Chemical fuel generation by solar driven water splitting to hydrogen and CO₂ reduction to hydrocarbons is attractive to supply the sustainable energy. The design and fabrication of photoelectrode materials that are able to harvest sunlight and then produce excitons for chemical reactions is an important scientific challenge. In this presentation we will talk about our efforts to engineer both photoanode and photo/cathode materials from the perspectives of light absorption improvement by forming heterojunctions, electronic band structure manipulation by controlling the surface states and energetic level alignment, as well as surface catalysts optimization with the aim to improve their capability in sunlight harvesting range and charge carrier transport efficiency. The resultant nanostructures could be employed in a photoelectrochemical tandem cell for unbiased solar fuel generation.