Cathodic-Potential-Induced Amorphous TiO_x Layer for Glycerol Valorization

Electrochemical oxidation offers a low-carbon pathway for glycerol valorization, yet it remains constrained by the inherent trade-off between activity and selectivity toward high value-added products. Here, we create H doped amorphous layer (H-a-TiO_x) on anatase TiO₂, thus enabling 992 mmol m^{- 2} h^{- 1} glycerol-to-glyceraldehyde conversion with >80% selectivity while demonstrating scalable and economically sustainable performance. X-ray absorption spectroscopy and solid-state ¹H magic angle spinning NMR spectra reveal that H-a-TiO_x exhibits reduced Ti-O coordination due to oxygen stripping, along with strengthened second shell Ti─Ti coordination arising from interstitial hydrogen incorporation. Mechanistic investigations indicate that hydrogen-bond strengthening around adsorbed hydroxyl (*OH) raises the energy barrier for C─C bond cleavage, whereas enhanced localization of *OH lowers that for C─H bond activation, thereby overcoming the activity-selectivity trade-off for glyceraldehyde production. This work outlines a practical phase-engineering strategy that enables sustainable electrosynthesis with earth-abundant metal oxides.