Thermally Driven Electrolysis Triggered via p <i>K</i> a Shift of Temperature Responsive Hydrogel Particles

Abstract We report a thermally driven electrolysis system utilizing the temperature-dependent volume phase transition of hydrogel nanoparticles. The pKa shift of carboxylic acids in the nanoparticles induced by the phase transition generates a pH gradient in a aqueous solution along temperature gradient. When a temperature gradient was applied to the thermoelectrochemical cell with the hot and cold solutions connected via an electronic circuit with an appropriate supporting potential, hydrogen was generated at the low-temperature cathode. This electrolytic Hydrogen generation system enables energy conversion from low-grade heat (&amp;lt;70°C) to storable hydrogen.