Low- and High-Index Faceted Pd Nanocrystals Embedded in Various Oxygen-Deficient WO _x Nanostructures for Electrocatalytic Oxidation of Alcohol (EOA) and Carbon Monoxide (CO)

This work suggests a modest hydrothermal method applied for the synthesis of oxygen-deficient WO _x ( x = 2.75, 2.83, and 2.94) nanomaterials with various morphologies, such as bundled nanorods (NR), nanobelts (NB), and nanosheets (NS), by changing the inorganic additives, such as HCl, NaHSO₄, and HNO₃. In addition, WO _x-supported high- and low-index faceted Pd nanoparticles (Pd-WO_2.75 NB, Pd-WO_2.83 NR, and Pd-WO_2.94 NS) have been successfully synthesized by a facile sonochemical method to enhance the high electrocatalytic activity of electrocatalysts for alcohol electrooxidation, including ethanol, ethylene glycol, and glycerol. Among the three different electrocatalysts, the versatile high-index {520} faceted Pd nanoparticles on WO_2.75 NB (Pd-WO_2.75 NB) show better electrocatalytic performance compared to low-index {100} faceted Pd-WO_2.83 NR and Pd-WO_2.94 NS nanocomposites. This work has identified that the high-density low-coordinated surface atom of Pd strongly interacts with alcohol, which facilitates C-C bond cleavage and may prevent the CO poisoning of nanoparticles. Furthermore, the high concentration of oxygen-deficient nano composites provided additional benefit for the generation of OH species and boosted the electrocatalytic performance of alcohols as well.