Sailing into uncharted waters: Recent advances in the in situ monitoring of catalytic processes in aqueous environments

Catalysis in aqueous environments attracts enormous interest. Many characterization methods are well established at gas-solid interfaces, yet the majority of surface science approaches are limited to model surfaces and vacuum conditions. However, practical scenarios with complex catalyst structures, elevated temperatures and pressures, as well as the presence of two or more condensed phases, can pose immense challenges to these techniques, particularly for catalysts at their dynamic working states. In such contexts, this review highlights the advancement over the past five years in the in situ and time-resolved detection of catalytic processes and related phenomena in aqueous media, ideally under realistic conditions. We highlight latest technical innovations and novel chemistries that are made possible by recently developed toolboxes. Future directions of in situ and time-resolved analytical approaches applicable to aqueous phase catalysis are also presented.