Catalytic synthesis of glucaric acid by oxidation of gluconic acid/glucose using novel TiO2-supported bimetallic PtCu catalysts and O-2 as oxidant is reported, with significantly enhanced activity and selectivity compared to those in previous work. Bimetallic alloy Pt1Cu3 catalysts supported on TiO2 display unusual synergy and exceptional oxidation activity (3543 h(-1)) compared with monometallic Pt and Cu catalysts (13-550 h(-1)), with 46% glucaric acid selectivity at 45 degrees C and 0.1 MPa O-2. Further, it is shown with the PtlCu3 alloy catalyst that glucose may also be directly oxidized to glucaric acid and co-products (tartronic and oxalic acids). The oxidation catalyst reported here provides a green route for making glucaric acid, eliminating conventionally used stoichiometric reagents such as mineral acids and bleach enhancers. (C) 2015 Elsevier Inc. All rights reserved.