4 CONCLUSIONS AND PERSPECTIVES
This review underscores the critical role of interface engineering in optimizing the efficiency of PEC catalysts, providing valuable insights into recent research trends and contributing to the global pursuit of carbon neutrality. Interface engineering emerges as a pivotal strategy, optimizing cocatalysts, functional engineering, and defect engineering to overcome existing limitations. Noble metal cocatalysts, such as Ag and Au, are seamlessly integrated with plasmonic materials to induce surface plasmon resonance, thereby enhancing light absorption and catalytic efficiency for photocatalytic CO2 reduction. This enhancement is evident in various studies utilizing diverse plasmonic nanostructures and synthesis methods. When semiconductor materials are integrated with various cocatalysts, including noble metals, cobalt-based molecular catalysts, and non-noble metal materials, they demonstrate promising advancements in enhancing efficiency, selectivity, and stability for photocatalytic CO2reduction. Semiconductor heterojunctions, encompassing type-I, type-II, and Schottky barrier junctions, play a pivotal role in enhancing PEC CO2RR by facilitating the separation of photogenerated electrons and holes through distinct band structures. Nanostructure engineering further augments photocathode performance by manipulating materials on the nanometer scale, employing structures such as nanorods, nanowires, and core/shell configurations. Defect engineering, involving native point defects like vacancies and interstitials, influences catalytic, electrical, and optical properties. These defects, classified as 0D (point defects), 1D (line defects), 2D (interface defects), and 3D (bulk defects), enhance photoactivity in heterogeneous catalysis. Despite numerous research outcomes, interface engineering still requires further studies, and researchers posit that several topics will need more in-depth exploration.
· The PEC process based on interface engineering often involves complex procedures and expensive equipment, necessitating the development of more streamlined and cost-effective approaches.
· Extensive research is required to assess the long-term performance, stability, and durability of catalysts used in CO2reduction experiments, particularly in challenging environmental conditions.
· Current investigations into PEC CO2RR predominantly yield C1 products; therefore, a critical need exists for comprehensive studies focusing on C2+ products, which offer higher value-added potential.
· To facilitate the commercialization of catalysts, validating their performance on a larger scale within the existing laboratory setting is essential. This includes emphasizing creating and evaluating larger-area catalysts when implementing interface engineering technology.
Researchers have made significant strides in addressing these challenges. Notably, PEC co-catalysts have demonstrated potential in improving PEC system performance by effectively capturing and segregating photogenerated charge carriers while minimizing recombination. However, the implementation of these co-catalysts still encounters diverse challenges. Common issues associated with PEC systems exist, along with strategies aimed at overcoming them. The mere application of a co-catalyst onto the photoelectrode surface proves insufficient for constructing a robust and efficient PEC cell. Consequently, engineering the interface between co-catalysts and the photoelectrode surface becomes imperative for facilitating the desired reactions. Strategies to enhance PEC efficiency and stability involve the incorporation of suitable interlayers, transport layers, and electron-blocking layers. While co-catalysts play a pivotal role in promoting desired PEC reactions, their inefficient utilization can hinder overall performance. To address this concern, facile strategies such as optimizing co-catalyst loading and integrating them into composite materials need exploration. This approach aims to improve the surface area and active sites of the co-catalysts. Additionally, designing efficient configurations, such as core/shell structures with multijunction components, represents an effective means of enhancing co-catalyst utilization and overall efficiency. In summary, this review paper explores current trends in PEC CO2 reduction research from the perspective of interface engineering. By identifying these trends, the paper aims to make a significant contribution to the broader field of carbon dioxide reduction research.