In the first step of generating reaction networks for the eight template structures in Figure , we include MA and each of the catalyst templates in the meta-MD run. Before doing another step of the reaction discovery workflow, we add pNBA to the reaction mixture. Since we only consider elementary reactions between two molecules, in case more than two molecules are present in an intermediate, we only search for reactions between the two largest molecules. The eight reaction networks vary a lot in size after three iterations of the procedure. For formic acid (C8), the network consists of only 13 intermediates (Figure ) while for phosphine (C5) the network consists of 298 intermediates (Figure ). For some of the catalyst templates (C3, C5 and C6), the inclusion of tautomers adds a vast number of new intermediates; notice the number of yellow edges (proton transfer reactions) for phosphine (Figure ). Of the eight catalyst templates tested, only the reaction network for ammonia (C3) shows clear signs of catalytic activity, defined by the presence of a node with the catalyst regenerated and reaction free energy < 10 kcal/mol. For the remaining seven reaction networks, some show no intermediate/product with the template regenerated (C2, C6 and C7) while some have 1-3 intermediates with the catalyst regenerated but all with reaction Gibbs free energies >10 kcal/mol (C1, C4, C5 and C8). Phosphine (C5) is thus not recognized as a potential catalyst from the reaction network grown after three iterations. Below, we will analyze the behavior of phosphine in a bit more detail by comparing with the reaction network found for ammonia.