Surfactant-free Cu_xPt_y nano-alloys with controllable atomic ratios and their enhanced electrocatalytic activity

The electrocatalytic mechanisms of electrocatalysts were constrained by the disparities between the genuine catalytic interface and construction interface. This work demonstrated the relationship between the Cu_xPt_y nano-alloy atomic ratios and their catalytic performance. Firstly, we developed a facile synthesis of surfactant-free Cu_xPt_y nano-alloys with tunable Cu atomic ratios (ranging from 35 to 72 at%) under ambient conditions. Considering no surfactant-free was applied, surface active sites were uncovered, which was beneficial to ensured consistency between the calculated interface and the actual interface. Based on the experiment and calculation, the relationship between the Pt loading rate and electrocatalytic activity of Cu_xPt_y nano-alloy toward hydrogen evolution reaction (HER) was systematically investigated. Under the acidic media, the over-potential by Cu₇₂Pt₂₈ was 7.17 mV, which was 11.5% by the pure Pt nano-particles (NPs). The lower over-potential could be derived from a favorable d-band center of Cu₇₂Pt₂₈, which accelerated the adsorption and desorption of H⁺. The correlation between the d-band center and the electrocatalytic activity of Cu_xPt_y nano-alloy was investigated. Benefiting from the surfactant-free surface, the Cu_xPt_y nano-alloy exhibited a favorable electrocatalytic activity toward methanol detection. With the increase in methanol concentration, the anodic peak for methanol oxidation was linearly increased. The linear relationship endowed the Cu_xPt_y nano-alloy with a favorable sensor performance. It is suggested that the Cu_xPt_y nano-alloy with a higher Pt atomic ratio showed a wider detection range and the Cu_xPt_y nano-alloy with a higher Cu atomic ratio showed an enhanced sensitivity. The superior sensor performances could also be utilized for ethanol detection. This work demonstrated the favorable performance of the surfactant-free Cu_xPt_y nano-alloy toward hydrogen generation and alcoholic solution (methanol and ethanol) detection. Considering the experiential results were agreed well with calculation, this work pave the way for designing cost-effective electrocatalysis by optimizing its d band center and maximized active sites.