Rik Mom studied chemistry at Leiden University, where he became interested in the chemical reactions that take place at the surface of catalysts. Following this interest, he did his PhD in the group of Prof. Joost Frenken and Dr. Irene Groot, at the Leiden Institute of Physics, where he studied the structure of MoS2 particles during the catalytic removal of sulfur from organic molecules. Such operando studies require highly specialized equipment (a high-pressure scanning tunneling microscope in this case), which is home-built. This combination of instrument design and catalysis studies is what defined Rik’s further career, which he continued at the Fritz Haber Institute/BESSY synchrotron in Berlin. Here, he investigated the electrochemical conversion of water to oxygen on metal oxide electrodes using operando X-ray photoelectron spectroscopy and X-ray absorption spectroscopy, again developing and using purpose-built instrumentation. In his current position at Leiden University, he continues this tradition, with the current research focus on fuel cell and electrolyzer electrocatalysis.