Alcohol oxidation with 100 % selectivity to the aldehyde product (versus acid formation) is achieved at mild conditions by a tandem-type system where the intermediate species of hydrogen peroxide formation from an O 2 /H 2 mixture are formed and utilised directly over Au-Pd/Ti-NT catalysts. In situ reaction of the intermediate species minimises the parallel decomposition of hydrogen peroxide into water, overcoming one of the limitations on the use of hydrogen peroxide as a green oxidant.There is a current significant scientific effort concerning the development of cleaner catalytic selective oxidation processes using hydrogen peroxide,[1] molecular oxygen [2] and compressed air [3] to substitute stoichiometric oxidants at industrial scale. In particularly, hydrogen peroxide (H 2 O 2 ) is an oxidising agent with a high active oxygen content that produces only water as a co-product. However, the large scale use of H 2 O 2 still presents a series of challenges associated with waste production from its anthraquinone autoxidation synthesis and safe transport and storage. Consequently, there has been continuing interest in the local direct synthesis of hydrogen peroxide from H 2 and O 2 .[4] We have recently reported the high activity of Au-Pd nanoparticles supported on titanate nanotubes (Ti-NT) for the direct synthesis of H 2 O 2 with productivities in excess of 10 kmol H 2 O 2 kg metal À1 h À1. The high activity of these nanostructured catalysts is attributed to a very small metal particle size (< 1.5 nm) and high dispersion afforded by its high metal-support interaction and physical constraints created by the high aspect ratio morphology of the support.[5] Despite the potential of this catalytic system, the hydrogen utilisation is compromised by the parallel decomposition of H 2 O 2 to water and oxygen. To avoid this problem, integration of the in situ generation and utilisation of hydrogen peroxide is presented as an efficient way of reducing cost, avoiding intermediate purification or separation steps, and transportation and storage of H 2 O 2 .[6] Ultimate integration would be achieved by aligning the rate of H 2 O 2 production and consumption, ideally with the use of only a single catalyst for both reaction steps.The current development of gold-based catalysts for oxidation reactions [7] and reported outstanding selectivities [7b, 8] has prompted the use of Au-Pd on titanate nanotubes as a catalyst for the tandem generation of H 2 O 2 and in situ oxidation reactions. An interesting oxidation reaction is the selective oxidation of o-hydroxy benzylalcohol (salicylic alcohol) to o-hydroxy benzaldehyde (salicylic aldehyde), which is an intermediate compound for the synthesis of pesticides, polymers, perfumes, etc., [9] and can serve as a model reaction for selective oxidation in aqueous phase. Several patents have covered this reaction [10] based on processes using palladium and platinum catalysts and promoters (bismuth, lead, tellurium, etc.). The current main limitation is the formation of by-products that a...