The direct hydrogen peroxide (H2O2) synthesis from H2 and O2 is a strongly desired reaction for green processes and a promising alternative to the commercialized anthraquinone process. The design of efficient catalysts with high activity and H2O2 selectivity is highly desirable and yet challenging. Metal dopants enhance the performance of the active phase by increasing reaction rates, stability, and/or selectivity. Identifying efficient dopants mostly relies on catalysts prepared with the random and non-uniform deposition of active and promoter phases. To study the promotional effects of metal doping on palladium catalysts, we employ colloidal, bimetallic nanocrystals (NCs) to produce catalysts where the active and doping metals are co-localized to a fine extent. In the absence of any acid and halide promotors, PdSn and PdGa NCs (PdSn/s-TiO2, PdGa/s-TiO2) were highly efficient and clearly outperformed the monometallic palladium catalyst (Pd/s-TiO2), while in the presence of acid promotor the overall H2O2 productivity was also further enhanced for the Ni-, Ga-, In-, and Sn-doped catalysts with respect to Pd/s-TiO2.