Formic acid (FA), which is obtainable through CO2 hydrogenation with green hydrogen or biomass conversion, has been used as a prospective liquid organic hydrogen carrier (LOHC) because of the abundant advantages of renewability, wide availability, stability, and high volumetric capacity (53 g H2/L). The development of highly efficient catalytic systems to achieve enhanced catalytic activity is attractive but still challenging. Herein, ultrafine and highly dispersed PdAu nanoclusters (NCs) anchored on amino-modified reduced graphene oxide (ArGO) were successfully synthesized via a facile impregnation-reduction method and applied as a catalyst toward formic acid dehydrogenation (FAD). Benefiting from the promoting effect of amino groups, the strain and ligand effect in the alloy, and the Mott–Schottky effect between PdAu NCs and ArGO, the resultant PdAu/ArGO affords an ultrahigh activity under visible light irradiation with an exceptional turnover frequency value of 10,699.5 h−1 at 298 K without any additives, more than 2.6 times improvement than that under dark, which is the highest among all reported catalysts under the same conditions. This study provides a green and convenient strategy for developing more efficient and sustainable FAD catalysts and promotes the effective utilization of FA as a prospective renewable LOHC.