Light‐Driven BiVO 4 –C Fuel Cell with Simultaneous Production of H 2 O 2

Abstract Photoelectrochemical (PEC) systems have been researched for decades due to their great promise to convert sunlight to fuels. The majority of the research on PEC has been using light to split water to hydrogen and oxygen, and its performance is limited by the need of additional bias. Another research direction on PEC using light, is to decompose organic materials while producing electricity. In this work, the authors report a new type of unassisted PEC system that uses light, water and oxygen to simultaneously produce electricity and hydrogen peroxide (H 2 O 2 ) on both the photoanode and cathode, which is essentially a light‐driven fuel cell with H 2 O 2 as the main product at the two electrodes, meanwhile achieving a maximum power density of 0.194 mW cm ‐2 , an open circuit voltage of 0.61 V, and a short circuit current density of 1.09 mA cm ‐2 . The electricity output can be further used as a sign for cell function when accompanied by a detector such as a light‐emitting diode (LED) light or a multimeter. This is the first work that shows H 2 O 2 two‐side generation with a strict key factors study of the system, with a clear demonstration of electricity output ability using low‐cost earth abundant materials on both sides, which represents an exciting new direction for PEC systems.