Bridging the Time Gap: A Copper/Zinc Oxide/Aluminum Oxide Catalyst for Methanol Synthesis Studied under Industrially Relevant Conditions and Time Scales

Abstract

Long-term stability of catalysts is an important factor in the chemical industry. This factor is often underestimated in academic testing methods, which may lead to a time gap in the field of catalytic research. The deactivation behavior of an industrially relevant Cu/ZnO/Al2 O3 catalyst for the synthesis of methanol is reported over a period of 148 days time-on-stream (TOS). The process was investigated by a combination of quasi in situ and ex situ analysis techniques. The results show that ZnO is the most dynamic species in the catalyst, whereas only slight changes can be observed in the Cu nanoparticles. Thus, the deactivation of this catalyst is driven by the changes in the ZnO moieties. Our findings indicate that methanol synthesis is an interfacially mediated process between Cu and ZnO.

Methanol Synthesis from Industrial CO2 Sources: A Contribution to Chemical Energy Conversion

“…Figure 10 shows a TEM image of the sample after methanol synthesis in the presence of benzene. After reaction wurtzite ZnO nanoislands have formed on top of the Cu nanoparticles, which was also observed on the same catalyst in the initial stages of reaction [23]. Corrugation at the surfaces may indicate a remaining ZnO overlayer as it has been described for this type of catalyst after reductive activation [39].…”

“…Sahibzada et al [16] showed that a lower methanol production rate is observed with addition of water to the H 2 /CO 2 feed. Another possible reason of catalyst deactivation is crystallization of Cu and ZnO particles [23]. Water produced during methanol synthesis from CO 2 -rich feed can accelerate the crystallization of particles leading to deactivation that was observed for the Cu/ZnO/ZrO 2 / Al 2 O 3 catalyst [19].…”

IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer

“…Furthermore, our study shows that within a nanostructured Cu/metal oxide system, the Cu-moieties are not completely reducible, most probably at the interfacial contact of the metal and the metal oxide. The importance of the Cu/ZnO interface in reverse water-gas shift and methanol synthesis reactions was recently evidenced [42,43].…”

“…In the present study reduced catalysts have been studied. The surface may change under reaction conditions [42]. Therefore, DRIFTS investigations of used catalysts transferred to the measurement cell without air contact and DRIFTS studies under operation at 30 bar pressure are currently underway.…”

Local Information Powers Heterogeneous Catalysis Research:TEMInvestigation of Industrial Relevant Cu/ZnO/Al2O3 Catalysts for Methanol Synthesis

“…1b In addition, we will highlight the temperature, gas and time dependent evolution of this metastable layered ZnO polymorph from minutes to months (Figure 1). 3 In conclusion, the results demonstrate the power of local TEM investigation in heterogeneous catalysis research. In combination with complementary integral data, they allow a detailed understanding of the system, which would be otherwise hard to obtain.…”