Carbon Support Effects and Mechanistic Details of the Electrocatalytic Activity of Polyoxometalates Investigated via Square Wave Voltacoulometry

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• 作者：J. GonzalezJ. A. Coca-Clemente ; A. Molina ; E. Laborda ; J. M. Gomez-Gil ; L. A. Rincon
• 刊名：ACS Catalysis
• 出版年：2017
• 出版时间：February 3, 2017
• 年：2017
• 卷：7
• 期：2
• 页码：1501-1511
• 全文大小：770K
• ISSN：2155-5435

文摘

The catalytic activity of surface-confined molecular species, as affected by the nature of the support, has been investigated by square wave voltacoulometry (SWVC). This technique has proven to be very powerful and advantageous for the study of electroactive and electrocatalytic monolayers. Here, the value of SWVC for the elucidation of the catalytic species and routes when the catalyst can undergo multiple electron transfers is assessed. The redox behavior in acidic water solution of the immobilized Keggin type polyoxomolybdate [PMo₁₂O₄₀]^3– and its catalytic performance toward the reduction of bromate have been studied experimentally. Three different supports are considered: boron-doped diamond (BDD), bare glassy carbon, and graphene oxide modified glassy carbon. For all of them, the SWVC response enables the accurate identification and analysis of the catalytic pathways and species. Mechanistic details are easily obtained on the basis of the additivity of the contributions associated with the electron transfer and with the catalytic process to the SWVC response. The results obtained reveal the significant influence of the support on the redox properties and on the catalytic activity of the polyoxomolybdate. Among the supports tested, glassy-carbon supports show the highest catalytic performance with apparent rate constants that are up to 1 order of magnitude faster than those on BDD.