Scanning electrochemical microscopy at variable temperatures.

All chemical reactions are influenced by temperature, however, temperature is usually not considered an important parameter which has to be varied or at least controlled in SECM measurements. A precise temperature-control unit was designed and integrated into a SECM setup which allows setting the temperature of the sample and the adjacent electrolyte in a range between 0 and 100 °C without causing convection. Data acquisition was synchronized with the current pulses through the Peltier element to decrease the noise and keep the tip-to-sample distance constant during imaging. SECM images in the feedback mode, generator collector mode and the redox competition mode for model samples such as an enzyme entrapped within a polymer spot or oxygen reduction catalysts demonstrate the importance of controlling temperature as well as performing SECM experiments at predefined and constant increased temperature.