The synergistic effect Pt₁-W dual sites as a highly active and durable catalyst for electrochemical methanol oxidation

Downsizing precious metal catalysts such as Pt to the atomic level is considered effective and efficient in the catalysis industry. However, Pt single-atom alone cannot catalyze the MOR (methanol oxidation reaction) due to the requirement of Pt ensemble sites to activate C-O bonds. Herein, we report for the first Pt single atom dispersed on dual doped TiO₂ (Pt₁/ Ti_0.8W_0.2N_xO_y) as an effective and durable catalyst towards MOR. It is found that synergy between Pt₁-WO_3-x dual-active-sites enables the adsorption and dehydrogenation of methanol. Density functional theory (DFT) calculations reveal that W-site adsorbs methanol molecule and the synergistic cooperation between Pt₁-W dual active sites in Pt₁/Ti_0.8W_0.2N_xO_y contributes to the high catalytic activity, stability, and selectivity. The Pt₁/ Ti_0.8W_0.2N_xO_y catalyst displays high MOR performance with a mass activity of 560 mA mg⁻¹_Pt at 0.82 V vs. RHE in an alkaline medium. This activity is 9.3 and 1.3 times higher than the corresponding Pt nanoparticle (2 wt% Pt/ Ti_0.8W_0.2N_xO_y) and 20% Pt/C catalysts, respectively. The lower Tafel slope (93 mV dec⁻¹) and higher diffusion coefficient (1.5×10⁻¹² cm²/s) indicate MOR is faster on Pt₁/Ti_0.82W_0.18N_xO_y than the other catalysts. Furthermore, Pt₁/ Ti_0.8W_0.2N_xO_y oxidizes methanol to formate with 90% selectivity, whereas 2 wt% Pt/Ti_0.82W_0.18N_xO_y to formaldehyde with 69% selectivity. Moreover, after 10 h, Pt₁/ Ti_0.8W_0.2N_xO_y mass activity decayed only by 7.2%. In contrast, 2 wt% Pt/ Ti_0.8W_0.2N_xO_y and 20% Pt/C exhibited 23% and 43% of activity losses respectively.