“…The existence of specific bonding sites on catalysts is essential to trap reactant molecules in the initial interaction. The adsorption of CO on the metal surface, 12,24,[45][46][47] nanoparticles, 2,10,48 clusters, 33,34,[49][50][51] and single atoms dispersed on support 52 has been extensively investigated, and a diversity of CO adsorption has been discovered depending on the nature of metal sites. Understanding the electronic communication (s-donation or p-back donation) between CO and the active site is pivotal to dictate the direction of subsequent transformation.…”