Surface Modifications of a Vertically Grown Nanostructure for Boosting Photoelectrochemical Water-Splitting Performance

Photoelectrochemical (PEC) water splitting is a promising approach for sustainable hydrogen production, driven by sunlight. To enhance the efficiency of PEC water-splitting systems, the development of efficient nanomaterials and architectures is crucial. Vertically grown nanostructures have emerged as a promising strategy to address several limitations of conventionally used PEC materials. Vertically grown architectures of nanomaterials offer various advantages such as increased light absorption by multiple reflections and scattering inside the material, decoupling in the direction of charge transfer and light absorption, maximizing the surface-area-to-volume ratio, which increases the electrode–electrolyte interface. Further heterostructure formation of these architectures can help to regulate the optoelectronic properties, which may help in enhancing the PEC performance. Heterostructure formation may involve different materials that absorb light at different wavelengths with favorable band positions. The process of heterostructure formation involves cocatalyst decoration, sensitization with different materials like quantum dots, plasmonic nanoparticles, etc. By carefully engineering the heterostructure composition and morphology, significant improvements can be achieved in the PEC performance, such as enhanced photocurrent density, extended photostability, and reduced onset potentials. The development of several advanced chemical and physical techniques, such as chemical vapor deposition, electrodeposition, hydrothermal, microwave, atomic layer deposition, etc., has enabled precise control over the heterostructure dimensions and composition, leading to desirable optoelectronic properties and optimized performance. In this Spotlight on Applications, we highlight advancements of vertically grown heterostructures for PEC water splitting. The integration of vertically aligned nanomaterials with optimized interfaces offers a promising pathway for the development of efficient and stable PEC water-splitting devices, paving the way toward sustainable hydrogen production from solar energy.