A Highly Versatile and Adaptable Artificial Leaf with Floatability and Planar Compact Design Applicable in Various Natural Environments.

As a promising means of solar energy conversion, photovoltaic (PV) cell-based electrolysis has recently drawn considerable attention for its effective solar fuel generation; especially the generation of hydrogen by solar water splitting. Inspired by remarkable accomplishments in enhancing the solar-to-hydrogen conversion efficiency, various efforts have aimed at fostering convenient and practical uses of PV electrolysis to make this technology ubiquitous, manageable, and efficient. Here, the design and function of a monolithic photoelectrolysis system-a so-called artificial leaf-for use in various environments are highlighted. The uniquely designed artificial-leaf system facilitates an unbiased water-splitting reaction by combining superstrate PV cells in series with single-face electrodes in a compact 2D catalytic configuration. Floatability is a new feature of the water-splitting artificial leaf; this feature maximizes solar light utilization and allows for easy retrieval for recycling. Additionally, its planar design enables operation of the device in water-scarce conditions. These characteristics endow the artificial leaf with versatility and a high adaptability to natural environments, widening the applicability of the device.