Dynamics of Heterogeneous Catalytic Processes at Operando Conditions

Abstract

The rational design of high-performance catalysts is hindered by the lack of knowledge of the structures of active sites and the reaction pathways under reaction conditions, which can be ideally addressed by an in situ / operando characterization. Besides the experimental insights, a theoretical investigation that simulates reaction conditions—so-called operando modeling—is necessary for a plausible understanding of a working catalyst system at the atomic scale. However, there is still a huge gap between the current widely used computational model and the concept of operando modeling, which should be achieved through multiscale computational modeling. This Perspective describes various modeling approaches and machine learning techniques that step toward operando modeling, followed by selected experimental examples that present an operando understanding in the thermo- and electrocatalytic processes. At last, the remaining challenges in this area are outlined.

Uncovering the Structure of Heterogeneous Catalysts Using Atomic Pair Distribution Function Analysis

“…And how does the structure change under reaction conditions? To answer these two questions for a particular system, the development of tailored in situ/operando setups to interrogate the structure of a catalyst under relevant reactive conditions is key [75][76][77][78]. Moreover, the design and construction of setups to allow the (quasi) simultaneous acquisition of X-ray total scattering data in combination with complementary spectroscopic techniques under reaction conditions, such as XAS, infrared, Raman or energy dispersive X-ray spectroscopies, would be highly valuable [70,[79][80][81].…”

Synthesis of Heterogeneous Catalysts in Catalyst Informatics to Bridge Experiment and High-Throughput Calculation

“…Searching heterogeneous catalysts is a challenging matter due to the high complexity of catalysis . In particular, catalysis involves complex interactions of the catalyst’s surface and gas molecules where the high complexities of gas adsorption, dissociation, and recombination are considered to simultaneously occur at the active sites. − In addition to this, process conditions such as temperature and gas flows impact the performance of the catalysts, resulting in difficulties in capturing how reactions are carried out under various process conditions and catalysts. − Thus, it is challenging to design and synthesize catalysts from unexplored high levels of complex catalyst space without understanding any underlying rules that may govern catalyst behavior.…”

Manganese Oxide as a Promoter for Copper Catalysts in CO2 and CO Hydrogenation

“…Another reason why the promotion of Cu nanoparticles by reducible oxides is far from fully understood is the dynamic nature of the catalysts under working (high‐pressure) conditions [38] and hence the need for operando studies. In situ X‐ray absorption spectroscopy (XAS) is a powerful technique with the ability to elucidate the nature of metal−Oxide species under reaction conditions [39–44] .…”