Atomic-Scale Pd on 2D Titania Sheets for Selective Oxidation of Methane to Methanol

Owing to maximally exposed active sites and a unique electronic structure, atomically thin two-dimensional semiconductor catalysts and atomic-scale metal co-catalysts are beyond their conventional bulk limit, especially for catalysis. Here, we report a two-dimensional titania (2DT) sheet-supported atomic-scale palladium (Pd1/2DT) via a stepwise solvothermal reaction and photochemical reduction approach. Such synthesized 2DT sheets have a layer structure, with a measured optical onset at ∼2.86 eV. An atomically thick 2D structure not only exhibits short-distance migration of photo-induced charge carriers but also provides more anchoring sites to stabilize atomic-scale Pd1 species, thus promoting the separation of charge carriers and stability of Pd1. This Pd1/2DT can catalyze methane conversion to methanol with a selectivity of 94% by using low-energy photons (λ > 420 nm) of solar light. Our work demonstrates that atomically low-dimensional catalysts can result in new and useful catalytic behaviors.