(Physical and Analytical Electrochemistry Division David C. Grahame Award) Vignettes of Charge Transfer Processes at Interfaces Inspired By D.C. Grahame and Previous ECS Grahame Awardees

I am very humbled to be recognized with the 2023 ECS David C. Grahame Award. My presentation will start with the acknowledgment that this award does not happen without all the efforts of students, post-doctoral fellows and colleagues over the past 30 years. Notably, the basis of all my graduate work was inspired by Grahame’s 1947 seminal work [1] on electric double layers at metal-solution interfaces. The study of “clean” pseudo-single crystalline silver electrodes enabled us to quantify and understand the electrochemical formation of stable monolayers of various anions and cations, e.g. [2,3]. In hindsight, also I recognize that these studies provided me with the fundamental underpinnings and motivations to study charge transfer processes in much more complicated semi-metal- and semiconductor-solution systems using a plethora of experimental methods during my academic career. As discussed long ago by Gerischer [4], the key distinction between metal-solution and semiconductor-solution interfaces is that the mechanisms of charge transfer processes can be divided into many groups, mainly with those with weak interactions and the reactants in the electrolyte and those with strong interactions. A more complicating factor with semiconductor-solution interfaces is that the charge-transfer process typically involves both reaction with the electrolyte and a change in the conductivity of the electrode, e.g. [5]. I will provide a series of vignettes (case studies) inspired by several previous ECS Grahame awardees of the distinctive features of different charge transfer processes and their relation to energy conversion, energy storage and chemical sensing applications. [1] Grahame, D. C. Chem. Rev. 1947, 41, 441. [2] Stevenson, K. J.; Gao, X.; Hatchett, D. W.; White, H. S. J. Electroanal. Chem. 1998, 447, 43. [3] White, H. S.; Peterson, J.; Cui, Q; Stevenson, K. J. J. Phys. Chem. B 1998, 102, 2930. [4] Gerischer, H. 1969, 18, 97. [5] Nikitina, V. A.; Vassiliev, S. Yu; Stevenson, K. J. Adv. Ener. Mater. 2020, 1903933.