H2-driven NADH regeneration has long suffered from low selectivity when non-enzymatic, particularly heterogeneous catalysts, are used. In addition to the unselective nature of the catalysts, the typically unmeasured NAD+ conversion has inevitably hindered catalyst development. Here we report Sn-doped Pt/SiO2 catalysts for the selective regeneration of NADH and show that doping Pt/SiO2 with 10 at.% Sn can deliver a selectivity of 90% (at ~100% conversion) using H2. We propose that this is a result of Sn disturbing the Pt ensemble, altering the mode of NAD+ adsorption and directing the reduction to the 1,4- position of the nicotinamide ring.