Surface processes of CO_(2)reduction on Pt(210),Pt(310),and Pt(510)electrodes were studied by cyclic voltammetry.Different surface structures of these platinum single crystal electrodes were obtained by various treatment conditions.The experimental results illustrated that the electrocatalytic activity of Pt single crystal electrodes towards CO_(2)reduction is decreased in an order of Pt(210)>Pt(310)>Pt(510),i.e.,with the decrease of(110)step density on well-defined surfaces.When the surfaces were reconstructed due to oxygen adsorption,the catalytic activity of all the three electrodes has been enhanced to a cer-tain extent.Although the activity order remains unchanged,the electrocatalytic activity has been en-hanced more significantly as the density of(110)step sites is more intensive on the Pt single crystal surface.It has revealed that the more open the surface structure is,the more active the Pt single crystal electrode will be,and the easier for the electrode to be transformed into a surface structure that exhib-its higher activity under external inductions.However,the relatively ordered surfaces of Pt single crystal electrode are comparatively stable under the same external inductions.The present study has gained knowledge on the interaction between CO_(2)and Pt single crystal electrode surfaces at a micro-scopic level,and thrown new insight into understanding the surface processes of electrocatalytic re-duction of CO_(2).
FAN ChunJieFAN YouJunZHEN ChunHuaZHENG QingWeiSUN ShiGang
It was reported for the first time that phosphorictungstenic acid （PWA） could promote the oxygen reduction reaction （ORR） and inhibit the methanol oxidation reaction at the cathodic Pt/C catalyst in the direct methanol fuel cell （DMFC）. When the weight ratio of PWA to Pt/C is 1, the composite catalyst increases the reduction current of oxygen by about 38% and decreases the oxidation current of methanol by about 76% compared with that of the Pt/C catalyst.
Yan Zhuo LUTian Hong LUChang Peng LIUYa Wen TANGWei XING
We report a combined study of electrochemical experiments and ab initio calculations on tuning the surface reactivity of Pd via a compressive lattice strain achieved by employing nanoparticles of Pd-Cu alloys with a Pd-rich surface. Surface oxygen-containing species were used as the probing molecule for revealing the surface reactivity. Both density functional theory （DFT） calculations and experiments showed linear relationships, with very close slopes, between the adsorption strength of OHads and the Pd lattice constant. Not only is this work a successful realization of controllable modulation in the surface reactivity, but it also provides valuable information for the rational design of Pd-based catalysts for fuel cell applications.
