# Living Photoanodes for Solar-Driven Water Oxidation

## TL;DR

This review explores living photoanodes, which use photosynthetic microorganisms to convert solar energy into electricity or chemicals in sustainable technologies.

## Contribution

The paper provides a comprehensive review of recent advancements and strategies in developing living photoanodes for solar-driven water oxidation.

## Key findings

- Cyanobacteria are central to the photocatalytic and electron transport processes in living photoanodes.
- Theoretical models help estimate the maximum photocurrent outputs of these systems.
- Genetic engineering and electrode design are key strategies to enhance performance.

## Abstract

Photosynthetic microorganisms are abundant, self-sustaining
catalysts
that convert solar energy into high energy electrons. By interfacing
these living catalysts with electrodes, these electrons can be harnessed
for electricity generation or chemical production in sustainable solar-powered
technologies. The development of these so-called living photoanodes
is an emerging and highly interdisciplinary field that has progressed
substantially in recent years. In this review, we chart these advancements,
beginning with our current understanding of the fundamental biology
underpinning the key photocatalytic and electron transport processes
of oxygenic photosynthetic microorganismsnamely cyanobacteria.
We then describe theoretical approaches to estimating the maximum
obtainable photocurrent outputs of living photoanodes to gauge their
technological potential. Next, we discuss the main strategies employed
to attain these values which include genetic engineering, electrode
and diffusional/polymeric mediator design. Finally, in the outlook
section, we recommend standardized reporting methods to formalize
the field and propose future research directions to realize the full
potential of this nascent technology.