The graphic enables the visualization of the changes in audible frequency within the cell when the potential is applied at 30 s. The change in frequency is related to the gas volume produced during electrolysis. The gas changes the compressibility of the electrolyte slowing down the speed of sound.

The use of earth-abundant materials for novel electrodes for solar-driven electrolysis will play a significant role in the future production of hydrogen as a green energy source. The choice of electrolyte will play a major role in how efficient and stable future photoelectrochemical cells (PEC) operate. A new approach to determining PEC efficiency using broadband acoustic resonance dissolution spectroscopy (BARDS) is investigated to analyze the real-time production of hydrogen and oxygen at platinum electrodes in different electrolyte solutions. The parameters investigated include concentration of electrolyte, surface area of the electrode, and the potential applied to the cell. Herein, the suitability of neutral buffer as an electrolyte on a par with either acid or basic electrolytes is shown. This finding allows for the potential design of solar to hydrogen electrolysers which can operate under mild, neutral, and stable conditions using earth-abundant materials for hydrogen production. It is also shown how BARDS can readily visualize and track gas evolution in real-time and in situ in an open system without the need for gas collection. It is anticipated that the technique can be utilized in the future evaluation of newly developed electrode materials in terms of efficiency, stability, and life span.