Years of research have demon-strated that the use of multiple components is essential to the develop-ment of a commercial photoelectrode to address specific bottlenecks,such as low charge separation and injection efficiency,low carrier diffusion length and lifetime,and poor durability.A facile strategy for the synthesis of multilayered photoanodes from atomic-layer-deposited ultrathin films has enabled a new type of electrode architecture with a total multilayer thickness of 15-17 nm.We illustrate the advantages of this electrode architecture by using nanolayers to address different bottlenecks,thus producing a multilayer photoelectrode with improved interface kinetics and shorter electron transport path,as determined by interface analyses.The photocurrent density was twice that of the bare structure and reached a maximum of 33.3±2.1 mA cm-2 at 1.23VRHE.An integrated overall water-splitting cell consisting of an electrocatalytic NiS cathode and Bi2S3/NiS/NiFeO/TiO2 photoanode was used for precious-metal-free seawater splitting at a cell voltage of 1.23 V without degradation.The results and root analyses suggest that the distinctive advantages of the electrode architecture,which are superior to those of bulk bottom-up core-shell and hierarchical architectures,originate from the high density of active sites and nanometer-scale layer thickness,which enhance the suitability for interface-oriented energy conversion processes.