3,3',5,5'-Tetramethylbenzidine (TMB) is a new type of safe chromogen reagent, which is widely used in clinical testing, forensic examination, criminal investigation and environmental monitoring. Recently, Jinjie Wang from Shanghai University of Engineering and Technology used 3,3',5,5'-tetramethylbenzidine (TMB) as an indicator for tcharacterizing catalytic performance of CeO2.

Cerium dioxide (CeO2) is a widely used inorganic material. It is the most abundant element among rare earth elements. It has the advantages of stable chemical properties, excellent oxygen storage and discharge capacity and charge exchange capacity, and is non-toxic. It has become a kind of The widely used catalysts or catalyst carrier materials are used in the fields of three-way catalysts, fuel cells, photocatalysis and wastewater treatment.

It takes a long time or special equipment to evaluate the catalytic ability of cerium dioxide. So the researchers used the principle of 3,3',5,5'-tetramethylbenzidine (TMB) color development to develop a method to quickly evaluate the catalytic activity of CeO2.

Cerium dioxide materials have enzyme-like catalytic activity and are good artificial enzyme materials; TMB is a commonly used color developer in enzyme-like catalytic reactions, and can be oxidized by highly active hydroxyl substances in solution to produce colored substances. Researhers demonstrated for the first time that cerium dioxide can oxidize 3,3 ', 5,5'-tetramethylbenzidine (TMB) in an acidic solution without the presence of hydrogen peroxide, so that the solution changes from colorless to yellow. Therefore, they propose a new idea: based on the principle that the concentration of active hydroxyl species in the solution is related to the activity of oxygen in the cerium dioxide catalytic solution, the catalytic performance of cerium dioxide can be detected based on the degree of color change of TMB.

The researchers tested five different forms of CeO2, namely nanoflakes (NF), nanorods (NR), nanoparticles (NP), nanocubes (NC) and nanooctahedrons (NO), As a result, its catalytic activity can be quickly predicted within 10 minutes.

This study proves that the TMB method can quickly and accurately characterize the catalytic activity of CeO2 with different morphologies , and provides a simple and low-cost method for characterizing the catalytic performance of CeO2, which can be used for the pretreatment of synthetic materials filter.

References:

Jingxia Yang, Shuaishuai Peng,et al, Fast Visual Evaluation of the Catalytic Activity of CeO2: Simple Colorimetric Assay Using3,3',5,5'-tetramethylbenzidine as Indicator, Journal of Catalysis (2020), DOI: 10.1016/j.jcat .2020.05.016