制柴油排放的氮氧化物储存和还原 (NSR) 机制。
Barium (Ba) has been widely and successfully added to three‐way catalysts to effectively control gasoline vehicle emissions. While the introduction of Ba is well‐known to have a very significant impact on three‐way catalysis (TWC) performance, the role of Ba under practical TWC conditions remains insufficiently understood. In this study, we investigated the role of Ba in a Pd‐based catalyst in a standard TWC process using a gasoline vehicle andin situ/operandoinfrared (IR) spectroscopy. The addition of Ba was found to reduce all of the emissions considered (NOx, CO, and non‐methane hydrocarbons) in the vehicle exhaust gas; it also suppressed supported‐metal aggregation, which is a requirement of a high‐performance catalyst. In addition, IR studies using model powder catalysts revealed that the efficient formation of intermediate surface nitrate species and their subsequent reactions with reductant gases, such as CO, H2, and C3H6(as a hydrocarbon), play key roles in reducing emissions. This process is akin to the NOxstorage and reduction (NSR) mechanism commonly used to control diesel emissions.