The shape-controlled synthesis of cuprous oxide (Cu$_2$O) photocatalysts with both low or high index crystal planes has received increasing attention due to their unique facet-dependent properties. Since they are cheap and earth abundant, these well-defined Cu$_2$O nanostructures are extensively used for different photocatalytic reactions, also because of their strong visible light absorption capability. However, further development will be still needed to enhance the efficiency and photostability of Cu$_2$O, which still limits its industrial application. We start this review by summarizing the synthetic advancement in the facet engineering of Cu$_2$O and other associated hybrid Cu$_2$O-based heterostructures with a special emphasis put on their growth mechanism. We then discuss different facet-dependent properties, which are relevant to photocatalysis. In the subsequent section, we present a critical discussion on the photocatalytic performance of faceted Cu$_2$O nanostructures during organic synthesis, hydrogen production, and carbon dioxide photoreduction. The relation between photocatalytic efficiency and product selectivity with exposed crystal facets or with different composition of hybrid nanostructures is also discussed. Finally, important strategies are proposed to overcome the photostability issue, while outlining the course of future development to further boost the technological readiness of well-defined Cu$_2$O-based photocatalysts.
Boosting hydrogen and methane formation on a high-entropy photocatalyst by integrating atomic d0/d10 electronic junctions and microscopic P/N heterojunctions
Using a dual plasma process to produce cobalt--polypyrrole catalysts for the oxygen reduction reaction in fuel cells -- part II: analysing the chemical structure of the films
Spin-polarized chiral ZnIn2S4 for targeted solar-driven CO2 reduction to acetic acid
Shanghai Jiao Tong University（上海交通大学）；Tongji University（同济大学）；East China University of Science and Technology（华东理工大学）；East China Normal University（华东师范大学）；Hefei Institutes of Physical Science, Chinese Academy of Sciences（中国科学院合肥物质科学研究院）；University of Science and Technology of China（中国科学技术大学）
