The paper in npj | Material Sustainability explores the advancements and challenges of photoelectrochemical (PEC) systems for sustainable energy and chemical production. PEC technology harnesses solar energy to drive clean fuel production, serving as a sustainable substitute for fossil fuels. By converting solar energy into chemical fuels through electrochemical reactions at semiconductor photoelectrodes, PEC has the potential to reduce greenhouse gas emissions and aid in achieving carbon neutrality objectives. Researchers are focusing on material developments such as titanium dioxide, zinc oxide, tungsten oxide, and bismuth vanadate as potential photoelectrodes to enhance efficiency. While TiO2 and ZnO are effective under UV light, BiVO4 shows promise in visible light utilization for solar water splitting. Strategies like doping techniques and nanostructuring are being explored to improve charge carrier density and light absorption. PEC systems face challenges in nitrogen fixation and CO2 reduction, with solutions including the use of engineered photoelectrodes and gas diffusion electrodes. Despite lower efficiencies compared to photovoltaic-electrolysis systems, PEC devices exhibit stability, operating continuously for over 1000 hours. Challenges like electrode degradation and system integration still hinder large-scale deployment. The research highlights the potential of PEC systems in sustainable chemical production by offering clean fuel options like hydrogen, chlorine, ammonia, and hydrogen peroxide. These systems have implications for decarbonizing transportation, industrial operations, and fertilizer production. PEC-driven CO2 conversion supports carbon recycling and storage, contributing to greenhouse gas mitigation and producing transportable fuels. While PEC technologies show transformative potential, addressing efficiency limitations and enhancing selectivity remain key areas for future advancements.